I would like to thank all who posted on this topic of Data East noise solutions. As a new member i find this forum a great asset! I just purchased a Data East Time Machine. The background hum was taking the fun right out of playing this awesome game. After reading all 441 posts on this thread I decided the most sensible fix for me was just adding a small extra power supply dedicated to the sound board. I mounted it right next to the bottom speaker as it was easy to wire to the switched 120 v from the machine (as shown in the photo). From there a nice wire up to the soundboard with my +5 +12 and -12 then into an oem connector and problem solved. 20 dollars worth of parts and 1 hour install start to finish. The parts were obtained on Ebay and the description and part numbers are as follows.
Mean Well RT-50B PWR SPLY,SW ENCL,50W,+5/4A,+12/2A,-12/.5A, UL/CUL/TUV/CE 14.95
CT156F22-6-CA PANDUIT PANCON MAS-CON THROUGH CONNECTOR 300V AC/DC 22AWG 4.95

Thanks again for everyones help

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Sorry for delayed reply. Here is a photo of the sound board with new connections. Matching connections are on previous post showing power supply mounted in bottom cabinet. Note the wires that power the new power supply are from the switched section of machine So the power supply turns on and off when the machine is either on or off.

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