Re: TECH: Voltage Problems - 15V2000

From: Douglas Gauck <0k64dgau_at_gte.net>
Date: Wed Nov 13 2002 - 00:21:38 EST

Dave,

First thing I would do is to make sure it's not a G05.

Couldn't resist. Good luck.

-Douglas

on 11/12/02 11:02 PM, Commander Dave at cmdr-dave@spamcop.net wrote:

> Greetings all,
>
> Once again, I am back to working on a 15V2000 out of a BZ Cabaret. It has a
> voltage problem somewhere in the HV cage. The symptoms are that when cold,
> all is well and voltages are near nominal on all pins of the P900 connector.
>
> After about 20 minutes of warm-up, however, all the output voltage pins on
> P900 drop significantly, along with the voltage at the tube anode (example:
> 12.5 KV to 9.2 KV). The voltage on pin 8 of P900 (voltage to the HV cage)
> does not drop. The main symptom of all this is the monitor blooming (a
> little more vertical than horizontal it seems).
>
> Since all the other voltages coming from the HV cage seem to be derived from
> the HV transformer, I am thinking (hoping) that a component is "thermally
> challenged" between P900 pin 8 and the HV transformer causing all the
> voltage to drop all over (anode, P900 pin 1, 2, 4 & 5). Oh, and the freeze
> spray trick did not work this time on any of the components.
>
> I have already completed a cap kit, so ruling out those caps, I looked at
> resistor R900 (21 Ohm, 15 Watt) and noticed that the output was
> significantly lower than the input (about 60% of the input). Is this normal?
>
> I would like to hear suggestions on where to continue looking. I suppose
> that the transformer itself could be bad, but would a bad HV xformer take up
> to 20 minutes to reach a full voltage drop? I assumed that when a HV xformer
> goes bad that it just goes out completely.
>
> Thanks for any help!
> -Commander Dave
>
>
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Received on Tue Nov 12 21:29:33 2002

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