macintosh plus video issue that i think i definitely know the cause of

[bedroom]

hi all,
i've got a mac plus that i've been using for some time now. i pretty much use it daily. as such, i assume that the intermittent drop of the video signal is from the solder joints on the board cracking or loosening over time. i dont hear any sort of strange whirring coming from the transformer, but i do hear a strange sort of ticking. i know the board is due for a recap and i've just put off long enough. when i tap the side of the plus the signal comes back, so i'm pretty confident it's just the joints, but if anyone has any other suspicions, please let me know.

 

[S. Pupp]

My Plus developed the same symptoms after I think six years of daily use (1992). It saw another three years of daily use, getting slapped on the side from time to time to bring back the video, before entering semi-retirement.

At age 27, the Plus underwent treatment with desoldering/resoldering of the flyback, and was cured of this particular ailment.

Ticking can come from the floppy drive. It comes from mine, which (after replacement of the cheese gear) still works OK.

 

[Mu0n]

Almost certainly a cold solder joint crack on the underside one of the J connectors that brings power or the circular joints where the flyback is. Inspect carefully under magnification and see the crack, and the best way is to remove most of the old solder of a joint before putting in fresh one, rinse and repeat for these other big joints.

Proceed methodically; do this rejuvenation work for joints first. Then test. Then think about caps at a later time.

 

[Paolo B]

Caps are unlikely the issue. I have also bad experience with cold solder joint cracks: hard to catch by naked eye, but they are there.