Re: G-05 monitors

On Aug 7, 10:34am, Christopher V. Moore wrote:
> Subject: Re: G-05 monitors
> At 05:16 PM 8/6/97 PDT, you wrote:
> >At 05:00 PM 8/6/97 -0700, you wrote:
> >>Zonn said:
> >>
> >>Yeah, that's what the +/- 25v circuit breakers were for. If the CPU card
is
> >>dead (or the monitor cable install backwards), the inputs float and as soon
> >>as they overcurrent the circuit breakers blow. This genuis of a circuit
has
> >>probably killed many a monitor...
> >>
> >>
>
> Hi All,
>
> This is my first post to this list, and hopefully not the last if I can come
> up with anything reasonable to contribute. :-)
>
> Anyway, I have a question on the above. I bought a Star Castle about a year
> ago that ended up having a dead CPU and the breakers pop, just as Zonn
> describes above. I've picked up another couple of CPU boards, one being
> a working Star Castle, and I've placed it in. I found a couple of dead
> power transistors on the heat sinks on the chassis and replaced them.
> The breakers still pop, so I put it down for a bit, and now a year later
> I want to go back and finish fixing it.
>
> My question is this:
> Is there a trouble shooting guide for this monitor anywhere?

[snip trouble shooting guide]

That's a great trouble shooting guide! A quick summary of what I look for on
these monitors: shorted/bad deflection transistors (easy to determine), bad
transistors on the monitor chassis (the ones that power the +/-15VDC,
+/-18VDC?..you can check these by trying to take a reading quickly before the
circuit breakers pop), and shorted tantelum capacitors--these DO go bad.

Good luck!

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Mark Jenison E-mail address: jenison@cig.mot.com
Cellular Infrastructure Group Motorola--Arlington Heights, IL
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Received on Thu Aug 7 08:20:17 1997