2 Jul
2005
2 Jul
'05
1:33 p.m.
Subject: Re: VT-131 prints?
From: Ethan Dicks <ethan.dicks at gmail.com>
Date: Sat, 02 Jul 2005 15:25:41 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On 7/2/05, Allison <ajp166 at bellatlantic.net> wrote:
All qualify. It's the board in the monitor (display) that is in
question. There is a (memory test) 100mf 50V cap and it's subject
to more than that (about 70V). It was fixed in production and
who knows how many field repairs by board replacement, I once saw
a crate of dead boards 4x4x6ft full, and that was a sample. If
the cap is replaced with suitable the failure is unlikely. I
have several VT1xx and all have been fixed over 10 years ago.
Failing boards display height and linearity problems before they fry.
Allison
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.
That sounds like once someone traces down the problem, it belongs in a
FAQ somewhere.
I haven't had any failures like that, so I guess I'd like to know
more, especially to buy a bag of 100V caps and preemptively fix some
of my terminals (I have stuff ranging from gen-u-ine VT100s, to
VT102s, a VT103, a VT105, a DECmate I, etc., and I don't recall if I
have a VT125 or VT131 or not.
-ethan