[comp.sys.dec] VR260 Plague

joltes@husc9.harvard.edu (Richard Joltes) (11/01/90)

Does anyone have any hard data on a fix for the infamous VR260 plague (other
than buying a better monitor, that is)?  For anyone not familiar these tubes
have a tendency to blow out deflection boards at irregular intervals -- you
know you have one when the monitor won't fire and all you get is a noise pulse
from the rear and a slowly blinking power LED.

I had heard that the culprit was the IRF622 N-style regulator on the board.  I
tried replacing one, though, with no effect, but I'm REALLY TIRED of having to
call DEC in to replace the boards.

Anyone know of a good fix?

Thanks,

Dick Joltes					joltes@husc9.harvard.edu
Mgr. of Hardware & Facilities
Harvard University Science Center

jcd@pitt.UUCP (Jim Durham) (11/10/90)

In article <4563@husc6.harvard.edu> joltes@husc9.harvard.edu (Richard Joltes) writes:
>Does anyone have any hard data on a fix for the infamous VR260 plague (other
>than buying a better monitor, that is)?  For anyone not familiar these tubes
>have a tendency to blow out deflection boards at irregular intervals -- you
(stuff deleted)>
>I had heard that the culprit was the IRF622 N-style regulator on the board.  I
>tried replacing one, though, with no effect, but I'm REALLY TIRED of having to
>call DEC in to replace the boards.
>
The culprit seems to be the flyback transformer.

>Anyone know of a good fix?

Apparently DEC has a new version of the board. I thought this fixed the
problem, but from what you say, maybe not.

I was wondering if a fan would help. VR-260s seem to run really warm.
If you notice, the source resistors for the Mosfets burn the board
and there's a lot of heat coming out the vents. This would cool the
flyback and the Mosfets.>

-Good Luck
Jim Durham   (jcd@cs.pitt.edu | durham@w2xo.pgh.pa.us )