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From: t-jacobs@ced.utah.edu
Newsgroups: comp.sys.mac.hardware
Subject: Re: Apple 13" RGB Won't Turn On and Stay On
Message-ID: <1991Apr9.190649.3690@fcom.cc.utah.edu>
Date: 9 Apr 91 19:06:49 GMT
References: <1271@duteca4.UUCP> <3151@esquire.dpw.com> <1991Apr6.193738.3663@santra.uucp> <1991Apr7.172747.19637@neon.Stanford.EDU>
Sender: news@fcom.cc.utah.edu
Organization: Center for Engineering Design
Lines: 49

In article <1991Apr7.172747.19637@neon.Stanford.EDU> kaufman@neon.Stanford.EDU
(Marc T. Kaufman) writes:
>In article <1991Apr6.193738.3663@santra.uucp> jmunkki@hila.hut.fi (Juri
Munkki) writes:
>
>>First, the monitor at work would start switching off at random times, then
>>it started to refuse to power on after it swithced off. I sent it in for
>>repair and it has worked after that.
>...
>>Does anyone at Apple know what the problem could be? Both monitors arrived
>>at the same time. The manufacturing date on this one seems to be August 1987.
>
>I don't know if anyone at Apple knows, but *I* know.
>The high voltage multiplier assembly is failing.  Get it replaced.
>
>Marc Kaufman (kaufman@Neon.stanford.edu)
>

OK, here's the real answer...

There are two things than can go wrong or three if you count both of the
following as one possiblity.

The high voltage capicitor can go bad which is most likely or the high
voltage multiplier assembly as mentioned above. 

What is happening is the high voltate cap is going bad slowely and it causes
the power supply to work a little harder. It has a thermal protection circuit
that senses the overwork and shuts down the whole power supply.

The problem can sometimes be relieved for awhile by turning down the intensity
adjustment in the back (the very top hole behind the cover)

I suspect if the multiplier assembly is replaced it may fix the problem 
temporarly but the bad capicitor will come back to get you again. These high
voltage caps have a tendancy to break down after awhile.

The high voltage caps run about $80 (OUCH!) and can be replaced yourself *IF*
(YOU KNOW WHAT YOU ARE DOING) I replaced my own without incident (Electrocution
for one!) Or your Apple dealer will replace it for you for $150 or so. It
might be possilbe to get this part cheaper from Sony but I never found out the
answer to that one. I did check out all  the Mac repair places I could find in
the rags but no one carried the part. I just found an Apple dealer who would
sell me just the part.

Tony Jacobs
Center for Engineering Design
University of Utah
t-jacobs@ced.utah.edu