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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Topher on October 27, 2016, 09:56:25 AM
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Hi All,
I am going to attempt an A500 Plus repair (The dreaded Battery Leak)
Attached is a photo of the issue - Question is has anyone attempted this and if so how difficult does this repair job look ?
If anyone has the time to look and advise then thank you in advance :)
It seems C12 will need to be replaced but cannot find it anywhere is there an alternative i can use ?
U12 + U13 replacements have been ordered.
http://imgur.com/j2L7lyd
Thanks
Chris.
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I repaired one in a much worse situation.
The corrosion was almost everywhere, even near the psu plug.
Except the ROM, everything else was cleaned and resoldered and some bypassing cables.
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C12 is the same rating as C10 and C11 over to the left. Its just a simple capacitor. You can use any thats rated the same as it is. It doesnt have to look like that one. As for the rest of the repairs dont try to repair the traces, they are much to hard to fix on the board. Just get some very thin solid copper wire wrap wire and use it to jumper between the bad spots.
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Thanks for the information guys:)
Would you say individual wires from an ethernet cable be suitable for the bypass wiring ?
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Thanks for the information guys:)
Would you say individual wires from an ethernet cable be suitable for the bypass wiring ?
Yeah that will work as long as your using a single strand and not multiple strands. Also you will want to use something like conformal coating or epoxy to cover it up. You don't want bare wires touching other things. I prefer to use wire wrap wire since its very thing and covered with insolation.
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Yeah that will work as long as your using a single strand and not multiple strands. Also you will want to use something like conformal coating or epoxy to cover it up. You don't want bare wires touching other things. I prefer to use wire wrap wire since its very thing and covered with insolation.
Is there some good reason why not to use multiple strand wire as bypassing defective traces?
I repaired many Amigas with old pc power led/reset or equivalent cables with no problem. And these are very small gauge wires with multiple strands.
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Try wire wrap wire. Very thin, insulated and not too hard to work with. I've redone several traces with it.
And you can even find it at Radio Shack!
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A single strand keeps its form better and less danger of stray hairs to make a short.
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That doesn't look too bad at all, just scrub it with vinegar to neutralize the battery electrolyte and then rinse with alcohol or distilled water and dry thoroughly. Those capacitors are just bypass caps on the power rails to the ICs, they are probably 0.1uF (100n), anything you can find that looks similar will have a high enough voltage rating. You probably don't even need to replace it, in most cases equipment will still work with one or two of those missing depending on where they are in the circuit. Even the IC's may well be fine once you clean off the corrosion, I had one that had way more blue corrosion than that on the pins and it still tested fine after I cleaned it.
I highly recommend kynar insulated wire wrap wire for fixing damaged traces. You can form it neatly and use dabs of hot glue to hold it down when you're finished. It's what they used for fixing PCB errors in the factory back in in the days before CAD mostly eliminated them.
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What do you guys think of the traces under where the battery was positioned thats what was bothering me most as they have discoloured. Does it mean that those traces are destroyed ?
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Not necessarily. You should scrub the solder mask off the discolored traces and scrub or scrape off the corrosion until you get clean copper. If the trace is not broken then it's probably ok but you should verify with a multimeter. The most vulnerable area are vias, these are tiny plated through holes used to pass the signal from one side of the board to the other. Electrolyte gets into those and rots out the plating leaving an open circuit. You'll want to remove any affected ICs to clean and inspect underneath them too. Be careful because the corrosion affects the solder and seems to raise the melting point. Unless you have a vacuum desoldering tool you might consider cutting the legs off the ICs and remove the pins one at a time, but only do this on cheap commodity chips that are easily replaced. It's easy to tear up the board and turn a small job into a big job.
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Thanks for the tip, got one roll of Kynar wire off eebay... ;) Definitely will make neater repairs.
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Thanks for the tip, got one roll of Kynar wire off eebay... ;) Definitely will make neater repairs.
Perfect choice!
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You'll need a stripper that can handle the Kynar wire too, most regular wire strippers don't go small enough.
I forgot to mention another useful trick for getting the contaminated solder out of holes is to add some fresh solder to the joint first. Sometimes you may have to do this several times but eventually you can usually suck out the old stuff. Use a properly set temperature controlled iron to reduce the risk of lifting pads. If the through hole plating gets damaged you will have to solder the IC pins on both sides of the board so check carefully.
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Yes, good point about wire stripper. Maybe should get job done with razor blade knife if wire stripper won't do.
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Thanks for your suggestions guys :)
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Hi guys,
I have decided when doing this repair to recap the board - can you please tell me what the recommended CAPS are ? if so can you provide links ?
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I suggest doing one thing at a time, unless the machine is dead and won't boot already. Fix the battery damage and get that cleaned up, verify it works and then do the re-cap. Others will have to suggest the cap types as I've never done it on an Amiga but I use SMD tantalum or ceramic chip capacitors to replace SMD electrolytic caps on other stuff.
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As James said, try to do one repair at a time. Reduces the chance of introducing more problems. The A500 and 2000 don't have the same capacitor problems that the later models with the surface mount caps that leak and corrode the board.
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Ok willdo thanks guys
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Sorry for the lack of updates.[FONT="]
So I finally got the time to finish the repair today ended up having to change one chip the DM74L5244N to the left of the battery. I used wet/dry sandpaper to check the traces (which were fine) and recovered them with clear nail varnish.
http://imgur.com/T1mIx0B
Thank you to all that offered advice and help :)
[/FONT]
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So does it work?
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Glad you've made it :-)
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Sorry for the lack of updates.[FONT="]
So I finally got the time to finish the repair today ended up having to change one chip the DM74L5244N to the left of the battery. I used wet/dry sandpaper to check the traces (which were fine) and recovered them with clear nail varnish.
http://imgur.com/T1mIx0B
Thank you to all that offered advice and help :)
[/FONT]
Soo swweeet to see one 500+ with us again! Good job dude. My first Amiga was 500+, so still have soft spot for these ol' clunkers.
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So does it work?
It does indeed :)