Mac Plus and Mac SE/30 video issues

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Last seen: 1 year 10 months ago
Joined: Dec 28 2019 - 15:13
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Mac Plus and Mac SE/30 video issues

I have a couple of old Macs that I'm working on - a Mac Plus and a Mac SE/30.

The Mac Plus started with a bong, but had no display.  The SE/30 displays alternating black and white horizontal lines.

I tore both down and did a basic cleaning, hit the jumpers / headers with contact cleaner and reseated socketed chips.  There was no change in the SE/30, but the Mac Plus now has a display, albeit with multiple broken vertical lines.

I still have a lot to do.  I plan on reflowing solder joints on the headers and recapping the analog and motherboards.  Given that the SE/30 has those nasty little failure-prone surface-mount can capacitors, I suspect it's issue lies there (I see no evidence of leaking caps on it yet, though).

In any case, I just thought I'd post here to see if there's anyone who knows if these problems are  attributable to something more specific, like a bad memory chip, rather than more general issues like solder joints and/or failed caps.



Last seen: 16 min 43 sec ago
Joined: Feb 27 2021 - 18:59
Posts: 451
 Mac SE/30 with alternating

 Mac SE/30 with alternating black and white horizontal lines


This is textbook Simasimac (also see here). It is usually caused by the surface mount electrolytics leaking (as you suspected). The leakage is between the components and the PCB, so it is not necessarily visible prior to rework.

The solution is capacitor replacement and thorough board cleaning, preferably ultrasonic.

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