This thread is a bit long but might be related to the jump sound not cutting off. This was my thread and supposedly transistor Q4 or Q6 can solve this problem. For me, it didn't.
https://forums.arcade-museum.com/showthread.php?t=364831
Long story short...here is the sound mine makes:
https://www.youtube.com/watch?v=gaapqFJ32Co
I have tried just about everything and still can't pin the issue down. Here is what i have done:
1. Capped the monitor
2. Replaced the audio amp with a repo from twisty wrist (now using a totally separate 3rd party amp)
3. All New audio caps on the audio portion of the CPU board
3. All new transistors on the audio portion of the CPU board (including Q4 and Q6)
4. All new capacitors on the power supply (this was a lot of work)
5. I even replaced the DAC08 chip altogether and that didn't fix it.
I about to ship my PCB off to an expert on KLOV to have it fixed because I'm about to give up.
As for the background hum sound that all Nintendo games seem to make...that is a super easy fix and you can read about it here:
https://forums.arcade-museum.com/showthread.php?t=388792