Picked up a working Time Fantasy a few weeks ago. It plays and generally works, but the original sound bug it had, has now been joined by a new one, as follows:
PROBLEM 1) Sometimes, at power on, during attract, a 1-second snippet of the background music (Firepower drone) will play and loop repeatedly. If you cycle the audit tables and "reset" the game, the loop changes pitch. If you disconnect the power to the sound board and reconnect it, the loop continues.
When this is occurring, if you start a game there is NO background music... you get most of the standard game sounds, but a few are garbled. After a few minutes (5? 10? 15?) the sound fixes itself. And sometimes at power-on, the issue never even happens!
FIX ATTEMPT: All boards are original and relatively clean. No major hacks. I recapped the power supply and the sound board. The problem did not go away.
PROBLEM 2) After an hour or two or run-time with the recapped boards, now, sometimes, a "heartbuzz" of a 60Hz hum in a pulsating rhythm will appear. It may run steady state for a few minutes at a time. It may glitch for a few moments. If game sounds are being produced, it will interrupt them. If no sounds are being produced (silent attract), you just hear the "heart hum buzz". Sometimes the buzz increases in tempo and pitch and then goes away and all returns to normal. One time all sounds quit entirely.
Either problem may now appear at random, sometimes at the same time. Here is a video...