Re: Tech: WG6100 Help:(

I think I and Rodger agree, so start checking connections around Q101 / Q103
(check for broken contacts, solder joints, screws on Q103) and in doubt ,
replace them. If you have a digital multimeter which can check a diodes forward
drop, check that the E-B and C-B voltage drop on Q101 and Q103 are about 0.4 -
0.7 V.

Rodger Boots wrote:
>
> Either Q101 is open (emitter to base) OR Q103 on the chassis is open, OR Q103
> isn't a 2N3792 OR there is a bad connection at J100. You should have
> approximately -27.7 at Q103 emitter (J100 pin 5), -28.4 at Q103 base (J100 pin
> 6), and -33.3 at Q103 collector (case) (J100 pin 7). If the emitter and base
> are within a volt of each other the transistor is probably OK and Q101 (or the
> connector) is the problem. If you have more than a volt difference between the
> emitter and base of Q103 then it is either bad or the wrong part. If you don't
> have at least -28 volts or so at Q103 case (collector) the transistor may have a
> loose mounting screw, an insulator on the screws, or J100 problems at pin 7. If
> ANY of that happened Q101 would probably instantly blow.
>
> Justin Monast wrote:
>
> > Hey Tek,
> > I have checked the voltage at D105, so before the voltage passes through its
> > at -27.7 and on the other end its at +11, I hope that makes sense..
> >
> > -----Original Message-----
> > From: owner-vectorlist@synthcom.com
> > [mailto:owner-vectorlist@synthcom.com]On Behalf Of Tek
> > Sent: Saturday, May 20, 2000 11:45 AM
> > To: vectorlist@synthcom.com
> > Subject: Re: VECTOR: Tech: WG6100 Help:(
> >
> > Justin Monast wrote:
> > >
> > > Hey Guys,
> > >
> > > I have a quick question, on my defection board I'm getting the correct
> > > reading on the low voltage power supply +27.7 -27.7 but on the other end
> > of
> > > diode 105 (which goes to P100 and others) reads +11.3 it should be -27.7.
> >
> > Where did you actually check for the -27.7 volts? It seems the transistor
> > Q101,
> > Q103 or ZD101 is defective.
> > Can you find out what the voltages are at the B, C and E of Q101 and 103?
> > If you get the right voltage (about -28.4V) at the E of Q101 (and thus the B
> > of
> > Q103) Q101 should be ok. Then check Q103 to see it is actually receiving the
> > main 33V at it's Collector. If these two requirements are met then Q103 is
> > probably failing (because at the Emittor of this baby originates the
> > main -27.5
> > V, which is +12 V according you. Then the 12V you are reading there is
> > probably
> > the +27V minus a voltage drop from the 'positive half' of the XY amplifiers
> > ect.
> > since they are not negatively fed anymore.
> >
> > Normally a defective transistor/diode is short-circuiting, but in you case
> > is
> > prbably gone high-ohmic or a bad connection.
> >
> > I
> > > also replaced, checked and capped every component from the high voltage to
> > > the chasse transistors. I know it's not the high voltage section because
> > I
> > > swapped a know good one and still have the same problem. At this point I
> > 'm
> > > stuck I've been working on this for two months and have looked at every
> > > place on the net that has dealt with vector monitors, but to not avail...
> > >
> > > p.s. Also since I'm not getting the corect -27, the high voltage does not
> > > come up and the spot killer light stays on...
> >
> > You're roght, the HV cannot cause this I think...
> >
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> --
> Windows:
>
> 32 bit graphical interface for a
> 16 bit patch for an
> 8 bit operating system written for a
> 4 bit processor by a
> 2 bit company that can't stand
> 1 bit of competition.
>
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Received on Tue May 23 08:40:35 2000