if you removed the battery or ram you probably reset the sound settings. there is a software setting (don't remember which number it is) that sets between tones and sounds. Check that first and then reseat connectors

Run self test (button inside door), set locations 16 and higher to '03' to get all the sounds. Change the settings by holding the start button.

Try hitting the reset button on the MPU and sound board. Also, the lamps are controlled by the lamp board.
The MPU should tell the sound board when to make a specific sound, such as when a switch is hit.

Also make sure the ribbon cables are on correctly.

Yes, If they light up at all, then the SCR & the associated decoder is working right. Can you cycle through individual bulbs in test mode on Xenon, or do they all just flash at the same time?

All controlled lamps flash together. That era of bally doesn't have individual lamp testing.

If they're tied to the larger SCRs used for multiple lamps, it is more likely a connector on the line going to the associated decoder. If it absolutely is not the connector, then the decoder MIGHT be problematic, but they hardly ever fail. Although I have had to replace a few, but only after a trace vaporization.

For shoot again, I'd run a test game, activate the necessary targets by hand to get an extra ball.

Then wiggle the lamp connectors on lamp board. If you can get it to light, you've found your problem.

Second this. Also consider replacing those lamp sockets. Not hard to do. And will be a lot more reliable. The old ones are just plain corroded.

The other thought is the switch that triggers them to turn on in the first place. Any flaky switches in switch test? Beep-Beep-Beep-Beep. I hear that in my sleep from debugging bally games.