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Welcome to More Fun Making It

Hi, I’m Lee. I make awesome retro geeky things out of wood, electronics and patience.

I’ve also recently decided to regress to my teenage self. Much less squeezing spots and sleeping till the afternoon and much more obsessing over retro 8 and 16bit computers and consoles. My latest videos are much more about this new passion, but I’ll certainly be returning to woodwork soon!

You can find all of my builds here, the whole journey, including mistakes, awesome bits, mistakes, and the occasional stumble into success!

Playing on the finished products is so satisfying, but really, it’s more fun making it.

Restoring a lovely old ZX81 to its former glory

I quite like ZX81’s!
I have a few items in the repair pile and rather than being greedy and fixing them by myself I decided to turn on a couple of cameras and record them. Its been a little while since I fixed anything, and you can expect a few of these simple repair videos to be sprinkled in amongst the long form episodes I’m mostly making these days!
Paul sent me this ZX81 to repair. He gave it a test, plugged into RF and found it was, in his words “DEAD”.
I have my bench power supply set to 9v and 800mA and the TV tuned to the correct channel. Switching it on, it is indeed dead. Showing no signs of life on the screen. But watch what happens when I touch the power jack…
That looks like a black screen, but if we go closer you can see the expected K cursor is there, only the picture is very dark. That’s actually expected as the ZX81 outputs a very weak RF signal and this TV is modern enough that it really doesn’t like that.
Ok, so the first thing to address is that power jack. Let’s start taking some screws out and dig into this little machine.
The ZX81 was my very first computer and it still gives me warm feelings when I use one now. Even with its incredibly limited abilities it opened up a whole new world for me. I hope I never lose that feeling.
The membrane actually looks in reasonable condition for something over 40 years old. I have high hopes it won’t need replacing.
Inspecting the area underneath the power jack I can’t see any cracked solder joints, so it’s likely the socket is just very corroded. Let’s try some contact cleaner first. The power socket feels a bit loose. I wonder if someone tripped over a lead and stretched the insides of this at some point. Vigorous insertions should remove the worst of the crud. So does it work now? I can tell you it still does the same thing. And you can just see the picture flickering on the TV in the background as I wiggle the plug in the socket. There’s little point in trying to repair this socket. It’s a very cheap part and a new one will be much more reliable.
I’m using my manual solder sucker for this job. I could probably use the Hakko, but the nozzle won’t fit over these legs and the benefit would not be as great. Although I’m finding my Engineer sucker is blocking quite often lately. I might need to give it a thorough clean.
The pins are not yet moving, still a little too much solder, so in with the braid. Just to clean up the last bits.
And then moving the legs of the socket with the end of the soldering iron to free them. They’re all loose now and it just needs a little gentle persuasion.
Then it’s just a case of popping in the new socket and soldering it in place. Ah. It wont fit. Too much old solder left in the holes. Better clear that out first and then it will fit.
Still wont fit.
Ok. I better cheat then. File down the legs slightly and then it will fit!
Right, now with that fitted and all connected up again, will it work as expected?
Yes. Course it will.
And tapping on the power lead doesn’t have any effect. Perfect.
Next problem is the display. This machine will be sold by Paul Universal Retro Boss at some point and the new owner will most likely want to use it with a composite display. I have some really nice composite mod boards to replace the RF modulator. It’s not a simple composite mod like you will find in many ZX Spectrums. This one is a bit more involved and requires the modulator to be removed from the motherboard, replacing its guts with the new board.
It’s not too terrible to remove a modulator. The hardest part is getting all of the solder out of the holes in the heavy ground plane. But first I will remove the wires running from the modulator to the board. The nozzle won’t fit over these big legs so I am jamming it into the solder and sucking up as much as I can. Back to the braid to get the last bits. And now heating each leg and walking the modulator out of the board.
And it’s free.
It’s unlikely I’ll ever use the guts of this modulator again, it’s very old, and doesn’t work very well as we’ve seen earlier, and I have loads of them. But even so I prefer to try to remove the insides non destructively if possible. The old board has 3 or 4 large solder blobs around the outside. I first go at these with the Hakko gun and then work them loose with braid and wiggling.
And eventually it pops out. Now I need to make a replacement.
Here is my box of bits that Fuzzy Lee put together for me. There are enough parts to make dozens of composite boards for ZX80’s and 81’s.
Before starting the build I clean the board with IPA.
Diodes first. Starting with the lowest parts just makes things a bit easier.
Resistors next. Lee has marked all of the parts with the board locations so I don’t even need to refer to the github page. I’ll leave a link to the github in the description. I highly recommend these boards. I’ve tried a few different composite mods and not had much success till I found this one. Some ZX81 ULA’s produce a half decent video signal that includes the all important back porch. The good thing about this mod is that you don’t need to fit the 555 timer if your ULA does indeed produce a back porch. I don’t know if this particular ULA will need this or not. But we’ll find out together when I switch it on. If it needs that signal then fitting the 555 timer will allow this board to produce the full composite signal for a good quality image.
The last parts are the transistors and the legs on these are very close together. I don’t want to have to take this apart again so I check with a multimeter to make sure I haven’t bridged them.
And now it’s time to fit this into the can. You can see around the outside there are three large pads. I’ll be using these to solder the board into the metal casing. But first I need to make room for the wires to exit this metal case. There are two holes in the plastic part but one of them is in the wrong place. The one at the other end has some kind of ceramic plug in it. If I can drill this out it will make a natural route for a wire. The drill bit is not happy drilling into ceramic, and eventually the plug just breaks out anyway.
I want to add the three required wires now as soldering them in place after the board is in the case is a pain. I need one wire for 5v, so red for this. One wire for the incoming video signal, which will be green. And one to connect the outgoing signal to the video socket. I’ll use yellow for this.
Some big blobs of solder around the can to fix the board in place.
Ahh, I forgot to drill out the plastic hole for the other wire. Now I’ll need to be careful I don’t damage the components inside.
There we go. All the wires are ready and all I need to do now is attach this back to the motherboard. I even remembered the bottom lid this time!
With the modulator can refitted I now need to attach the two wires. Before removing the modulator earlier I took a photo to show where the two wires need to go. There are alternative points on the board for different regions. But this one here is the video signal for the UK. And this one here is the 5v supply.
And with the wires in place it’s time to test.
To start with I am testing without the 555 timer chip to see if it’s required. And look at that. Pretty much the same black screen as before. Only this time connected to the TV’s composite input. And with the 555 chip?
Well look at that! Perfect!
Back inside its case and the keyboard seems to be working perfectly. It’s a nice feeling membrane compared to some I’ve tried. And typing in a 10 PRINT program is a joy that brings back all those fuzzy warm memories.
The last thing to do, seeing as this is such a nice little machine, is give it a clean and make it pretty again. Windex and a toothbrush on this textured surface. And then a wipe off with some paper towel. Yup, that was pretty grubby. Finally a coating of renaissance wax to protect it and bring out the lustre of the black plastic. Oh and a sticker for its eventual owner to remove in disgust!
It’s not a very useful machine, but I really like it. And I hope its eventual owner will appreciate just how pretty it is to me.
Thanks for watching! I will see you in the next one.
Bye!

This #Amiga 600 is broken. My favourite kind! I also look at a new method of removing surface mounted electrolytic capacitors. You may be triggered…

The ugly duckling of the retro computer world. 

Early in 1992 when I was sporting my beloved, but starting to creak, Amiga 500, Yes, that’s me. Commodore in all their wisdom, decided what the home micro computer market needed was pretty much what we already had, only smaller, and worser. The scorn us 500 owners poured on the new Amiga 600 was shameful, but fully deserved. I mean, it had the worst compatibility of the available machines without any meaningful upgrades to the silicon. All of the fancy expansions you could get for your A500 wouldn’t fit, and the num pad was missing! It felt, at the time, like a big backwards step and I, and everyone I knew, ignored it completely. In fact we went a step further and loathed that little Amiga.

So what about today? Did the ugly duckling turn into a beautiful swan?

Well, no, not really. It’s still a duck, but it’s grown into its face now, and in the right light is quite a handsome little wedge. 

This one here is a very nice specimen. Both on the outside, and on the inside. I was sent this computer by friend of the channel Colcuz, who donated it for the charity event I’m running later this year. You’ll be able to buy it and many other very special Commodore machines (and one lone mystery non-Commodore machine) in a huge auction to be run on the 14th of September. I’ll be live streaming with lots of special guests from all around the world of retro tech and gaming youtube for a marathon (for me) 12 hours. Together we can watch the auctions end and see how much money we can raise for the Befriending Scheme. Last year the final total was over £15k and we’re looking to beat that colossal amount this time around. I don’t want to start up the playground wars again, but can the Commodore fans really let those smelly Speccy oiks win this epic battle? 

Inside this lovely machine you can see it’s been upgraded with a few, er, upgrades. Here is an IDE to Compact Flash adapter taking care of hard drive duties. In the trapdoor is a ram expansion, bringing the onboard Chip Memory up from 1mb to 2mb. And here, clamped over the 68000 CPU is a clever board that adds fast memory to the system. And in the ROM socket is an upgraded kickstart 3.1. 

The expansions are not extravagant, but they do turn this into something much more useful in as much as an Amiga can be useful in the modern world. Basically it’s going to be a lot easier to play games on this than your bog standard A500. 

That older, and much larger, machine can be a bit of a faff to use. You need the right Agnus to allow enough chip memory to let you run games from hard drive. Oh, and connecting a hard drive usually entails purchasing something period correct like an A590 to plug into the side expansion connector. Not cheap or ideal. The alternative there is using a Pistorm and mounting hard drive images with that, which isn’t everyone’s cup of tea, or buying an expensive real hardware accelerator with on board IDE. And whilst it wasn’t a problem back in the late 80’s and early 90’s the A500 takes up a huge amount of desk space now. The 600 just fits nicely. Its cute. 

I would go so far as to say that the 600 is one of the best real Amiga’s to own now, here in the future. 

The other best Amiga to own now is of course the Raspberry Pi. 

Now I’ve had a chance to get to know this little dude I really want one for myself. And luckily, a while back, a very nice man called Neil, or Neildo, sent this one for me to add to my own collection. I like to think of this as a blank canvas. There are no upgrades fitted, it needs a good clean, and best of all its properly broken!

So where do we start?

Well I want to start with replacing all of the leaky electrolytic capacitors in here, and I want to try a new method of removing those pesky things. My preferred method is two soldering irons, but last time I melted the plastic on the audio ports which was quite upsetting. So this time I think to reduce the chance of melting anything I am going to use a combination of hammer and chisel. I have some lovely sharp chisels here in different sizes which should make getting into tight spaces quite easy. And various hammers to give me the perfect amount of control. 

Right. Let’s pop the top off and get the motherboard on the workbench. 

Wait a minute! All the caps have already been removed! Oh That’s a shame. Now we may never know how brilliant this hammer and chisel method could be!

Now we have the motherboard free I can show you the problem with this machine. On the back side there are two ceramic capacitors that have burnt up. Properly burned. The board substrate beneath is blackened and charred. These are decoupling caps which sit across the ground and 5v rails. If these have burned then it’s safe to say something bad happened to this machine. Now it is possible it’s just one of them went short, maybe this one here where all the burning is, and that took out the other one. But what’s really worrying is that there is still a 3 ohm short across ground and the 5v rail. So the likely thing is that more of these caps are damaged and causing the high resistance. Another possibility is that whatever happened with these caps also took out some of the precious chips on the other side. The very burned one, for instance, is directly underneath the 68000 CPU. For now I have to work on the assumption it’s just the caps and and with that in mind I took some resistance readings at various places across the board and compared the results, looking to see which side was more shorted than the other. This pointed to something over here on the right side of the back of the board, near to where the burned caps were. My next idea was to inject some low current, low voltage into the board and see what glowed. I took a spare power supply lead, worked out which wires were the ground and 5v, clipped my bench power supply to those, and then set the supply to 1v and 300mA. 

With my thermal camera ready I switched it on… And just down here this cap started to heat up. Not much, I wasn’t putting much power into it, but enough to show there was some unwanted resistance there. The simplest way to sort this out is to start pulling the decoupling caps off the board one at a time until the short disappears. I started with the caps close to where the resistance readings indicated. Ill hand you over to bench Lee to explain what I found.

Right this is where I’m up to I’ve removed three of these decoupling caps these three are off of the other side of these logic chips u47 u46 and u45 and c47 was a 30 ohm short and c46 was fine c45 was 2.8k this one up here which is behind the ROM C6 was 28 ohms and if I

measure across the rails now between ground and 5 volts I’m getting 61 ohms so my guess is that there’s well there are some more decoupling caps dotted around I reckon they’ve all been damaged so I’m going to take all of them off and replace all of them hopefully I’ve got enough 

Have a shave man. You’re almost as hairy as your mic.

Now, I’m not really used to working on this type of board, and I’m still very much learning how to use my hot air station, and so there follows a bit of a mistake.

You see, I started off with the air set to 350 degrees, as that’s usually enough for most things. But the caps were very reluctant to come off. So I assumed that was because the ground points on these caps were sucking away all the heat. But no, what was happening was the caps were hard to remove because Commodore had glued them to the board during the manufacturing process. This is actually quite common with surface mounted components. And it does make removing them a bit of a gamble. You don’t really want to pull too hard in case it’s not really ready to go and you rip a pad off, but you have to break the glue. 

And in the end I managed to delaminate the area around this cap. I wasn’t very happy with myself. That was the point where I worked out what was happening with the glue. 

After this I started taking the caps off with a soldering iron with a large blade tip. That was far easier, quicker, and safer. You live and learn. Please feel free to beat me up in the comments.

I worked my way through all of the decoupling caps on the front and back of the board, around 30 of them, testing the resistance as I went. And eventually with just about all of them off the board the resistance returned to something more in the expected range of around 130 ohms.

The caps in the middle are all still within spec, the 5 on the right are properly shorted at various resistance values. The pile on the left are still capacitors rather than resistors, but the capacitance is now either too high or too low. With this in mind I decided to replace the lot. After all, if these ones had failed, possibly for no reason other than they’re a bit old and rubbish, then the others were likely to follow suit. I ordered a 100 of them and waited for the postie. It’s possible this board is still beyond my ability to repair. If it suffered an overvoltage from a bad power supply at some point, causing those caps to fail, then it’s likely that overvoltage not only took out the caps, it probably took out some of the silicon also connected to the 5v rail. My best chance is it wasn’t an overvoltage, but maybe just one of the caps failed short and the others were just on their way too. The only way to know for sure is to install all the missing electrolytic caps, replace all the ceramic ones I removed, and switch it on to see what happens. So while I wait for the ceramics to arrive I’ll get these electrolytics fitted.

First job is to clean up all the pads. Neil did the right thing removing all these caps, saving this machine from further damage. There are signs of light electrolyte corrosion in a few places. Especially here around the reset circuit. From experience I will need to remove the 555 timer and these capacitors to clean underneath them.
The postie brought me some new 330nF caps and I set about putting them on the board.

And the moment of truth has arrived. Either this board is toast and good only for spares, or replacing with a raspberry pi, or I got really lucky and the only thing wrong was the caps had all gone bad. 

Woo hoo! It works!
Well. Mostly. There’s some glitching going on here with, it looks like, the red signal disappearing from the RGB image. I will just ignore it for now and hope it’s just a settling in thing. 

Some dyna blaster to test. A firm favourite from my old amiga days when I used to take my own A500 to the pub for multiplayer mayhem with my friends. Happy weird days. 

Next job on the list is to get this machine all cleaned up. It’s in a really bad state and I spent an evening stripping all the keys off the keyboard and giving everything a good scrub in soapy water. And underneath all that filth and dust it turned out there was a fantastic little machine in excellent condition! A few of the keys have slightly yellowed but a day out in the sun, with a leafcutter bee for company, evened that out enough for me. 

Now I have a nice condition, working Amiga 600, I need to put a few of those upgrades we saw earlier in the charity machine in this one to make it usable. 

First up is the trap door expansion. On my discord server I have a channel for swapping PCB’s, and I took Nick up on his offer of an Amiga 600 ram expansion to double the chip memory from 1 to 2mb. He also sent some of the smd passives and the clock chip he had as spares. Cheers Nick!
I still needed to source a connector, the battery holder, and a few resistors. Oh, and some memory. I asked again for help from my discord members and Fuzzy Lee offered me an old PC graphics card with the required memory chips on. Thank you Lee!

Getting the chips off this board shouldn’t be too tricky. And whilst it’s likely this card won’t ever be used again I think it’s sensible to do it non destructively, so I’m taping aluminium foil over the plastic bits to protect them.

It’s not a thick board so just 350 degrees and off they both pop. I’ll leave the other two here for safe keeping.

I’ve never worked with this type of chip before, and I hear they are a pain to solder, so this should be a fun learning experience!

I start off by cleaning the pads with IPA. And then adding some liquid flux. This isn’t a good move. Liquid flux tends to boil away very quickly and as I add some solder to the pads it’s not flowing. 

I replace the liquid flux with some better quality paste from a syringe and try again. This time the solder flows perfectly onto each pad.
Offering the chip up it doesn’t want to sit on the now raised pads. This feels like it might be tricky already. My plan is to reflow the pads with hot air and hope the chip settles in place. After a go with the hot air I can see it’s not going to work that way. And so I return to my trusty chisel tip iron and try a bit of drag soldering instead. It seems to work much better. A quick test with a pair of tweezers to see if any of the legs are moving, and I find there are one or two that are still loose. I think this just wants much more solder than I’m offering. Adding more flux and much more solder I go again.

Ok, that went much better. For the other chip I don’t bother with tinning the pads and just tac it in place and then drag along the legs with plenty of solder. Worked a treat. 

It’s nice and simple to see if the legs are properly connected by just testing for continuity between the pad and the top of the leg. Being careful not to push too hard and get a false positive reading. And I do find one leg that isn’t connected. A quick dab with the iron fixes it and all the others test good. A close look at all those lovely solder joints. No bridges and all perfectly attached.

Now, with the chips in place I can switch to the microscope to fit all the SMD passives. 

First up is this relatively large tantalum capacitor. I’m used to silkscreen markings indicating the orientation of components’ polarity, but there isn’t anything obvious on this board to show me which way round this cap goes. Unless that extra bit on the right side counts? I had to go look it up and I found a video that my pal Glen over at CRG had made building this exact same card. He also had to work out which way round this went. I’m still learning all these things and will probably forget quickly anyway, but thank goodness for youtube and amazing channels like Glens. He also showed which way the LED needed to be installed and saved me having to look that up/
Look! I even get my name on the components! How cool is that?

There were a couple of components not listed on the bill of materials, which meant I needed to examine the schematics to get their values. This resistor here for instance at R6 is a 1k. 

I do like SMD soldering, but that’s all done now. Time to fit the other bits.

Edge connector, battery holder, pin header and clock chip all fitted. Will it work? Lets plug it in and find out!

I recycled an old floppy pirate disc into an Amiga test kit disc and booted from that. 

The image is still a bit flickery. I don’t have time to fix that right now so I will probably look at that in another video. Possible on my second channel. But there is now 2mb of chip ram and it all tests good!

The last thing I need to do is fit the fast ram I purchased for this machine. This uses a plcc type socket press fitted over the 68000 CPU. It’s a bit hit and miss with these as to how well they sit on these chips. And this one just doesn’t go on very securely. This other one inside the charity Amiga 600 looks a much better fit and seems very secure. It also just about fits under the hard drive caddy. It might need a bit of metal filing off to make a better fit though. The other one will not fit under the caddy. I’m not sure I will leave this one inside my own 600. If I can live without the expanded memory I won’t use it. Another problem with these fast ram expansions for the 600 is fitting them means the PCMCIA slot doesn’t work. Which makes transferring files too and from the Amiga a lot less convenient.
The only other thing I need to install is a hard drive solution. I have plenty of these around and my friend Matt from the brilliant Tech Made Easy youtube channel kindly sent me a 4gb Compact flash card I can use with this machine. And I have this compact flash adapter which has been sitting in my spares bin waiting to be used for far too long. 

I can see myself using this amiga far more than my A500, 1200 or A500 plus. It’s just the perfect size to plonk on your desk and have a blast of sensible soccer or dune 2. It’s a cracking little machine. 

Thank you Neildo for sending it to me. I will treasure it forever. 

If you want your own amiga 600 you can bid on this one in September. And if you don’t manage to win, I have another one here you can bid on too!! This one was very recently given to me by Andrew Searle who popped round with a box of amazing donations for the charity and the channel. Andrew said this one was for me if I wanted it, but I said I already had a 600 and if he didn’t mind I would put this extra one in the charity auctions for someone else to own and hopefully raise a big lump of money for the befriending scheme!
This one has the notorious reset problem that happens when the caps leak over the reset circuit. I don’t know if it will make it into a video as I not long ago repaired a very similarly broken 600 in a video you can see in the corner of your screen. But the other thing with this machine is it’s very yellow, and I recently bought a big load of peroxide and I might give retrobrighting a go!  Keep an eye out here and on the second channel for updates about some of the amazing things I will have for sale on September the 14th. Put it in your diary! And if you just want to donate you can do so on the Just Giving page which you will find linked in the description. 

Lots more to come getting all these machines ready for you! See you soon!

A Replacement ULA for the Acorn Electron!

It Changes EVERYTHING! (If you have an #AcornElectron with a broken ULA) But seriously, this is an important moment in retro and we should all be really grateful that people like @mogwaay and The Board Folk are giving us these things to keep our systems alive

All your computers are dying!

As we all strive to scratch our nostalgia itch, the effects of time passing on these old machines is a growing problem. Old plastics are breaking down, capacitors are drying out, and components that were never expected to last for more than a few years are spontaneously expiring just when we need them to give us our Jet Set Willy fix. Custom chips can be especially difficult to replace. Popular computers like the commodore 64 and Sinclair ZX Spectrum are well catered for and it’s now possible to build entirely new versions of those micros using brand new parts.

But what about some of the less popular machines?

How about the Acorn Electron? In the UK market this was meant to be the ZX Spectrum killer. And if a young Bilbo Baggins had managed to release it in time for the Christmas rush it might have been a big hit.

For viewers watching from other regions who might not be familiar with the little Elk, this machine was meant to be a cheap, cost reduced version of the BBC Micro.
What’s a BBC Micro? Oh come on America!
Ok, the BBC Micro can be thought of as the British Apple 2. I hope that makes things clear.
Now the thing about the 1981 BBC micro is its one of the few machines, certainly one of the few very successful machines, that you can build from scratch today using all off the shelf parts. Most other machines released after that time were designed with cost in mind, and one good way to reduce the cost of building a computer is to amalgamate as much of the logic as possible into fewer chips. Which is where ULA’s or uncommitted logic arrays enter the picture. The ZX Spectrum ULA combines almost all of these chips here into this single 40 pin package. 

Acorn took a very similar approach when they designed the Electron. A machine meant to compete at the value end of the market, but compatible (partially) with the much more expensive and very popular BBC Micro. 

But is there a risk attached to buying a condition unknown, works the last time I used it in 1986, electron from ebay? If any of the chips inside this machine are broken you don’t need to worry, not at all. All of them are easily replaced, and cheaply too. For example, this LM324N opamp here costs 98p. For ten! The logic is cheap, the ram is cheap, a rom can be replaced with a cheap eprom, and the CPU is a fairly standard 2mhz 6502. Yep. Nothing in here to worry about. What’s that? Oh don’t worry about that. That’s nothing. Just keep looking at all the other cheap chips.
Oh. Ok. Well that would be the infamous Acorn Electron ULA. This chip is, more than any other in here, the beating heart of this little machine. If this goes wrong, and they do, your Elk becomes an ornament. Quite a pretty one I think.

Currently the value of second hand electrons, is there a new value? Is pretty much as low as it will ever be. The last few auctions I can see on ebay sold for around £30. And I think it’s down to this: The risk of buying one with a faulty ULA is reasonably high. And if you have to replace the ULA the current going rate for one of those is around the same £30. Which makes no sense at all. The ULA you buy for £30 could expire almost immediately. It’s a frustrating state of affairs. And something that’s becoming more and more of a problem as they get older.
So what’s the answer?

Well the solution is to recreate the failing old tech, using new tech. As I mentioned at the start, the ZX Spectrum has new chips available, including the notorious ULA in that machine. This was reverse engineered by Chris Smith, and then other clever people such as Don Superfo came along and made a Spectrum that didn’t even need a ULA! There are also, more interestingly for the subject of this video, recreations that drop straight into the same socket. In the spectrums case the VLA82 by Charlie Ingley and the Nebula from Retroleum. But currently there isn’t one for the Acorn Electron.
Well. There wasn’t!
Chris Jaimesson, or Mogway, or Jamsoft, pick a name Chris! Is someone I’ve known through his positive interactions in the retro community, mostly on twitter, and more recently on my discord server. Which you should join. It’s awesome. Chris has come up with something that might be of use in bringing one of these destroyed motherboards back from oblivion. 

Let’s have a chat with him so he can tell us exactly what he’s been building in his techno cupboard. 

Why the Elk?

Well I didn’t have any experience with Electrons growing up we had two BBC’s when I was young and after picking up the nostalgia bug I was like oh I really fancy getting back into the Acorn world. So the first one that you got was it broken? Yes! I picked up one on the infamous Facebook sale where it was on a drive I saw pictures of this driveway covered in electrons and I picked it up and I was thankful the case was in really good condition it was very poorly packed it came in good condition but I had a little peek inside and yes no ULA and then it was Twitter user Scurvy Geek who got back to me and said gave me a little Ray of Hope and said well I think there’s a few people working on ULA Replacements so I kind of thought well could I fill a niche there is there just a bog basic like I just want the elk to be an elk could I just find a bog basic Electron replacement so I thought how hard can it be! But at just at that time I was looking at it I started Eric Schlaepfer who’s known as TubeTime who’s a reverse engineering wunderkind he’s done a lot of great stuff on the PC side of things he released the Graphics Gremlin which was an ISA card which could do CGA and MDA on an FPGA and he open sourced it entirely again and I could basically crib the basic FPGA plumbing from the Graphics Gremlin as my basis to build upon to do my own Spin and add the little bits I needed to get it going on the Electron for ULA so really I’m taking my I’m standing on the shoulders of  giants so I took David Banks’s amazing ULA code and I mixed it with the Graphics Gremlin and stuff and kind of smashed it together and that’s how it came about really.

Thank you Chris. And well done for bringing this project to the community.
Chris has very generously sent me a prototype to build and try out for myself. But before we get into that we need to look at these. 

All four of these boards were very kindly sent to me by Dave Hitchins who some time ago picked up a big score of Electron motherboards and various other parts. These are from a notorious haul of scrapped Acorn Electrons from a Facebook seller not very far from me. In fact my own Electron came from that very same seller. I think the story goes that these are originally  from a repair shop of some sort and many of these boards were scrapped for their parts. Which, looking at the condition of the four boards here, makes sense. When I bought my own machine from that seller it was complete but not working, I made a video about its repair which is probably in the corner of your screen right now. If I remembered. 

To give this new ULA a home I need a board to install it into.

Let’s take a closer look at these boards and try to pick a winner. 

There are three issue 6 and one issue 4 boards. 

The issue 4 board, at first glance, seems to be in the best condition. Only missing its CPU and ROM, IC17, and of course it’s ULA. Although the ULA socket is still here which is a good thing. Meaning there will be less chance of damage in this important area. Unfortunately there is some damage here near the CPU. I think I can resurrect that if I need to. That doesnt look too bad. There’s a missing pad there. I’ve labelled this one board number 1. And so far it seems to be promising. Number 2 is the first of the three issue 6 boards. This one is missing IC19, the ROM, the CPU and the ULA looks to have been ripped from the board. There are bits of metal sticking up and four of the pads are obviously missing. This is low on the list, but not impossible. All of the memory is present, but all of the decoupling caps looked to have been chopped off. I honestly don’t know what’s going on here at the keyboard connector. 

On the other side – well that just looks nasty. A huge glob of molten solder was just dumped here. No idea why. But the back of the ROM and CPU are looking grim and the ULA vias have suspicious bits of leg still hanging on. 

The top of board 3. The keyboard connector is the same grotty mess, the ROM is here! That’s a bonus. The CPU is missing, and at first glance there don’t seem to be any missing or ripped traces. The RAM is all missing but it seems to be neatly done. And the ULA is no longer there, but there seems to be less burning and devastation. And the back? Well this could clean up. There are no obvious missing pads or traces. But that green inner square of the ULA area does look a bit suspect. I wonder if this has delaminated. This one is on the maybe pile.

Board 4 is quite similar to 3. It has no ROM, but it does have all the RAM. Someone really didn’t like ceramic disc caps, did they! Maybe rats ate them. And the other side looks like it could be a winner too. I can’t see any obvious damage, but like all the others I will need to clean up and give all of these a thorough inspection before I decide which one to bring back.
And hopefully we have a candidate for resurrection. 

In the end I narrowed it down to board number 3. Even though it has this delamination it doesn’t seem to be affecting anything important.  the rest of the board looks in very good condition after a bit of cleaning.
I removed all of the chips, testing them all outside the board in my TL866 minipro programmer, which is not a perfect test, but should show up anything totally broken, and replacing the grotty keyboard connector, and then installed sockets in all the places where the chips needed to go. Just in case. 

A few passive components needed to be replaced. I borrowed these along with a set of memory chips from one of the other boards.

In the ULA position I used strips of turned pin headers to create a socket. And to make sure it was the right size and shape I did in fact desolder my own ULA to use as a guide, holding the pin headers in place whilst I soldered.

I switched it on with the original ULA installed and it worked!

So that’s a working board that’s missing a ULA.
Now we get to the interesting bit! Is it possible to build a working ULA using all these parts?

I’m a big fan of SMD soldering, but I have to say I was a little apprehensive to say the least when I saw the size of the components and how close together they are on the board. These are mostly 0402 parts, which means they are 0.04 inches long and 0.02 inches wide. Here is a banana for scale… 

Ok, something more sensible. Here is a normal quarter watt resistor.

Even with eye magnification I can’t reliably see these sized parts well enough, so it’s time for my trusty microscope. I say trusty, I actually lost quite a lot of footage recorded on the scope. Including all of the chip soldering, so not as trusty as I would like, but the work went pretty smoothly overall so you didn’t miss too much on all of the fun stuff. 

The kit Chris sent over comprises of 2 boards. The lower board is the one that has just a few components needing to be installed. I thought it would be a good idea to get my practice in on this board before turning to the top board where there was a lot more to do in a much tighter space. And being aware of the tiny scale of things here I switched to a tip I don’t normally use, hoping it would give me more precise control. I see lots of skilled technicians using these witches’ nose tips, and I just don’t know how they do it. I found it quite frustrating to use. Normally with a chisel tip I can control where the solder will be on the iron, but with this one it just doesn’t like to be near the pointy part of the tip. And being round I couldn’t get it to touch the pad and component at the same time. Before too long I switched back to my chisel tip and found that much easier to use, if a little bulky. In fact with some of the components I found it easier to flow some solder onto the pads first and then just blast it with hot air.

This bottom board carries lots of heavy traces, especially the ground and 5v points. This capacitor here refused to attach at the end close to that via. The solder flowed nicely onto the end of the cap but the iron couldn’t carry the heat into the pad. 

It looks soldered here, but if you look carefully you can’t see any shiny solder on the pad. And heating the other end? It wasn’t attached. I grabbed the heat gun and blasted it with 400 degrees hot air. Something I would need to do quite a few times further into the build.

These castellated resistor arrays were to prove very tricky. There’s just the one on this base  board but you’ll see a few more on the top board. And they gave me quite a few headaches.

I assumed they would be reasonably simple, a bit of drag soldering on both sides and job done. 

But that big heavy plane of copper to the right joining all four of the connections on that side was just sucking the heat right out of my iron. It was all a good learning experience though. 

Let’s try that again!
This time I want to get some solder onto the pads before attaching the part. That can help conduct the heat into the board. Two of them just don’t want to take the solder though, so I have bumped up the heat on the iron to 400 degrees. That’s got another one. And. Oh that looks a bit messy. Yeah, it’s not improving the more I try. Flux will sort this out though. Again with the hot air gun.

You can see the solder flowing and then instantly freezing again as soon as the air is not pointed right at that spot. I’m not sold on this one being attached so here is my multimeter in continuity mode. And testing from the top of the connections on the resistor they are all connected on the tricky side. 

As I said, all of the footage of the chip installations was sadly lost. But you can see the chips in lots of this footage and they are all perfectly installed. I checked each pin was securely attached, and tested between all of them with a multimeter, checking for bridges.

More resistor arrays. I’m getting a better flow going (ho ho). Although that pad under the 5 on RN1 here looks suspect. We might come back to this later!

That’s all the components fitted. 

Chris informed me this version of the board would require a couple of small bodges to work correctly. These have already been fixed in the most recent updated version. I just need a couple of wire links… and a capacitor. And one big chunky resistor over here on the side.

Next I went around every part of the board checking for shorts. I checked all the legs of the chips again, and all of these resistor arrays. I checked between ground and the various power rails and found no problems.

With the soldering completed I moved on to programming the FPGA. A process I’m not familiar with or comfortable explaining in detail here. Rest assured Chris has a comprehensive guide for all of this and more on his repository (link in the description). There are certain types of programmer that you can buy which make this process fairly simple, just a few command line commands and files in the right place to start with. I ordered one of those programmers from Amazon. Amazon delivered something totally different, I think these are stepper motor drivers. Chris said “don’t worry! I will order you the right thing and get it delivered tomorrow” A package arrived the next day from Amazon. Aaaaaand it was the stepper motor thingies again. He’d ordered the same thing I had!

And so we stepped into the murky world of Linux. Or at least that’s how it feels to me. I appreciate it’s a wonderful operating system and can do so many incredible things, is super stable, reliable, mostly free etc, but that doesnt mean I know how to use it.
Chris found a way to program the FPGA using a raspberry pi. Something he then added to his repository to help anyone thinking of building one of these. A proper programmer will be a simpler process, but to help keep costs down you can use just about any pi you have laying around. He actually did the testing on the original Pi 1. I had a few pi’s to choose from but thought having a keyboard already attached would be helpful so I opted for my pi400. 

Using the guides from Chris’ repository I attached the pi to the programming connectors on the ULA board. As I didn’t have the right gendered wires I ran them through a breadboard to the GPIO pins on the back of the pi400.  Then I double checked those connections. Then I checked them again. I installed Raspberry Pi OS and started following the guide Chris had provided. Then I got immediately lost and, close to fake tears, I messaged Chris asking for help. Chris is a brilliant bloke and spent a couple of hours guiding me through the process one command line at a time. And in the end we did it! 

It was finally complete!

Excited, I plugged it carefully into the test board and switched it on. 

My bench power supply immediately complained and went into voltage limiting protection. 

Oh no!

Was it something I did? I switched the FPGA board over to my own issue 4 Electron in which I’d already fitted some pin header strips for the original ULA. And this time it didn’t current limit. But it also didn’t work.

Some hours were spent pouring over both the now broken Electron motherboard, and the sadly non working ULA replacement.

On the issue 6 motherboard it took an embarrassingly long time to work out that a tantalum cap had given up and was shorting out the 5v rail directly to ground. A bit of measuring the relative resistance with a multimeter and finding out which side of the board was more shorted than the other pointed to this cap here. Removing it removed the short, and replacing it brought the electron back to life once more. 

But the ULA was still not working. 

During a very busy few days I went back and forth with Chris during snatched moments of time, with him feeding me clues on what to look for and where. Eventually, after a few red herrings, we found that two of the data lines were missing altogether, and using his excellent schematics I followed these lines from the FPGA, through the level shifter next to it, and into these resistor arrays. That’s not connected. Yep. Those pesky resistor arrays. Checking for continuity with the nearby pins I found one of them was not actually connected. I gave it a careful reflow and checked again. It still didn’t work. Well, chances are if one of them was not connected then others could be the same. I checked every connection from all of the resistor arrays around the board and found that quite a few of the connections were not making it through. There’s probably a better way to make these flow but in the end I got there with my chisel tip iron and hot air station. 

And then?

It’s working!

The case is beautiful it’s such a lovely little machine so I’m really hopeful that some of those can kind of come back to life and give people enjoyment. Secondly I’m also hoping that if an idiot like me can build one of these things then you know there’s hope other folks that might be inspired to give it a go too

So now what?

Well before I get to testing this I want to look at what I have here. This is my Acorn Electron I’ve had for a while now. It works fine, has an original ULA inside, and I don’t need to do anything with it. This Electron I recently bought from Julian from my Discord. It has a lovely case, in good condition, and the best thing about it is it doesnt work. This is going in the repair pile, and Im hoping it wont need a new ULA but if it does, well we know how to fix that now!
These four boards are a problem. I’ve already brought this issue 6 back to life, and the issue 4 should be fixable with a few bodge wires around the CPU area, but what about these other two? This one (number 4) is in pretty decent condition, just missing a load of decoupling capacitors. The board itself is pretty good. But this one…the aptly labelled number 2, has some heavy damage around the ULA area.. Its had a hard life. 

It’s all fixable. But there’s quite a lot of work here and in the end I would need a ULA, a CPU, a ROM, all the RAM, all these caps, and I would still only have a working board without a case to put it into. The case contains the most important part you need when using a computer, which is, of course, the keyboard. But is there another way? 

Well yes, there is! And as a bonus there’s something I can do about that destroyed motherboard too…

This is a PS2 keyboard adapter for the Acorn Electron. Kindly sent over by its creator Ian, who goes by the name GrandOldIan and is one of the brilliant group known as the Board Folk. This turns a bare board without a case into a pretty much fully functioning Acorn Electron. Albeit a bit nude and without a proper power supply. You can run an Electron just using a simple 5v power supply, but for tape functions you need the -5v that the original supply, er, supplies.
Ian also included a bare board so I can make up another one of these. It’s super clever, just slotting over the keyboard pins here. And you can still have an original keyboard connected with this set of pins here. The modulator, which is much less useful than it used to be, needs to be removed and the PS2 connector sits in the space where your RF cable used to plug in. It’s a very neat and clever device.

As well as the PS2 keyboard connector Ian sent this. 

This is an issue 4 recreated motherboard. The Elk. Again, from the marvellous Board Folk. I believe credit is due to Rob Peepo Taylor, who has been involved with many amazing board recreations. This one is an early version they’ve tested and works. It doesn’t include any credits to its creators on the silkscreen, but they kindly allowed me to give it a look over.
I intend on taking the worst board, that last issue 6 we looked at, and transplanting all of its parts over into this board. But that will be for a future video.


Right. Now I have a working ULA replacement in my rescued Acorn Electron, and a clever PS2 keyboard.  What can I actually do with it? Well pretty much everything you can do with a standard Acorn, plus a little bit more!

I don’t have a fancy SD card loading device for the electron, but I can load games via the tape port using my TZXDuino. Here is one of my favourites – Chuckie Egg. You might have seen Adrian playing this classic on his recent Electron video. 

And here is a very interesting one. Zalaga, which might be a clone of a game with a similar name… is a really good looking game by Nick Pelling and I really got into the blastemup action. But there’s something going on here that isn’t quite right. When things get really busy it looks like there are frames being skipped. It’s not really hurting the fun but Chris has come up with a clever fix for this. 

FPGA chips come with something called BRAM, or block ram. Only a tiny amount in modern terms, 8k in fact, on this particular chip. Which happens to be a rather useful amount in the context of a machine with just 32k of usable RAM. So when you press a combination of keys, in this case Ctrl Capslock and 2, turbo mode is activated.
Turbo mode uses that 8k of BRAM on the FPGA and maps it to the first 8k of address space on the Electron. This duplicates the effect of a retro hack from back in the day called the Slogger Turbo. That one did clever trickery to shadow the lower 8k of memory, allowing the CPU to access it at its full 2MHz speed. On top of this the 8k inside the FPGA is a full 8bits wide, unlike the 4bits of the real ram on the motherboard, so even more performance is gained. There are other things involving the way the ULA accesses RAM for display purposes that I really don’t fully understand, but these also give performance boosts. If you really want to know more about this stuff you should watch RetroBytes John’s excellent video on the Electron in which he explains everything about the Elk in his usual brilliant way. “Remember when I said I’d come back to Ram well this is the moment where we’re going to come back to Ram” Or go ask Chris. He will pretend it’s all very simple and be all modest but the man is basically a raving genius. His explanation for my simple brain was “It’s like fast cache ram on PC”

The results of pressing the turbo mode combination keys is quite startling. The game runs slightly faster in general, but when the action starts to get really busy the dropped frames become far less of a problem. They’re still there, but it doesn’t affect the gameplay now. And what a great game! This had me laughing like a loon! It’s made a fun but slightly glitchy game into an insanely fun and still a bit glitchy game.

I’ve tried a bunch of games on this replacement ULA and, for me, it has performed flawlessly. There are bound to be some edge cases that make it fall over but this is a brand new thing and I’m sure others will take it even further. 

It’s been a fantastic project to work on. Thank you Chris for letting me loose with your amazing widget. I had great fun building it and the satisfaction of bringing a scrap computer fully back to life just can’t be beaten. 

I hope you enjoyed the ride as much as I did! Thank you for watching. I’ll see you in the next one! (you are subscribed right?) Bye!


The Final 2023 Charity Auctions are LIVE!

The story of the Missing Speccy is a long and convoluted one. Actually its not that long. In fact its a 23 minute video. You be the judge.
Anyway! It’s now time to sell it again. And its gained a friend!
There are TWO auctions running this week, and at the end of them I will do a little live stream to cover the ends of the auctions so we can tally up the final score. And maybe kick off this years event at the same time!
Here are the auctions for you to peruse and bid on.

First up the Missing Speccy. This has been around the world! A bespoke, custom hand built machine with all new parts, in a beautiful case and including new tape deck and new games on cassette.

https://www.ebay.co.uk/itm/256499425672

And the other auction:
A lovely ZX Harlequin 128k in an original case which includes a NOS faceplate that has never been used. Also included is a new PSU and brilliant quality Harlequin RGB cable from Retro Computer Shack. All of this in an original box with original manuals. Wonderful!

https://www.ebay.co.uk/itm/256499431713

Replacing a Unique and Bespoke Charity ZX Spectrum Computer

The tragic tale of a poor “ZX Spectrum Special Bespoke Charity Edition” which was never delivered to its intended owner by eBay. In which we find out how this terrible event unfolded and how the catastrophe was finally put right. Also I build a cool Harlequin 128k on a very cool motherboard in a super cool translucent case. Its cool. And the first news about this years Commodore based charity event! IF YOU WOULD LIKE TO DONATE! You can still do so here: https://www.justgiving.com/page/morefunmakingit With thanks the  @RMCRetro  for permission to use beautiful b-roll from the Befriending ZX Spectrums episode: https://youtu.be/PniNI7hcn3E Thank you to  @PCBWay  for supplying the motherboards And thanks to Chris for the correct revision board too!

eBay lost it! This beautiful custom hand-built bespoke computer. That all sounds a little bit dramatic and it is. It’s a bit of a tale and in this video I’ll try very hard to put right this terrible wrong. But first let’s go into exactly what happened and to do that we need to go back. Back to late summer 2023. Those of you who follow the channel might be aware of the big charity event I organised at the end of last summer but for anyone catching up the short version is I auctioned off loads of very special Sinclair ZX Spectrum and related items to raise money for the befriending scheme. Amazingly we managed to raise over 13,000 pounds, a stunning amount which I’m still having trouble absorbing. Of all those spectrums I built and repaired for the event this one was my favourite. This brand new 48k spectrum in its gorgeous translucent smoked case with white keyboard and purple motherboard sold to Andrew and Sarah all the way over in the US for the incredible sum of 680 pounds. I packed it up, double boxed in its extra sturdy flight case, paid extra for super insured postage and shipped it off. This was my first time using the eBay global shipping program and when I received a notification the package had been delivered, I crossed it off my list of things to worry about and moved on. But that’s not where this story ended. That notification meant the package had been delivered to the eBay warehouse here in the UK at which point my responsibility for the item ended. eBay flew it over the Atlantic and handed it over to UPS who then promptly lost it. Our generous buyer Andrew after checking the tracking and seeing it was showing the item stuck contacted me to ask if I could help chase it down. The eBay seller tools were pretty useless so I jumped on Twitter and made a fuss there and in no time at all a representative contacted me looked into the case and miraculously it started moving again almost immediately. Apparently there was some documentation they claimed was incorrect and this had caused it to be held up. Nothing to do with me I should add as I mentioned the shipping was being handled by eBay so we waited another few days and it refused to move. Just repeated import scans a couple of times a day. At this stage if Andrew reports it undelivered then eBay will refund him all of the money back and they would then never deliver the item. I was also concerned about where that would leave me. Would that mean they would ask me for the money back too? I asked that question and they assured me this was not the case and because I’d shipped it safely to eBay in the first instance the money raised for the charity was safe. Meanwhile Andrew was still reluctant to report it lost as that would mean he would lose any chance of receiving the spectrum he’d rightfully won. We waited as long as possible but there are only so many days eBay will protect a buyer’s purchase for and that time was starting to run out. The package was frustratingly refusing to move with multiple import scans a day. Andrew reported it missing. Now to give eBay the credit they’re due neither I, the befriending scheme nor Andrew, lost anything in this transaction. eBay swallowed the whole cost and refunded all of Andrew’s original bid his postage fees and import duties. I wasn’t asked to give any money back either. I cheekily asked eBay if there was any chance we would ever see the package again and their answer was a definite flat no. They explained if it wasn’t damaged or destroyed it would be sold off to recover their own costs. So that looked to be the sad and disappointing end to the story. Well no not quite. The thing that really stuck in my throat about this was knowing Andrew and Sarah had missed out on the spectrum they’d rightfully won and being amazingly generous and lovely people they were ready to send back the 680 pounds when they believed the befriending scheme was going to miss out on all that money. So I hatched a plan. To make it up to Andrew and Sarah I offered to build a replacement spectrum a better one more suited to someone living in the States and to be honest the original one was not that well suited. The tape player would not have worked there being 220 volts and I have no idea what the PAL composite signal would have looked like although the HDMI converter included might have helped with that. Essentially it could have ended up being a lovely translucent plastic 680 pounds paperweight. They agreed and generously sent over the money for me to use to make the best spectrum I could with one or two design choices to work around. The remainder of the cash would then be given to the befriending scheme once the parcel was packed up and sent off to live with Andrew and Sarah in the US. So I went shopping. The first conversation we had when deciding what to build was about the case. I suggested a Lee Smith design ZX Metrum and whilst Andrew and Sarah did like the Metrum it wasn’t the one they chose to bid on in the original auctions. They like myself had a favorite. So the case would need to be the same as the lost one. This was a nice easy start to the build as I could just order the exact same case from the excellent ZX Renew and know exactly what to expect. Isn’t it gorgeous? The next box to tick was the motherboard. This would need to be purple. This wasn’t quite so simple but I’ll get into that in a minute. Other than that as long as it was a ZX spectrum of some description I could go wild. To solve many of the problems with using it in NTSC and 60 hertz land I chose to go once again with a Harlequin. But this actually posed a slight problem. A purple problem. The single best way to buy all of the parts needed to build a Harlequin is from Ben at Bike Delight as all the mucking about with bills of material is done for you. But the motherboard that’s included with that kit is not purple. It’s black. Okay I thought I’ll grab the Gerber files and head off to a handy PCB manufacturer who can fag me a bunch of purple motherboards. Well no you see the Gerbers for the issue 2D revision Harlequin are not freely available. Not as far as I can see on the Don Superfo GitHub. On there you can click on a link and that will take you to PCB way and you can order that way. This means that quite rightly Don Superfo gets a slice of the cash generated from his hard work designing these boards. The problem is there are only links to the 3H, 4A and 4B revisions. The components in the Bike Delight kit are intended for the earlier 2D board and there are quite some differences between the revisions. Ben does sell the kit without the motherboard so I ordered that anyway and plan to use it as a starting point filling in the bits that were different or missing as I went along. Speaking of PCBs I need to say a quick thank you to PCBWay. No this isn’t a sponsor spot I’ve not been converted but PCBWay did offer to provide the boards for this project for free. That’s quite a big chunk of change saved that will go to the charity fund at the end. So thank you Elaine for helping out and thank you to PCBWay for not sponsoring this video.

The boards were ordered and quick as a flash they arrived looking glorious and purple. More on the motherboard shortly. That bit of the story isn’t quite over yet. The next problem to solve would be the loading mechanism. The original lost spectrum included a brand new tape deck with some brand new games on audio cassette. That was the part I was concerned wouldn’t be usable in America. Well this time we went a bit more modern with a fantastic Div MMC future from Rod at the future was 8-bit and to match the design aesthetic I managed to grab one in a white case. A smoked grey case with its cool white keyboard and faceplate. A white Div MMC future. A purple Harlequin 128k. This is looking like a pretty sweet package. Probably a good idea to put it all together now. The one thing I was really not looking forward to was piecing together all of the parts I would need to make the latter revision Harlequin motherboard work with the kit bought from Bite Delight. Well fortunately for me I didn’t have to. Chris, one of the brilliant volunteers at Neil’s RMC cave museum, had previously helped with the charity efforts by donating one of the infamous Heba flight cases. He’d offered to donate another one but this time I declined as sending one of those overseas is kind of expensive. When he heard me complain about the different motherboard revisions on a previous video on my second channel he jumped to the rescue offering the correct revision motherboard in the perfect purple colour. So I’m ready to put all this together now and don’t worry not only does this tale have a happy ending it also has a twist but I’ll save that for later so stick around if you want to know what happened next. Time to put this Harlequin together. As usual Ben has done an amazing job of making this process as painless and enjoyable as possible. The instructions are easy to follow and the parts are all bagged up with labels. This will be my third Harlequin build so I should be getting pretty good by now. One thing I will need to do first before I get started on the packets of passives is fit this AD724 video encoder chip. This takes the RGB signal and converts it into either a PAL or NTSC composite signal. It’s also the only chip on here that is surface mounted with all of the others being chunky through-hole and normally if you buy the full kit from bike to light with its black motherboard this chip would already be fitted so if surface mount soldering is not your thing you need not worry. Personally I really like surface mount soldering I think it’s actually easier than through hole. Takes a bit of getting used to and you need the right shape tip on your iron. Okay now the diodes. I’m following the instructions to the letter on this build even installing the optional parts. On my last build I didn’t install one of the resistor packs that is marked as optional and that resulted in a lot of head scratching when it turned out it was not actually optional but simply fitting it fixed the issue. Then the resistors. A request to Ben at bike to light is for an interactive bill of materials or i-bomb that would make this so much easier. A million sockets are sold and in place next. I’m using my new fumic structure that fuzzy lee dropped off for me. A handful of transistors. A bunch of capacitors. Some headers, connectors and switches. And finally a whole load of chips. So many chips. Care should be taken when inserting these you don’t want to put them in misaligned and it’s super easy to bend over legs if you’re not paying close attention. I’m gonna blame my filmmaking at the same time for my mistakes. Once the last chip was inserted I plugged it in and gave it a test. Safe in the knowledge I’d done this a few times before and forgetting that two out of the three times they didn’t work on the first power up. Well make that three times out of four. I was greeted with a garbled screen. Well that’s okay maybe I’d missed a component or put one in the wrong position. I checked it against my own harlequin. No missing components and they were all correct. Or maybe a chip was in the wrong way around or in the wrong place. I checked against the schematics. All the chips were in the right way and in the right sockets. Could it be a bent pin? I took all the chips out one by one and found two bent pins. But when I fixed them it was still broken. Could I have missed soldering one of the pins on a socket? I’d done that before. I checked wearing my head mounted magnification and then again with a microscope. I didn’t find a single unsoldered leg or stray piece of solder bridging anything. I searched the internet for other similar faults and nothing was conclusive. Mostly going over what I’d already checked. In desperation I took all of the chips off of this board one by one again and put them in my own harlequin and they all worked perfectly. I’d wasted a day’s tinkering by this point and walked away to clear my frazzled brain. I came back sometime later and gave it some thought. All of the components are there and in the right positions. There are no bridges in the places I’ve been soldering. All of the silicon is working. It’s unlikely but not impossible that one of the passives is faulty. So what’s the most likely thing that could be wrong? Well the most likely thing is I did something wrong and the most likely thing I did wrong was miss a pin somewhere. I set about searching the back side of the board again looking for that hidden fault. Ever hear the expression you can’t see the wood for the trees? Well it turns out I’d not missed a single pin. I’d missed a whole chips worth. Actually it did have two pins soldered, enough to hold it in place but I’d forgotten to solder a whole bunch of pins on one of the sockets. I soldered them up, plugged it in, switched it on and it’s spring to life. Phew! And here it is completed. The harlequin is an incredible piece of electronic design fitting so much logic into the exact same form factor as the original rubber key ZX spectrum is an incredible feat and all done using off the shelf parts with no custom silicon required. Now before I can put this motherboard into the translucent ZX Renew case I need to make a few modifications. This is the scary bit. Getting this wrong will mean buying a whole new case. The only change needed is an opening for the RGB socket. First with the motherboard inside the case I roughly mark where I want to cut and then cover the area around it with some blue tape. This will make it easy to see where I need to cut and at the same time should hopefully protect the surrounding area from damage. I could drill away some of the plastic but getting that perfectly square is tricky with a perfectly round drill bit. So instead I’m falling back on my woodworking skills by sawing straight lines down close together then using a sharp marking knife and a steel rule I score a line across the base of the cuts and snap off the bits of waste plastic. That leaves me with a rough edge I can fit on with a file down to the tape line. With both sides cut out and the two halves together I can check the hole looks nice and square. Well that looks factory to me and with the motherboard inside it looks even better. Now I can fit the keyboard membrane and screw it all together. I did actually put this face plate in slightly the wrong position which made the keys on the top row stick. I fixed that now and it all works as it should which just leaves some testing to do. Plugging in the Div MMC I can load up one of my favorite games and enjoy this beautiful replacement ZX Spectrum. Stop! What? Stop stop stop stop stop. That’s not the end of the story. Whilst it’s lovely that Andrew and Sarah will now get their super speccy and it’s also really great that the befriending scheme are going to get the balance of the 680 pounds. I still need to do the final maths on this and I’ll share that info in a future update. It’s a crying shame that the original machine that lovely 100% almost brand new ZX Spectrum built to the original specification using all modern parts will never be seen again. There won’t be another machine quite like that in the world. In its beautiful smoke translucent case with white keyboard from ZX Renew and a brand new tape deck and the brand new games on tape. A crying shame.

But wait! Here’s a twist. A little while ago my good friend Paul Universal Retro Boss who is always lurking on eBay snapping up Sinclair and Commodore bargains messaged me with a simple picture. I checked the listing. My hands shaking. It was indeed the missing spectrum. The seller was using my original listing with my photos and the exact same description that also included the words “All proceeds from this auction will be donated to the befriending scheme.” Now this is all guesswork and supposition but I think what happens is enterprising entrepreneurs buy up pallet loads of random items from eBay. Items that eBay were unable to deliver for instance. The buyer then breaks up the contents of the pallet and sells them off individually to try to make a profit. Sounds like a good idea for a million YouTube channels. Clearly this seller was using some kind of automation to list all of the items from a pallet they’d bought in these liquidation sales. I immediately contacted them and asked them to either agree to give the proceeds to the charity or change the listing which they did. They also agreed to remove my logo from the main cover picture. So now what? Well it’s back but the opening bid was £300. I would estimate that the value of the whole kit if you bought it all new would probably be up close to that value so I wasn’t sure of the best way to proceed. I spoke to a few channel supporters and some other YouTuber pals and we decided to club together to try to win it back but I was adamant that the money would not be wasted. The total I was willing to put into this from our little syndicate would be £300. So no wiggle room here basically just the opening bid. I contacted the seller and asked if they were open to an offer and they declined saying that they wanted to see the auction complete. Fair enough. That certainly reduced the chances I would win the auction. I was basically counting on nobody else bidding. I did make a cheeky video and requested on social media asking for nobody to bid against me and then I waited waiting for that last 20 seconds of a nine-day auction to count down so I could drop that £300 snipe bid in there and heart hammering in my chest I would win back this special machine except that’s not what happened. A few days before the auction ended I checked to make sure there were still no bids and oh no. I’d saved the eBay seller and checked their profile to see if this missing listing was just a one-off. Maybe someone had made them an offer they couldn’t refuse but no all of their many listings were now gone. I can’t say for sure but it looked to me like their account had been suspended for some reason. Our special machine was gone again. Well we gave it a good try. Maybe it would surface again one day. Or I did notice it was still possible to message the seller and before I gave up entirely I contacted them asking if the item was still for sale and then I walked away not really expecting to hear anything positive. “You’ve got mail.” They replied it was still for sale. How much do I want to pay? Well I want to pay nothing but I do understand they bought it fair and square and I knew an insultingly low offer would probably kill off any chance I had of seeing the spectrum again. £300 is what we had raised to buy it back so I decided to go with that amount. It was their original opening bid and it was also about what I thought it was worth to buy again. I thought it was a fair price. I replied and offered them £300 with low expectations and they agreed. They said it would appear shortly on a friend’s account and then I could buy it now for £300. I quickly went round my cabal of amazing friends and gathered up the required funds and snapped it up. And here it is. They even sold it to me with free next day delivery postage. Having a look inside it’s all there minus the sweets. The trip around the world didn’t cause any damage thankfully and it’s very good to see it safely back in my workshop where it was born. But what now? Well as much as I would love to keep this lovely thing the whole purpose of this exercise is to raise money for the befriending scheme. So it’s going up for sale again. I’ll be hoping for a more successful outcome this time and while I will make this an international auction I would urge you generous people that live in other less electrically compatible lands to think twice about buying this. As I said at the start the tape deck will not work in the US and the video output for the spectrum will need conversion. Ideally someone in the UK will give this a good home. Due to my current family circumstances I’m unable to run a big event or host a live stream to promote this so I’m relying on all of you out there to get the word out about this one. If I’m able I will live stream for the final countdown of the auction so you can at least take part in seeing how well it does this time. I’ll aim for the auction to complete on the 5th of May but if that changes for any reason it would be nice to sell it on a fee free weekend to save some charity money. I’ll pin a comment here in this video. I will also be promoting this on social media and especially on my discord. All links will be in the description. Good luck bidding! Oh and a last minute addition thanks to the generosity of Super Channel supporter Andy Taylor who snapped up a bargain Harlequin kit being sold on my More Fun Making It discord server and offered it to me to sell for charity. So I’ll build this other kit and install it in an original case making the same modification to the back for the RGB port and this will be up for auction at the same time. But that’s not all I’ll be doing for charity this year. These spectrums are just a little appetizer and a moose boosh if you like. Not long after this sells we’re going to do it all again. Later in the summer, assuming my life has stopped being a slow motion car crash by then, I will be organising another charity event along the same lines as the last one. But this time it’s Commodore! I already have amazing pledges for incredible and unique items I’ll be able to build, fix or just sell to raise another big pile of cash. Hopefully there will be a series of videos featuring some of these machines being made ready and all of this will culminate in a big live stream with lots of special guests and me slowly losing both my voice and my mind. Which seems like fun! As a little teaser one of the machines will be a hand built by me. Amiga 500 using one of these very special Amiga 500++ boards designed and kindly given to me by Rob “Pipo” Taylor. I have a couple of battery damaged 500 pluses to harvest parts from and hopefully we can make one really nice machine from all of this to put up for auction. I also have this C128 you might have seen in a recent video on my second channel. This is the one I’m using the community to crowd fix with everyone giving me their suggestions on how to fix the strange fault. This belongs to my friend Paul Universal Retro Boss and he’s really kindly donated it along with its power supply, a disc drive if I can fix it and a load of games on discs. I’ll make sure it’s all fixed before the auction as well. There will be various other youtubers running their own mini auctions at the same time in different regions around the world. Plans are currently in the very early stages but I can tell you there are at least two Commodore 64’s going up for sale in America and one of them is a very special silver label with a low serial number and it’s a beauty. More details on both of those and hopefully more international sales to come. If you’d like to help out in some way please get in touch. You can reach me via email which you can find in my about channel section and YouTube or come over and join discord and get involved. That’s it for now a cracking outcome and even more money raised for a great charity. Thank you for watching. Bye!

HAKKO vs Duratool

You know the desoldering moo stations? Want to know a bit more about how the cheap option stacks up to the more expensive brand? #Duratool vs #Hakko FIGHT!

Samsung SyncMaster 940mw Repair

In this video, I show you how to repair a Samsung SyncMaster 940MW TV by replacing the capacitors in the power supply. This TV is a great choice for retro gaming enthusiasts, as it has all the inputs you need, such as VGA, DVI, S-video, and composite. You can use it to connect your old computers and consoles and enjoy the nostalgia. The Samsung SyncMaster 940MW is a 19-inch LCD monitor with a built-in TV tuner and speakers. It has a resolution of 1440 x 900 pixels and a refresh rate of 60 Hz. It was released in 2006 and received positive reviews for its picture quality and versatility. However, some users reported that the TV would not turn on or would shut off randomly after a few years of use. This is a common problem caused by faulty capacitors in the power supply board. If you have a Samsung SyncMaster 940MW TV that is not working properly, don’t throw it away. You can fix it yourself with some basic tools and skills. All you need are some replacement capacitors, a soldering iron, a screwdriver, and some patience. In this video, I will guide you through the steps of opening the TV, identifying the bad capacitors, desoldering them, and soldering the new ones. You will be surprised by how easy and satisfying it is to repair your own TV. I hope you find this video helpful and informative. If you do, please give it a thumbs up and subscribe to my channel for more videos on retro gaming and electronics. Also, feel free to leave a comment below if you have any questions or suggestions. Thanks for watching!

MEGA Donation with Rare and Unusual Items!

John who used to work at the Thorn EMI factory where they manufactured ZXSpectrum 48k’s and SinclairQL’s dropped off a haul of riches and wonder. Including a very rare, possibly unique QL motherboard and a ZX Spectrum with a controversial mod.

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