The problem is, both the common diode and cap that fail, did, and now it
won't power the CRT on. The keyboard lights come on and I can go into setup
mode but there is no display. I will try the BNC output though.
-----Original Message-----
From: cctalk-bounces at
classiccmp.org
[mailto:cctalk-bounces at
classiccmp.org] On Behalf Of Tony Duell
Sent: Friday, February 09, 2007 6:33 PM
To: cctalk at
classiccmp.org
Subject: Re: Need an Elston analog video board for VT100
Yeah, I've already tried that. It didn't fix the problem.
Also, it
should be noted that Radio Shack's parts area
has shrunk to
something
useless in most cases.
Got any other suggestions? I have no idea what it could be. I've
replaced the flyback/choke, the PSU, and repaired the
analog board.
Only things left are the logic board and the CRT.
Maybe I
should pull
the analog board and resolder it? I've got no
clue.
You've not even told us what the problem is!.
Now what _I_ would do is grab the printset (I assume the
VT100 printset is on the web somewhere...) and start by
checking the PSU outputs. Are they all correct?
Then connect a standard RS170 (TV rate) monitor to the video
output BNC socket. Doe you get video there? Does the terminal
seem to work on the external monitor. If so, then the logic
board is probably working fine.
Now go back to the internal video syustem. Use an EHT probe
to check the EHT on the CRT anode connector (should be around
12kV I think). Is the CRT heater glowing? Check the CRT gun
electrode voltages. Do they seem sane?
-tony