21 Oct
2015
21 Oct
'15
12:29 p.m.
[VT100, etc, monitor PCB]
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