Subject: VT-131 prints?
From: Dennis Boone <drb at msu.edu>
Date: Sat, 02 Jul 2005 00:57:43 -0400
To: cctech at
classiccmp.org
I have a VT-131 suffering from video circuit problems. The logic
seems to be ok -- does a self test, led dance, emits a normal beep,
and ends with the on-line led lit. The crt filament is glowing.
Key click happens when keys are pressed. No screen display.
I've turned up brightness in set-up, flying blind. Haven't twiddled
the pot yet. So far, I've just taken the lid off, and am looking
into the still-assembled chassis.
The video board has some very charred-looking spots around the solder
pads of one component (cap? spherical white ceramic-like device with
two stout leads) down and to the right of the brightness adjustment.
The tech manuals from bitsavers and
vt100.net don't give me enough
info to identify the component in question.
Anyone have prints they'd be willing to scan bits of for me? Or read
off to me by e-mail? Or have "replace this, kid" or "you're
screwed"
specific knowledge of this scenario?
TIA,
De
Common VT1xx part failure. Seemed they made the video board with a
50V cap where a 100V cap should be. Huge numbers of them were made
and failed but amazingly there are still many in use that havent.. Yet.
It is repairable as it cooks a cap, diode and resistor.
The Video board is common to most VT1xx. Mine are deeply burried.
Allison