I started with a simple problem, two sets of bulbs only light in Test mode. When checking connections and swapping chips on the MPU I lost half of the sounds. The audio that does play (voices and a boing sound) are full of static and occasionally stutter. I did not touch either of the sound boards.

I read other posts about similar audio issues and I am more than willing to re-cap, but what could have triggered this? And for my education, what role does the MPU play in driving the audio? Is it possible I damaged something on the MPU that is causing this? Oh, and my bulbs still dont light! (The two at Ball serve and two on the left side, one by the small band tied to one in the amber tube).

Thanks for any advice or direction.

image_(resized).jpeg

Thanks all. You gave me lots of options to try before going in with the solder iron!

Gentleman, thank you! You are correct that the audio had reverted to minimum. I still have some lights that work great in test mode but dont light at any other time: Shoot again, ball serve, and the left two tied together. Isnt it safe to assume the SCR's are fine if they come on and flash in test mode. Any additional advice for that.

Thanks again.

I agree about the volatility of the lamp sockets, thats a project on my list
! but why do they work great in test mode? I think thedefog answered my question of this being the decoder. I originally assumed the driver was not receiving a signal. I reiterate, they do not light during game play or standby, but the minute you press the red button they all light up just fine. Maybe I should see if these bulbs are all controlled by the same decoder. Hmmm.

You guys are giving a new member immense attention and I cannot thank you enough.