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In_focus

Posted Sun Dec 09, 2018 2:49 pm

Hi all, new to this forum and first attempt at repairing an Amiga. I actually have two, an A500 and A500 Plus. The Plus has some signs of life so I'm going to concentrate on this one first.

The machines were stored many years ago after the kids moved on to Windows based PC's around 1995. They were rediscovered in the loft (attic in the U.S.?) while bringing down the Xmas decorations and my daughter thought it might be a good idea to introduce my 4 year old grandson to the Amiga.

The Plus was working when put away but at that time I was unaware of the damage the Ni-Cad battery could cause and indeed the corrosion looks pretty bad. It has been removed, the PCB cleaned with copious amounts of Isopropyl alcohol and there is some swelling under where it was positioned but the traces on the top layer seem intact, leakage goes right around the edge of the PCB all the way up to the video stage but it does boot and the FDD is clicking but does not seem to detect a disc is inserted. There is monochrome video at the RCA connector but the amplitude seems pretty low, the TV it's connected to often doesn't recognise that sync is present and doesn't unmute the blue screen. It's even worse with the A501 modulator but there is colour, unable to tell if the audio department is OK.

Any tips would be welcome.

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intric8
Seattle, WA, USA

Posted Sun Dec 09, 2018 3:11 pm

Whew, that sounds pretty rough. RogerWilco486 recently posted about some similar surgery he had to perform for his A3000.

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Dynamic_Computing

Posted Mon Dec 10, 2018 7:11 am

Can you post some pictures of the damage and damaged area? (They need to be less than a MB, so you may have to edit your pictures if you take them from your phone) - That will help isolate what components may have been damaged. Just the fact you are getting some response from the old girl is good news, though!

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In_focus

Posted Wed Dec 12, 2018 11:00 am

Some pics of what seems to be pretty severe damage but I've made some excellent progress today.
5 (2).jpg
3 (2).jpg
4 (2).jpg
More cleaning and some attention with a fibre pencil on the corrosion have helped.

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In_focus

Posted Wed Dec 12, 2018 11:15 am

7 (2).jpg
I now have a healthy looking video output and syncs so I now turned my attention to the FDD
6 (2).jpg
Using an Ohm meter the write protect switch was producing a 0 Ohm reading but not the disc detect switch on the right, a careful dribble of switch cleaner solved that one but unfortunately my Workbench disk appears to be corrupt.
9 (2).jpg
Digging out an old game produced this with wonderful stereo audio, I have to say I'm delighted with the outcome so far. I'm unable to find the old RGB cable and have been looking for a 23 way D sub to make a replacement but they now seem to be unobtainium over here.





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