Reliability of Sun 3/50's

[Karl Kleinpaste]

karl at triceratops.cis.ohio-state.edu (Karl Kleinpaste) writes:
   >In just the last couple of months, we have had rather a lot of the flyback
   >transformers in our 3/50 monitors going bad.

aad at stpstn.UUCP (Anthony A. Datri) writes:
   I've had more problems with monitors (2/50, 2/120, 3/50) than any other
   piece of hardware.  What are the symptoms of the flyback transformer going
   bad?

A dead screen and a high-pitched whine.  I received some extremely useful
mail yesterday from Lewis Jansen <lrj at helios.tn.cornell.edu>, detailing
what his group has learned about dealing with this problem.  The short
version is that there's a high voltage line (24kv) going to the CRT; it
presses against the left side grounding shield.  After being heated in the
monitor a long time, the insulation decays followed by arcing.  The final
eventuality is shorting completely through, ruining the flyback.  He says
they've taken to taping some folded `fish paper' onto the ground shield,
which insulates and also holds the wire out a bit from the shield.

Be CAREFUL around those high voltages, folks...

Many thanx to lrj for the pointer.

--Karl