From: kelleyb@austin.ibm.com (Kelley Boylan)
Subject: Re: Screen Death: Mac Plus/512
Originator: kelleyb@kelleyb.austin.ibm.com
Reply-To: kelleyb@austin.ibm.com
Organization: IBM Austin, PowerPC
Lines: 29


> I have a (very old) Mac 512k and a Mac Plus, both of which 
> have the same problem.
> Their screens blank out, sometimes after a minor physical jolt
> (such as inserting a floppy in the internal drive), sometimes 
> all by themselves (computer left to itself just goes blank).
> 
> I have replaced the wires connecting the logic boards and the 
> video board, because it seemed at first that jiggling the wires
> made the screen come back on.  This worked for a while, but the
> blanking out has returned.
> 
> Can I do anything?  Do I need a new power supply?  A new CRT?
> A new computer?

I had the same problem with my 512 a long time ago.  Resoldering
the joints on the motherboard (all of them) fixed it.  Turns out
that continuous heating and cooling caused annular (ring-shaped)
cracks to develop in the solder, effectively cutting the video
circuitry off.  If you're not a solder-jockey you might want to
have someone else do it -- I took mine to an electrical engineer
buddy -- but it was a 20-minute job, tops.

-Kelley-
-- 
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Thomas Kelley Boylan, PowerPC, IBM Austin, kelleyb@austin.ibm.com
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                  I buy and pay for my own opinions
