marcus@cbnewsc.ATT.COM (stephen.m.marcus) (01/14/90)
I have a Classic Mac (128k->512k->512kE->1M->2.5M) upgraded
currently with a SIMM daughter board which is showing signs
of imminent power supply failure.
The symptoms are:
(i) intermittent minor collapse of the line scan (right edge
of screen pulls in about 1/8 inch from time to time,
then goes back to normal after about 1/4 sec).
(ii) [new symptom, less frequent] intermittent "frying" appears
of video on screen. Lasts for a couple of seconds, most
noticeable on gray regions.
(iii) symptoms don't seem to be mechanically induced or removed
[thumping the video board with the back of a scewdriver in
various places neither makes it better or worse].
Does anyone have (a) a schematic of the psu/video board, and/or
(b) knowledge of what frequently fails on the board or recognize
the above symptoms?
Thanks for any help
Stephen Marcus
marcus@iexist.att.com
att!iexist!marcus