Re: Cinematronics monitor help

From: Matt Rossiter <rossiter_at_ni.net>
Date: Mon Feb 25 2002 - 13:05:44 EST

I think the breakers will trip if the LF13331 analog switch is bad. I fixed an
early space wars monitor that had that problem.

You might want to try swapping the analog switch from the a working monitor. Be

really carefull though - they are hard to find.

You should also look at these service notes if you have an older monitor.

http://www.spies.com/arcade/schematics/cine/serv3.tiff
http://www.spies.com/arcade/schematics/cine/serv18.tiff

Matt

Mark Jenison wrote:

> > It sounds like you are only getting chatter in one channel, and that the
> other
> > channel is pegging the yoke to one side, causing the circuit breaker to
> blow.
>
> Is it possible to run the monitor with just ONE yoke winding connected (just
> x or just y)? That way I could narrow down which circuit is failing.
>
> > Check the power transistors, using the standard diode setting on a VOM,
> and see
> > if any are shorted.
>
> Hmm...I replaced the transistors and they still test fine, unless one is
> failing under load. Maybe one of the DACs are bad...
>
> > >BTW, the Cine monitor doc on spies says to unplug the harnesses to the
> heat
> > >sinks and leave the yoke plugged in to get "a smaller picture". I tried
> > >this once before I got this far and it burned up a bunch of resistors.
> >
> > That is a really bad thing to do. Unplugging the heatsinks causes the full
> load
> > of the yoke to be handled by a couple of small pre-driver transistors
> through a
> > couple of 47ohm resistors (which is probably what you smoked before). Who
> ever
> > recommended this must have inhaled too much of that resistor smoke.
> >
> > Now if there were some test software that generated a very small picture
> in the
> > middle of the screen, small enough as to not overload the small pre-driver
> > transistors and resistors, this could possibly be a valid test.
> >
> > I'd have to look into the pre-driver current loads, to verify that a box
> small
> > enough to keep from overloading the pre-drivers, and yet large enough to
> be
> > useful, could be drawn.
> >
> > If anybody is interested in such a program, I'm sure I could have it
> written by
> > the end of the week. (Given my current schedule.)
>
> I'm for anything that helps debug these monitors.
>
> --
> Mark Jenison
>
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Received on Mon Feb 25 10:07:31 2002

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