Twilight Zone
Bally, 1993WH20_Buzz Working on this now...quick question for a dummy like me...
How do I attach the two +18VAC wires from J501 to the UPC1237 board?
Does one wire go to the "+12V" connection and the other go to the "GND" connection? Or do I put them both to the "+12V" and leave the "GND" empty? I didn't see any noted on this, and it seems like something I could easily mess up 
Thanks!
Here are images of the board I got:
PXL_20210703_173953915 (resized).jpg
PXL_20210703_174004990 (resized).jpg
Can someone explain the Magnet doughnut in the ribbon cable of Rockwells post? I have read that ribbon cables do not like bending, and that looks like a serious case.
Quoted from Tophervette:Can someone explain the Magnet doughnut in the ribbon cable of Rockwells post? I have read that ribbon cables do not like bending, and that looks like a serious case.
Its not bent 
its wrapped around a ferrite bead, it will be there to pass emission tests to gain CE/FCC certification as the DMD can radiate high emissions due to the high clock rate.
I have now tried one of the UPC1237 boards in my TZ.
I have used a separate 12V DC power supply for the relay instead of the 18V from J501. Just to be sure not to interfere with the onboard electrics.
The pop noise when turning the power off still exists though. The power supply for the 1237 board does not turn off quick enough to avoid the noise 
Someone knows what to do to make the supply turn off immidiately when turning off the power?
Quoted from marschner:I have now tried one of the UPC1237 boards in my TZ.
I have used a separate 12V DC power supply for the relay instead of the 18V from J501. Just to be sure not to interfere with the onboard electrics.
The pop noise when turning the power off still exists though. The power supply for the 1237 board does not turn off quick enough to avoid the noise
Someone knows what to do to make the supply turn off immidiately when turning off the power?
you will need to use the ac voltage from J501 as it 'disappears' instantly when turning the game off.
If you use DC then it takes time to disappear due to the internal capacitors.
Cheers Bob
Quoted from marschner:pinballtoys
Actually I did try to use 12V DC from J115 (not regulated) but almost same result when turning off. Maybe a little bit better but not very much.
Should 18V AC be better?
ANY source of switched AC in the pinball machine will vanish instantly when the game is turned off. If you have an AC powered relay, it will open instantly to prevent the pop at power off.
If you search a bit, I think you can find an AC powered time delayed mechanical relay which will wait 1-2 seconds to turn ON after AC voltage is applied and then turn OFF instantly when power is removed. I know they exist because I bought one for Funhouse that I never installed.
Quoted from marschner:pinballtoys
Actually I did try to use 12V DC from J115 (not regulated) but almost same result when turning off. Maybe a little bit better but not very much.
Should 18V AC be better?
The unregulated voltage you tried has a stonking big electrolytic capacitor across it so will hold the voltage for a while after switch off - AC on the other hand vanishes straight away as there is nothing to maintain it.
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