Monitor Repair Help Needed

From: Wayne M. Smith <wmsmith_at_earthlink.net>
Date: Sun Jun 24 20:06:56 2001

> Hmmm... I have a major objection to 'whacking'
anything near a CRT....
> Not only the risk of CRT inmplosion, but even if you
don't crack the CRT
> you can certainly knock the electrodes out of
alignment.
>

This was the one that was going in the trash bin. In
any event, the mounting screws were well back and below
the CRT. This thing sits in a heavy steel frame that
is a field replaceable.
>
> In general, if something isn't working properly, the
last thing to do is
> tweak the adjustments. My guess is that this did once
have enough
> height, and the reason the height has decreased is
due to component failure.
>
I didn't know it wasn't working properly until I turned
the vertical all the way up given that I thought the
problem could be rooted in the fact that I was moving
the tube from one type of system to another.

> Look for dried-up electrolytic capacitors round the
vertical deflection
> circuit. If it uses the well-known TDA1170 chip, then
there are a couple
> of capacitors hooked up to that chip that can cause
this problem.
>
I have saved the old unit. Perhaps the boards can be
swapped. (I know, you're against swapping, but that's
all some of us cavemen are capable of.)

> Be careful cutting the stuff off near the yoke (or
other wirewound
> components) -- it's easy to damage the insulation. I
normally cut it away
> roughly in the centre of the blob (to free the yoke),
then remove the
> yoke completely, then peel off the remains of the
gunge from the yoke and
> the CRT flare. On the other hand, you shouldn't need
to reposition the
> yoke. this monitor worked once, with the yoke in that
position. The yoke
> hasn't moved, so the fault must be due to other
failures.
>
Thanks for the advice.

-W
Received on Sun Jun 24 2001 - 20:06:56 BST