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Home Forums Macintosh Plus Issues — #9 Macintosh Plus Issues — #9
Post #9 by techknight
Source ForumMacintosh Plus Issues — #9
CategoryHardware
Post DateWed, 22 Jan 2014 - 05:08
Original URLhttps://68kmla.org/bb/threads/macintosh-plus-issues.29716/
Post
Nah, I'd definitely like to get this thing up and running. If I can get past the CRT and get the analog board out, then I can probably dive into fixing it. My dad can solder better than I can, I could leave the job to him, but until I can get it apart I have no way knowing if it's cracked solder joints, bad capacitors or both. Could be both, the capacitors aren't surface mount on the analog board right?
For soldering the only thing you have to do is get it open. All the soldering points are easy to get to without removing anything besides cover sheets. You won't even have to disconnect anything!

As for caps, I don't think they are the issue, but yes one should not rule then out yet. Only because the booting is too random. Usually a component failure causes a more consistent issue. Also it seemed like once it warmed up a bit, it ran. Caps get funky once they warm up, not when cold so much. However cracked solder joints do work better when warmed up from thermal expansion.

I really would not have that thing plugged in until you get a closer look.
Not quite. Caps get better as they warm up. Not the other way around. As the dried electrolyte in the capacitor gets warm, the ESR drops and capacitance rises, improving circuit operation.

To perform an experiment, grab a capacitor meter and get a weak/bad capacitor. measure it cold. Then heat the crap out of it, and watch the measurements. they go up. It eventually plateaus and goes down, but thats beside the point and usually happens when it it reaches outside its operating temperature

mp.ls