Re: TECH: Amplifone Q's

At 10:22 AM 10/6/97 -0500, you wrote:
>
> It was my first weekend in my new house (that I wasn't
>moving stuff in) so I was able to fix/try to fix a few games.
>
> The good news: My Star Wars now works perfectly (..and
>there was much rejoycing...yea, yea)
>
> The bad news: The Amplifone in my Quantum is really sick.
>I replaced the following on the HV board: HV transformer, BU406D,
>7824, 7924, electrolytic caps. I still get NO HV whatsoever. The
>deflection board seems good (I can hear clatter in the neck, AND the
>spot killer seems to be operating normally -- a little pulse when
>the game gets turned on, but then it goes off)
>
> The wierd part of it all is that the tube NEVER sparks,
>crackles, etc when I discharge it to disconnect the HV connection.
>It never sparks when I discharge it to re-connect the HV connection.
>In every monitor I've worked on, I've always been able to get some
>kind of spark/snap/whatever when I went to discharge it (even when it
>had just been sitting there, with the HV connection disconnected for
>a while....There also NO glow from the back of the neck (I even looked for
>thse sparks and glow at night.) Does this sound like a bad tube? There
>is no high-pitched whine from the HV transformer but there isn't from the
>WG HV transformers either, so I don't know if that is normal or not.
>
> I haven't checked voltages on the HV board yet (Remember, it
>was night time, and poking around on a HV board in the dark, while
>the monitor is on, is not my idea of a good time!) but will do that
>today.
>
> Any help would be appreciated...Thanks in advance!
>
>Joe
>
>BTW: Has anybody tried using the NTE cross for the SK part that is
>listed on Jess's page as a replacement for the HV diode in the GO-5?
>I don't think there is a place in town that sells SK parts, and I'd
>rather not mail order (I want my diode now, NOW!)
>
>------------------------------------------------------------------
>Joseph J. Welser jwelser@ccwf.cc.utexas.edu
>Design Engineer -- Crystal Semiconductor Corporation
>Ph.D. Student in E.E. -- University of Texas at Austin
>Work: jwelser_at_crystal.cirrus.com http://www.crystal.com
>P.O. Box 17847; Austin, TX 78760
>------------------------------------------------------------------
>
>

Joe-

I have had many tubes that had bad HV sections and never discharged at
all. I know that tubes are suppose to absorb (?) a charge from the
air, just sitting there, but I have not experienced that yet...

I am assuming you have another Amplifone, why don't you just try your
HV board in that monitor...

Mit
Received on Mon Oct 6 08:46:27 1997