Restoring a Rotten Amiga 600 – Retrobriting – Bad Caps – Pad Replacement – Broken Traces
I’m in the incredibly fortunate position to be offered some very generous donations. Part of being a big deal Youtuber with over ten thousand subscribers maybe?
I don’t know how to put this, but. I’m kind of a big deal.
One of these incredible donations came from the lovely Andrew Searle, who contacted me to offer an Amiga 1200 for this years charity fundraising project. (much more on this machine in an upcoming episode! Its going to be very interesting!
Andrew popped over from somewhere on the other side of the country and delivered, in person, a veritable pile of cool stuff.
This mini amiga for instance. Will be in the auctions too! (October 19th, put it in your diary. 12 hour live stream, special guests, charity fundraising to help buy miniature donkeys! Details about the charity event at the end of this video))
As well as the Amiga 1200 Andrew handed over a working Amiga 600.
He also gave me this! Now this was actually for me.
Well as much as I like getting free stuff I already have an Amiga 600 and it would be very greedy of me to accept another one. So this one is going into the charity auctions to raise money to help buy those tiny donkeys for the Befriending Scheme.
As you can see here, it’s quite yellowed. I’ll try to do something about that.
Inside is a fully equipped Amiga 600, with compact flash hard drive storage, a 4mb fast ram expansion sitting on the 68000 CPU, and a 1mb chip ram expansion in the trap door with a battery for presumably the real time clock.
It’s a cracking machine and worthy of a good home. But it also seems to work just fine, so why are we here today?
Well how about a little bit of restoration?
This A600 was donated by Colcuz Colin. The insides were restored by the brilliant Retro Passion, who, by the way, offer a great service if you don’t want to do it yourself, and quality parts if you do fancy having a crack at retro repairs. You can find a link to their website in the description. No affiliation! I just like them.
The outside of this Amiga was restored by Colcuz himself. I believe he used peroxide creme, something I have dabbled with in the past with a Super Nintendo case, but it’s not something I trust completely, having seen mixed results on other youtube channels.
If you compare these cases you can see Colcuz managed to get the case right back to the original off white colour. This other one though is decidedly yellowed. With all the keys being a quite uniform colour.
So what’s the plan here?
Well first of all I’ll strip this keyboard down and give everything a good clean. Then I think I’ll use the submersion method with keys to bring those back to a better shade, and the case I’m going to try just plonking it out in the sun for a couple of days and see what happens. It’s low risk and I think the end result I am going for with this one is just to look a bit better. It doesn’t matter too much to me if it’s still a bit off colour at the end, I’m just looking for improvement here, a bit of patina can also be a good thing.
Keen followers of my content will remember I used the submersion method on the keys from the purple and gold Amiga 500, and had problems with the keys floating. In the comments of that video I was advised by a viewer to put the keys into a plastic bag and get rid of all the air, that would mean they were all immersed and there would be no marking from the puddles on the keys.
Let’s see how that pans out shall we?
After a thorough wash and rinse
I’m ready to pour the peroxide into the bag…
Gloves are essential for this.
And a steady hand!
The plastic tub has hot water inside which I hope will help speed up the process, it’s not too hot but cold water would slow things down. All the air is now out of the bag and its double sealed.
And off it goes out into the bright sunshine, right next to the sunbathing top case.
I left the keys out there for about 6 hours, occasionally giving them a stir. And good thing too! Hydrogen peroxide is an unstable liquid, when heated it breaks down into water and oxygen. The first time I gave the bag a check I found it had blown up like a balloon! This kinda made the bag a bit of a waste of time, but I persevered and deflated the bag each time it inflated throughout the 6 hours. In the end the keys do look marvellous. Probably the best results I’ve had with retrobriting so far.
As you can see, two days in the sun has certainly taken the yellow tone down quite a few levels. It still isn’t even close to the original colour, like the other Colcuz one. But I think it’s good enough for me. If the person that wins it wants to go that extra mile they can do that too!
I will give this a treatment of 303 UV protectant (thank you Life Size Teddy Bear) which will hopefully slow down the inevitable re-yellowing.
The hard drive in here is chock full of software. I’m quite tempted to image this for my own 600. And as you can see it seems to work well.
It does take quite a long time to boot, but that might be the way the hard drive has been set up. I honestly don’t know what exactly has been installed on here at this point. But just in case there is a problem I gave the insides an inspection to make sure everything is as it should be. And at first glance I couldn’t see too much wrong.
With the naked eye there were only a few points around the caps that showed signs of leakage. Nothing was gloopy or burnt so that was a good sign. And then I looked a little closer.
Ah yes, these caps need to be changed.
Now, I must admit, at this stage I switched off the cameras, heated up the soldering iron and just got on with it. I’ve recently recapped an Amiga 600 on camera so I didn’t think it would be a good idea to do it again. It’s just a recap. What could go wrong?
Yeah, that’s what went wrong. Well one of the things.
It seems the caps were hiding a lot of problems. My usual method for removing caps is to use two soldering irons and just lift them off that way. It’s not the easiest thing to do in certain positions on an A600. These ones next to the modulator, or these 2 near the coil are very difficult to get to one side. In the past I have resorted to snipping the ones next to the coil. It’s a little lazy as removing the coil is not beyond my toolset and abilities, but so far I’ve not had an issue removing caps this way. Well. Until now. One of the pads just lifted right off the board. Oh dear I thought to myself! That’s a problem!
OK, let’s not panic. How about going back to the 2 iron method. That’s not going to let me down. Is it?
Now it’s worth mentioning that everyone has an opinion on what the best method is for removing SMD electrolytic capacitors. And everyone is right. Kinda. If you find a way that works for you that’s great. I have even tried twisting caps off, just to see what happened, and it was totally fine. But, for me, I like to use two soldering irons because in most instances I feel it’s the safest way to get the job done without too much risk. And that’s the key here. Whichever way you do this there is risk. Mechanically twisting, no matter how much you push down, is putting force across the pads in a direction where they have little strength. Healthy pads that are well attached to a board will usually be fine with this, especially if the legs have had a nice bath in electrolyte for a few decades to weaken them.
Hot air is great. Many swear by it. But you have the downside of heating not just the component pads you want to melt. And heat is heat. If those pads are damaged they have a good chance of taking the pads off this way too.
Two irons, or tweezers, to me sound like the best compromise. But they’re not perfect. You’re putting a lot of heat into a small area with double the power. It’s easy to slip and damage something else, and hard to judge if one side is melted sometimes. And it’s very easy to rush and push the cap with a bit too much force.
And this is what happened on one of the following caps. Both of these pads just lifted up with the cap. There was little I could do. The damage had already been done.
I then set about experimenting with different methods on the rest of them. Some of the caps were almost falling off the board and I managed to get these two here off just by wiggling them a bit to weaken the legs. And the horror underneath really showed what the problem was. On this side of the board the corrosion was not too bad, it hasn’t affected the pads or surrounding traces and components. I cleaned it up and installed some new caps. Not a problem.
The next area was the reset circuit. This is often an area of concern, so I took the time to remove the ceramic capacitors on either side of the electrolytic, just to be safe. In the event there wasn’t much goo under those components. But it was definitely a good idea to clean under there.
At this point I took a look at the caps adjacent to the audio jacks, which I’d already removed along with the keyboard connector for ease of access. And here, after a clean up, I spotted a problem. I decided I needed to record this and switched on my microscope to take a closer look. Right underneath C334 is a trace that has a complete break. I spent a few minutes with some magnet wire, flux and patience, and this is now a complete circuit again.
I’ve not yet had an excuse to use my new uv curable solder mask and UV light up till now. Again thank you to my super supporter Life Size Teddy Bear who bought these.
With that protected I can get these caps back on the board and then it’s time to try pad replacement. Another new skill to learn!
This area is under the caps right next to the modulator. The solder mask on these traces looks weird. What concerns me here is that the electrolytic cap juice could have worked its way under the solder mask and might be eating into the traces. I’m not sure why else it would only be flaking off on the traces and not on the surrounding areas of the solder mask that doesn’t cover copper? To be safe I am scraping all of it away. I don’t want this to be going bad a year down the line.
The trace running under this large resistor is a worry. It has corroded above and below here, and there’s plenty of corrosion on the solder too. This was in the area where the two pads lifted where the corrosion is worst. I wonder what’s underneath this resistor then? Could it have shielded the trace below? It checks out with continuity, so it’s not broken.
Oh. Well then. That answers that question! Glad I took this off now! Just cleaning the gunk away with IPA and a cotton bud reveals the trace has lost its solder mask. It still seems to be intact, so I just got here in time. I’m running a piece of braid with a small amount of solder on it to give the trace a little more mass. And then covering it up with a thick coat of solder mask. Along with all the other exposed copper. My UV lamp isn’t big enough to cure all of this area at once, so I take advantage of all the free UV outside during the day. Whilst the board is sunbathing the resistor I removed gets a bath and a scrub. And then it’s replaced. The solder doesn’t look very pretty but I tested it and it’s well attached.
I’ve been putting it off, but now it’s time to tackle the missing pads. Another thing I’m still learning about.
I’ve seen other youtubers use all kinds of methods for this job, from pieces of solder braid to bits of wire. My first instinct was to try attaching the cap directly to this nearby via and the leg of the chip below. Which would have worked just fine, but the cap to the right then doesn’t fit. So that idea was scrapped.
My next idea was to use copper tape. This is slug tape and useful for all kinds of repairs, also for discouraging slugs from eating your potted plants. The adhesive on this is not heat resistant, I know it’s possible to buy some that is, and I will try to source some of that, but for now I’m hoping this will do. I just need to get the pads in the right place
Add some flux
Drop the cap in place and solder it to the pads.
Of course it’s not actually attached to anything so now it’s in place and reasonably solid, I can add bodge wires and get it connected that way. That looks good on that side, I’m happy with that. For the other side I need to remove some of the UV solder mask I applied. It’s much harder than I expected!
And I just spotted I’d missed soldering this side of the neighbouring cap. Oops!
Shaping the bodge wire is a strangely satisfying process.
Ok, that’s all attached, how does it feel? Is it stable?
Well that seems good to me. What do you think? I might, once everything is finished and working, add a dab of hot glue to stop it moving about.
This other missing pad is a bit more straightforward. I could just solder to the top side to this scraped off area, but that would look terrible with the cap at an angle. So I’m going with another copper tape replacement pad. This time a bit wider so it reaches the connection on the right side.
Flux
And some solder.
Ah, well it really didn’t stick as well this time. But as long as I can get it flat, attached and stable I think this will still be the way to go.
I’m attaching the bottom side to hold it in place. Yup, I think that’s a decent fix. A little ugly up close but I can live with it. And it looks even better with the caps in the right alignment.
Now I just need to replace all of the other caps. Starting with these ones under the modulator.
For these I’ve switched my soldering iron tip to the witches nose one. It’s a bit better at this kind of work and easier to get into these tight spaces.
And all that’s left now are the through hole caps.
All of these were removed without damage. On the ones with heavy ground planes I preheated the area with hot air first and they desoldered perfectly.
I didn’t show it earlier but I did remove the keyboard connector and the audio jacks. I have an Amiga 1200 to recap in an upcoming episode, and I’ll show in more detail how I got these out without any damage in that video. Soldering this back in I like to move around to different points to stop heat building up too much. You can’t be too careful with plastic parts.
And lastly, after removing the remaining solder from the holes and the parts, the audio jacks are replaced.
It’s time to test.
There we go! Working great.
Just need to put it all back together, connect it back up, and test it out with all the bits inside.
To be thorough I ran through all of the tests in the Amiga test kit, including testing all the onboard and addon memory. All the sound tests. All the video tests. And the joystick and mouse tests. Everything passed with flying colours.
I better play something!
This computer, along with another Amiga 600, lots of Amiga 500’s, and many other computers (at the last count there are around 20 Commodore micros going in the auctions) will be yours to buy on October the 19th. On that day I will be hosting a 12 hour live stream where you can watch me gradually deteriorate into a tired old shell of a man trying to remember how words work. To help me through this marathon I will be joined by special guests from all around the world. This time there will be loads more than last year, with multiple people on during each slot and people coming and going throughout the day.
And all the time the auctions here in the UK and around the world will be ending and we can watch and see if we can get close to the fifteen thousand pounds the Befriending Scheme needs to buy some miniature donkeys. And it won’t just be computers and high ticket items up for sale. I have a stack of other smaller things to suit all budgets. Mugs, books, all kinds of bits and pieces I need to sort through and get ready for October. And if you would just like to make a donation to help us reach that huge and very scary target, you can do so at the just giving page which you can find in the description of this video and pinned as a comment. You’ll also soon be able to find all of the charity event details, including all the items being added to the huge list, on my own website more fun making it .co.uk
Thank you for watching and I will see you in the next one!