game 1 sounds like it is working but the ram is corrupted because of lack of battery / nvram

game 2 could be the reset, but likely something else. If p40 of the CPU is high your reset circuit is probably OK.

The manual should tell you what solenoids are controlled by what transistor. With that can figure out which ones are unused if you want to borrow transistors. If some solenoids never fire but most work make sure the driver board connectors solder joints are not busted on the left side (where all the solenoid stuff is). Look for a broken bus wire under PF too. Grounding the tab of a non working solenoid to see if it fires is a quick test of the wiring connection circuit is complete. If the solenoid kicks when you ground the tab of the transistor but does not kick in test or game mode means there is probably something wrong on the driver board.

There are settings related to sound so double check those. Missing background sound could be related to a bad driver board solenoid circuit. Double check the connectors including the nine pin one on the left side of sound board.

Have been more than a couple posts about people having trouble with getting background sound in flash. There might be old sound ROM versions out there or maybe some games are wired different. Might want to check the nine pin out of the left connect on working sound board and compare to the game acting up. Also compare sound ROM label. The proper sound ROM i know has background sound should say 'SOUND 1' and board jumpered for a 16K E/ROM (compare jumpers).

Rotating sound boards and driver boards might help isolate too.

https://www.ipdb.org/files/871/Williams_1979_Flash_Manual.pdf
around page 29 for solenoid info