WG Deflection meltdown

I was just working on a WG Color XY that I have fixed a few times in the
past. It belongs in a tempest that belongs to a group at work and gets left
on pretty much all the time.

Last time I worked on it I put in a full set of new 2n3716's and 2n3792's
and installed a LV2000.

I get a call a week ago that it has died again.

I check it out and the monitor ate the low voltage pair and the Y deflection
pair all 4. Thought it a little odd but replaced them. As I was getting
ready to reinstall the the deflection board I noticed some burn I hadn't
seen before.

Looks like R711 and R703 wanted to reenact the end of WW2 for the Japanese.
Total meltdown and cratered. In the process they burnt through C703. Also
looks like R702 went toastie at the same time (just black and burned not
exploded).

The two power fuses are fine Fuse 700 is blown.

So the question is what in the blazes happened. Any ideas?

Second question and I am just posing this for discussion, could the LV2000
have given the board enough rope to hang itself with? Knowing that it is
designed to handle the loads better could that be a problem? I am leaving
that up for discussion by the better on this list.

A final question: what are the yoke resistance's supposed to be? I have
seen one case before where a yoke winding shorted the X & Y sides together
completely gutting the Y side (didn't hurt X at all). And I want to check
it out before I put another deflection board in this monitor.

Thanks,
David
Received on Sun Jun 13 01:48:45 1999