Pengo power supply question

[Mark Czarnowski]

Hello,

I recently purchased a Sega Pengo machine, that is in great condition, and
very clean, inside and out. The previous owner had it for several years
without incident, and told me it just stopped working one day. I have
troubleshooted to the point where I have determined the power supply is bad.
It is the original Sega/Gremlin linear PS from 1982. Voltages are not
consistent, and usually too low. Once in a while, the machine works
perfectly for about 5 minutes, then quits. ( I have actually been able to
play a few games.)

LED on PCB glows normally when the game plays, but the rest of the time is
either very dim, flickering, or not lit up at all. I purchased a second
(working) Pengo PCB to ensure this was in fact the same problem.

I ordered a switching supply, which will arrive soon. The question I have
is for anyone out there that owns a Pengo machine that has had the original
linear supply replaced with a switching PS. The 10-pin connector that goes
to the original supply uses 7 pins. In order from left to right, the wires
connecting to these pins: brown, brown, brown, (empty,) black, black,
black,(empty,) red, (empty.) From reading the schematics in the owner's
manual, and trying to associate that with the erratic voltage readings I am
getting off of the supply, it seems as the following wires carry these
voltages: Black: +5 V. Brown: +12 V. The single red reads +17.5 V, so I'm
unsure of this one. Readings were taken while disconnected from the PCB.

Any help or advice would be greatly appreciated!

Thanx!

-Mark

[andyr]

I believe the 'red' is supposed to be +12 and probably isnt used for much
more than the sound section on the board or maybe only the Coin Counters.
(You can trace that wire back to the PCB and then check the PCB pinout for
the valid voltage...).

Andy

[Mark Czarnowski]

Hey Andy,

Thanx for the tip!

I did get a hold of the pinouts on wiretap, and was able to trace them back
to the PCB.

I figured out (and should have known this before by working in electronics
in the past, but never on arcade power supplies) that the three black wires
were not 10.4 V, but rather ground. The three brown wires are +5 V, and, as
you suggested, the one red wire is indeed +12 V.

I cut the wires off the original power supply, hooked them up to my new
switching supply, and it worked like a charm!

I can now play Pengo!

Thanx again for your help!

-Mark

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