Re: Vector Monitor HV power...

>Wells Gardner did regulate the output, based on feedback from the 180v
>supply.

Oh, right. There's a lead off the primary that WG runs back to a little
three/four transistor regulator... The GO-7 transformer kicks back the same
180V off the primary, I was figuring to more or less cut and paste the
regulator. Might not work with a 120Vdc potential to the HV transformer
though-- maybe too much voltage for the junctions in the 3906/3904's?
Hadn't thought about that before...

>Amplifones use a completely different way of regulating their HV.

The mysterious "Magnetic Correction Device" or whatever the hell it's
called. ;-)

>The Amplifone does fall out of regulation during the explosion scenes.
>If you look at the +/-24v regulators used to regulate the inputs you'll
>see they are bypassed with 50 ohm resistors. During the explosions, the
>7824/7924 could not supply the amount of current needed. These resistor
>supply the additional amount of current during current peaks, though
>when they kick in, regulation is lost.

Ahhh, I seem to remember some discussion about that now. It looks to me
like the "easy" thing to do is replicate the Wells Gardner HV circuit
making the following "adjustments":

1) cross transistors to more commonly available ones where appropriate

2) use GO-7 HV transformers and 2SD870 HOT

3) use isolated 120VAC supply to bring main supply to +120DC instead of +-25V

4) double check/adjust HV regulator to be tolerant of 120V potential
(Probably be smart to see about getting rid of that 150V zener since
they're a pain to find, drop it down to something a bit easier to find...

I'm half-way tempted to bring in a WG HV cage and scan the PCB layout and
just make "changes" with Photoshop and try etching a PCB that way. :-)

-Clay

Clayton N. Cowgill Engineering Manager
_______________________________________________________________________
/\ Diamond Multimedia Systems, Inc. clay@supra.com
\/ Communications Division http://www.supra.com/
Received on Tue Dec 2 08:59:13 1997