Terminator 2 sound issue

[qbert101]

I had recently bought and fixed up a terminator 2 arcade game. Everything works perfectly but the sound sometimes. When I boot up the game everything works, the sound, the monitor, the guns, but when I start the game the sound will kick out and make a humming noise. I can go into test mode and cycle through the sounds and reboot the game. And the sound works entirely for the entire game. Does anyone know how to fix this?