So I am pretty fed up trying to fix these analog boards for a Compact Macintosh Plus. I either get to a solid horizontal bar or chirping. None of the repairs I have done have changed anything. Out of all the vintage machines I have worked on the Compact Mac's are the worst/least forgiving. IF there is anyone out there who is more familiar with these wretched systems I would be willing to trade two 630-0102 Boards for a working board of the same style. Please PM me.And in case someone was curious, I have 3 logic boards that are all functional when used with my working analog board so I know the Logic board isnt culprit.Thanks,Frustratingly hopeful,Mick
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The Plus and older analog boards are notorious for the big solder joints failing. Often they can be fixed by just re-flowing those. However they were also under built for the power requirements of those machines, especially if you have any add-ons so they often needed rebuilt, even back in the day. The problems were also exascerbated by the lack of a cooling fan in those machines which led them to run a lot hotter than they really should have. A cooling fan usually made them a lot more reliable. Anyway, I haven't messed with one of those early Macs in 20 years and I got rid of anything I had older than a Mac II quite a while ago, so I don't think I can probably help you.
I have checked all the solder joints and reflowed a bunch just to be precautionary. I even tried swapping the flyback with a known good to no effect either.
This might be of interest:
I knew that there was one particular capacitor that often blew, this says C1. If my memory serves, the other one that often went was C8. Most often the big electrolytic caps are easy to spot if they are bad, they will be bulged out and sometimes show signs of leakage. But not absolutely always. So that would be something I'd look at swapping out. Those caps are not expensive or hard to get. If you've got a Fry's nearby they probabably have them, if not you can order them online.
I have pretty much replaced all the caps and IC's and still no go.. Im pretty frustrated with them. No other boards give me this grief. Working on apple II boards is a breeze by comparison.
Next I would try replacing the transistors and the diodes. I might meter all of the resistors to see if they look reasonably in spec.
I have replaced every transistor and IC as well. Like I mentioned I am DONE with these boards. I cannot give them anymore of my time. I know alot of readers might suspect I am a novice; its not the case.. These compact MACS are a nightmare to work on compared to anything else. I am currently repairing a bunch of really old, and weather ( i mean real weather, as in left to the elements) beaten apple II monitors model A2m2010 .. I am having very little trouble fixing those and replacing components... Just the compact MAC analogue board is my bane it would seem.
I really wasnt looking for any troubleshooting help in this case as I literally just wanted to trade and swap boards. Someone messaged me and will trade a working analogue board for two of my bad ones so Thank you everybody, seems I am all set.