RE: Tech: Cinematronics Monitor

If I remember right, disconnecting the digital cable will tell the monitor
to send the beam to 0,0 which is in the far upper left (or right depending
on which way your looking at the monitor). I think the best thing to do is
have a working board hooked up to it so it tries to draw vectors on the
screen.

-----Original Message-----
From: Keith, Brendan [mailto:Brendan.Keith@wilcom.com]
Sent: Tuesday, November 03, 1998 8:07 AM
To: 'vectorlist@mcfeeley.cc.utexas.edu'
Subject: Tech: Cinematronics Monitor

Is anyone familiar with common failure modes in a Cinematronics monitor?
I have an Armor Attack (and a few other boards to test) and this recently
traded monitor will not stay active. It constantly trips the +25V breaker
in
the power supply.

I have disconnected the Keltron HV unit, so it's not that. I measure good
voltage on either side of the 7815 before the breaker trips (about 1-2
seconds).
The digital cable is disconnected so it's not trying to deflect.

I wouldn't expect the DACs or LF13331 (is that just a quad switch, like a
4066)
to draw enough current to trip the breaker. Or the op-amps.

After closing up shop last night and thinking about it some more I figured
maybe one of the deflection transistors could be shorted but the manual says
not to run the monitor with them disconnected. Is that because the
deflection
driver transistors would then try to drive the deflection yoke directly? I
have the schematics
in front of me, but I'm a little more familiar with the digital domain
rather than analog.

Is it safe to disconnect the deflection yoke alone? Then the deflection
transistor pairs?

Thanks to all, in advance.

Brendan Keith
brendan.keith@wilcom.com

P.S. Don't suggest a freakin' cap kit! Sheesh! ;)
Received on Tue Nov 3 10:01:24 1998