21 Feb
2003
21 Feb
'03
7:44 a.m.
Look at the flyback transformer. That is the ceramic
thing with the thick
wire attaching to the CRT tube. Does it have a crack around it with
hardened "ooze" coming out of it?
Will look when I get home. I don't remember there being a wire that went
from the PS board to the tube, other than ground straps
from the cage
assembly. There is a ceramic transformer-looking thing and the wires
on it
are rusty, which is one of my second-order questions (how to get rid of the
rust and arrest the corrosion process).
90% of the time the vt320's fail, it is this
transformer shorting out, which
takes the horozontal transistor(?) with it. It heats up, cracking open, and
spewing out it's magic ooze. If this is the case, you can replace both of
these parts, and it will work again. DEC used some really crappy flyback
transformers in these things.
Is that transistor on the PS board as well? If so, why does the PS board
appear to work "unloaded"?
If that's the fault, are the scorch marks under the blue resistors normally
there, or unrelated?
However, it would probably be cheaper just to replace
the whole terminal
in that case. The transformer will probably cost at least $30.00, and the
transistor around $5.00. Then comes the fun part of trying to extract
and replace them without destroying the circuit board.
Sigh. I may look on it as a learning experience, if I can find a
replacement transformer that fits.
- Mark