> The vertical line problem is ussually blame of the analogue board, but it can
> also (sometimes) be produced by a faulty logic board or a loosy or otherwise
> problematic connection between both boards. Exchange the boards and see what
> happens. Check the two ends of the 12-pin cable tat connects both boards, and
> see if there are cold soldiers. Resolder it if neccessary. If that doesn't
> help, it's not too difficult to fix the a/b (see
> http://www.jagshouse.com/classicrepair.html - it talks about the SE/30, but I
> think the Classic's analogue board is simmilar enough for those instructions to
> fit it).
The vertical line problem in all classic compact macs is almost *always* caused by one
of just two things:
1) Bad solder joints (or bad connector pins) where the 4-pin yoke connector connects
to the analog board.
2) Bad 3.9uF/4.7uF nonpolar electrolytic cap (the tall one, usually fixed in place
with an ugly dollop of hot glue).
To fix 1), resolder (with *fresh* solder; don't just reheat) the four solder joints.
Leave the connector hooked up to prevent heat from deforming it. Then, disconnect the
connector and carefully inspect both sets of 4 pins. If any look burned, either
replace the connector, or bypass it altogether by hardwiring.
To fix 2, replace the capacitor with a low-loss ("low ESR") *nonpolar* capacitor.
These can sometimes be hard to find, or expensive (or both). I've had very good
success simply putting 4 1uF ceramic capacitors in parallel. These are cheap and
readily available.
Good luck!
--Tom
--
Prof. Thomas H. Lee
Center for Integrated Systems, CIS-205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu
650-725-3709 ph, -3383 fax
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