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Lisa image vertical not stable, jumping. Solution found


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Hi, I just fixed one Lisa 2/5 that had screen jumping vertically. The jumping became worse as the machine warmed up.

 

Main culprits were three electrolytic capacitors on the analog board that have leaked and corroded the surrounding areas.

These are three 16V 10uF capacitors that were purple in my case and of a unknown manufacturer. When desoldering there was a similar smell as when recapping later Macs (for instance SE/30, etc.).

I used 25V 10uF caps, and I also cleaned most of the green corrosion around them.

 

I have also replaced all the potentiometers as the original owner wanted to do this at first, but this didn't make any difference at all.

I left all the other capacitors there as they were not leaking at all and had good ESR.

 

Just my 2 cents, perhaps might come in handy to someone :)

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I had the same vertical jump issue on my Lisa 2/5 before I recapped the analog board a couple weeks ago. I too found that the small 16v 10uF capacitors had leaked, in fact one had taken out a ground trace and needed to have a jumper added. I just used some DeoxIT on the potentiometers which restored them to smooth operation.

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