ostroff@oswego.UUCP (Boyd Ostroff ) (10/31/86)
Keywords:sick mac, upgrade, video, power supply
(Note: this is a re-posting of my previous article which never made it out)
We have a one-year-old 512K Mac which was upgraded last winter to a Mac Plus
(800K drive, SCSI port, 1 meg. memory). Two days ago it started having
video problems. 15 minutes after booting a black vertical line appeared
on the left side of the screen. Then the contrast became too great -
the light grey desktop turned almost black. While using Excel, for
example, "highlighted" areas of the spreadsheet became _totally_ black
(the text wasn't visible at all).
Dark lines or text on white backgrounds "smeared" and the individual
pixels actually twinkled. I don't think it's a memory or software
problem, since screen dumps (caps lock-command-shift-4) print
properly even though the display is loused up.
This same behavior repeated itself the next time the system booted.
In both cases, however, after a couple of hours of power-on, everything
was fine. Yesterday the same problems showed up immediately at boot
and within 5 minutes the screen totally blacked out. After about 40
minutes the screen flickered on and off and then came back up, as
if nothing had ever hapenned!
Today it has been on for 8 hours continuously and has worked perfectly
all day...
Does this sound familiar to anybody? I've read a lot about power
supply problems with upgraded (1 meg) Fat Macs, but in our case
it seems that the video display is all that is being affected - nothing
was lost in memory and command key sequences still work even when the
screen blacks out.
Any suggestions before we take it back to the dealer (its not under
warranty)? It's an intermittent problem and we're afraid it won't
show up on the dealer's service bench...
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US Mail: Boyd Ostroff, Technical Director, Theatre Dept.
SUNY Oswego, Oswego, NY 13126 (315) 341-2138
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