I have a Williams Cyclone System 11b machine with some odd audio issues. The game plays well, however after 30-40 minutes, the music will hang on a single note and some of the sounds stop working. Some sounds work, which I’m guessing are the ones generated by the MPU. Music will come back on after a reset occurs (new ball). Over time it will degrade and it locks up very quickly, especially after going through the first switch at the top lanes of the playfield. Perhaps this is coincidence, but it was locking up and after having the cabinet open for a few minutes, it played well for 10-15 minutes and then started locking up again.

My voltage is a little low off the power supply, however I’ve read this will normally cause the MPU to reboot. The MPU is rock solid. 12v at test point 3 on the power supply is 11.57V and test point 4 is -14.71V. At the audio board on J3, I’m getting 4.845V, -14.68V, and 11.57v. Caps on the power supply were replaced in 2017.

Suspecting heat, I noticed the Yamaha sound processor at U3 was noticeably warmer than everything else. Using an infrared thermometer, it got up to around 145F. This seems pretty warm. I’ve reseated the audio data cable and even inverted it.

Any thoughts on further troubleshooting?