RE: Wierd Tempest problem (power related?)

My guess would be that you have a short in the monitor connector or the neck
board of the CRT that is grounding one of the red, green, or blue color
signals. Because these are TTL signals, shorting one of them could short
the whole +5VDC power rail, which would keep the board for powering up. To
test this, with the PCB plugged into the monitor, with everything turned
OFF, use an ohm meter to test for continuity between +5VDC and ground. If
you have a short, then remove then unplug the PCB from the monitor and start
probing for the short.

Joel-

> -----Original Message-----
> From: Patrick Lawrence [mailto:pjl@patsoffice.com]
> Sent: Thursday, January 11, 2001 3:09 PM
> To: vectorlist@synthcom.com
> Subject: VECTOR: Wierd Tempest problem (power related?)
>
>
> Hello All,
>
> I'm having a wierd problem with a Tempest. If the power is
> supplied to
> the monitor the game does not appear to work (no sound, no
> P1-P2 lights,
> test switch does not take it into test mode.) If I
> disconnect power from
> the monitor, then the game is playable blind.
>
> I've swapped out the AR-II and the power transformer assembly and the
> problem remains. Voltage to the monitor looks good and voltage to the
> game board looks good when the monitor is powered.
>
> Any ideas?
>
> Thanks,
>
> Pat
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Received on Thu Jan 11 17:00:25 2001