21 Oct
2015
21 Oct
'15
12:52 p.m.
On Wed, Oct 21, 2015 at 3:29 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
[VT100, etc, monitor PCB]
VT101 and VT102 are the same, the 01 and 02 pertain to options that come
with the terminal. I would *assume* they have the same PSU.
--
Bill
Is that true of the vt102 as well?
I don't think I've ever worked on a VT102, but the same video monitor
boards turn up
in the VT100, VT105 and VT101 (at least). There are at least 3 different
types, at least
2 made by Ball Brothers. From what I remember the 2 Ball Brothers ones
I've seen are
very similar, the main difference being the video amplifier.
What is different between the terminals is the PSU. The VT100 and VT105
use an SMPSU
that is actually quite friendly to work on (there is a separate linear
supply to start it up,
the pscillator and control circuits are on the output side of the
isolation barrier with
transformer coupling to the base of the chopper. The VT101 has a big mains
transformer
and a linear regualtor board.
-tony