Armed with only a schematic from spies, I'll take a crack at this.
You say the +24 volts is zero. Do you really mean zero or is it
slightly (half volt to a volt) above or below zero?
Do you have zero volts on the tab of the regulator? You should if the
part is getting proper connection of pin 2 to ground.
If you REALLY have zero volts out you either have a short across the
output to ground or no input to the regulator. Does the regulator get
warm? Warm=short, cold=no current flow. R64 (the big resistor) should
be getting hot. If it isn't it may be open.
Situation 2, the output is .5 to 1 volt positive. In this case
(provided the resistor and regulator are getting hot) CR9 might be
backwards.
Situation 3, the output is negative, resistor and IC hot. This is an
overload in the HV supply.
Give me some clues and maybe I can steer you closer.
Joe Bachmann wrote:
>
> The MC1 is off of a known good board.
>
> The HV transformer rings fine..
>
> Thanks,
> Joe
>
> MKDUD@aol.com wrote:
>
> > In a message dated 3/9/2002 3:46:26 AM Eastern Standard Time,
> > joe.bachmann@newmail.net writes:
> >
> > << But, that's not it... I have replaced the regs 4 times... It's not
> > helping, the
> > diodes are good.
> >
> > I am getting 0 at the +24.
> >
> > My -24 is good.
> > My +30s are good.
> >
> > The BU is good. The 555 circuit is good.
> > The 2n3904s are good
> > MC1 and the small xformer are good
> > The MPSU07 is good.
> > The SCR is good.
> > The caps are good.
> > The HV diode is good.
> >
> > Any ideas? >>
> >
> > Have you rang out the HV trans at all? How did you test the MC1? I didn't
> > know there was a reliable way to test MC1, but if you're losing regs enough
> > to replace them 4 times, it might be "the damn red can..."
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>
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Received on Sun Mar 10 15:20:53 2002
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