Re: PC power supply conversion question

From: Kev <Mowerman_at_erols.com>
Date: Fri Apr 16 1999 - 12:42:03 EDT

  There is one other benefit from using a switching supply. Some games
(especially Williams ) have a fairly good chance of taking out parts on
the boards when the Power Supplys fail. The 5v may go up to 8-12v.
Switching supplies won't do this. This happened to me on my StarGate,
and I've heard of this from other people.

Yes I must agree with the Williams problems. Most of my problems seem to be
associated with the CMOS RAM not holding under a switching power supply mod.
I thought it had something to do with spiking or rapid decay of the +5, but
didn't make much sense to me.

I too have had all the 4116 RAMs wipped out from PS supply failures, from
what I've seen (2 times) the Bridge Rectifier on the Audio board shorts &
creates a loop (since most people use -5 for the -12 side of the audio).
Now I simply remove the Bridge & have had no burnt up RAM problems (not
saying it is the complete solution, still have CMOS problems).

Williams even sold a Crowbar protection board that slide on the pin
connectors of the original power supply & would shunt over voltage
conditions. So I would assume they had problems with this too.

I do use a JAMMA setup to test MCR board but don't mess with the audio.

Galaga seems to benefit most from the Switchers, Pole Position does too but
the hack I use keeps the audio amps on the regulator boards in place (Star
Tech Journal).

Kev Mowerman@erols.com >>REMOVE THE ? to REPLY

Looking for Pac-Man related hacks & Video Game Flyers

COIN OP PAGE -> http://www.erols.com/mowerman
Received on Fri Apr 16 11:53:56 1999

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