Re: Bizarre Amplifone Problem

From: Jeff Hendrix <jeffh_at_diac.com>
Date: Tue Oct 21 1997 - 11:25:08 EDT

I had the same problem with one of my star wars.
It turned out that the EPROM on the vector generator board was bad, I
swapped in a good one and everything was happy again.

-jeff

>Hey all,
>
> Here's a real stumper (or maybe not...)
>
> The background: I have a good Amplifone Deflection board, a
>good Amplifone HV board (both tested by me, in my Quantum Cabinet,) an
>untested Amplifone tube, and a Star Wars cabinet that has a perfectly
>good and working W.G. monitor in it (i.e. the Star Wars game is 100%
>working)
>
> I'm sure you see where this is going. I put the tube into the
>Star Wars, hook the good boards up to it, and no workee.
>
> I get a picture, and the vectors are razor sharp and beautiful,
>but they don't even come close to lining up. The "Star Wars" is just a
>jumble of blue vectors, and you can tell that there is supposed to be
>text after it, but all of the characters are unrecognizable. Basically,
>all of the vectors are royally screwed up.
>
> I checked the connections at the harness, and they were OK.
>Since this seems like a serious deflection problem, I checked the
>voltages across the deflection coils -- I got 24 VAC across one of them
>(the one that uses the brown and blue wires from the def. board) and
>12 VAC across the other (the one that uses the yellow and red wires.) I
>don't have the schematic in front of me, so I don't know which is which.
>
> Just to make sure nothing blew out when I hooked it up to the
>new tube, I took the whole mess (both boards) back to my Quantum and it
>fired up just fine (with good vectors.)
>
> Is there any defect with the tube that could cause it to display
>wierd vectors like that? I would think not (maybe a defect with the
>yoke?) but I've checked and checked and checked the connections and the
>boards, and I really can't figure out what's up.
>
>Any help would be much appreciated. This one's got me really scratching
>my head....
>
>Thanks,
>
>Joe
>
>------------------------------------------------------------------
>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
>------------------------------------------------------------------

jeffh@diac.com

Buy/Sell/Trade classic video arcade games.
www.diac.com/~jeffh/
Received on Tue Oct 21 08:26:38 1997

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