22 Feb
2003
22 Feb
'03
7:34 a.m.
Mark Tapley wrote:
Will check the flyback xformer, and rip it off the
board (OK, I'll desolder
it...) if it looks guilty. Probably will take the HOT, if I can identify it
unambiguously, as well. Then it's back to the parts-shopping game. Sigh.
It's probably normal. If you want intresting burn marks, look at the
LA210, which would discolor a large area of the case above the power
supply. Customers always asked me if that was normal. I think a lot
of the DEC terminal/printer stuff left scortch marks somewhere.
>If that's the fault, are the scorch marks
under the blue resistors normally
>there, or unrelated?
>
>
Still curious about this. The scorch marks make me nervous - can or should
I try to heat-sink at least the resistor with the bad scorches around it?
Also, what if anything should I do about the rusting
smaller transformer on
the PS board?
Sounds like someone spilled something liquid into the terminal at some
point. Heat + liquid + wire = Instant Rust.
If you just want to use the terminal, I wouldn't bother. More likely to
break something than any cleanup would fix. If you want something
for people to look at, then you might be concerned. I'd only be bothered
about it if it was too excessive, then I'd try scraping off the excess
with a knife, or probably just swap in another power supply from a
"dead" one (which I usually had a couple of).
After the flyback, I had problems with badly scratched picture tubes,
and dead tubes. I still don't know how they could scratch them up so
badly.
If it were a vt420, after the flyback (probably from the same compny)
I'd look at one of the cables going from the CRT to the main board.
The contacts would heat up, and either burn the connector out, or weld it
to the motherboard.