VT131 needs keyboard help

From: Tothwolf <tothwolf_at_concentric.net>
Date: Wed Jan 30 18:10:34 2002

On Wed, 30 Jan 2002, Tony Duell wrote:

> > I can vouch for that. My VT340's flyback let out its magic smoke about 6-8
> > months ago. Does anyone happen to have the service manual and or a
> > replacement flyback for this thing? I'd like to repair it in the near
> > future. What most often causes the flyback to go out? It worked fine one
> > day, the next it let out a cloud of smoke.
>
> My experience with the VT330 and VT340 suggests that there's no other
> component that fails to kill the flyback. It's just that the HV
> winding in the flyback breaks down. The flyback case cracks, lots of
> smoke comes out...

This seems to match up with the behavior the terminal exhibited. I heard a
few 'plink' type sounds a few times, accompanied by 1/2 sec or shorter HV
drops. I'm guessing the flyback was starting to arc internally? This
terminal had done this off and on for a considerable amount of time...at
least a year. The flyback's case didn't crack on this one (that I noticed
anyway). I pulled it out of service the second it quit working, so that
could have something to do with it. I opened it up, and found a
considerable amount of smoke had escaped from underneath the flyback,
which would have explained the cloud and smell that prompted me to yank
the cord from the wall.

> You should check the horizontal output transistor (on a heatsink near
> the flyback) and all the diodes and capacitors round the flyback. But
> most likely they're fine.

Will do. Do you have any suggestions on a replacement flyback here in the
US? I'd also like to find a service manual for this terminal, so that I
can go through the basic checks and alignment procedures once I find a
replacement.

-Toth
Received on Wed Jan 30 2002 - 18:10:34 GMT