/diy/ - Do It Yourself

I have a 2000s era kids Spiro pinball machine I had in the attic I thought would be a good place to start with electronics repair.
It had no sound, but all other functions work. So I went in and tested the speakers with a function generator, and the power supply with my ociliscope. Both are fine.
I hooked up a 4ohm speaker with 4.7 ohms in series, and got some garbled sound for a second, but then nothing again.
I have the board out, and see it's a main processor under a large blob, and then what I think is an amplifier under the small blob in pic rel.
I mapped it out, and scoped the points going to the large blob processor from the small blob. But I don't see any signal that could be audio.

I tried putting 10mV into the amp and seeing if I could hear anything on the speaker. But, once that didn't work I've become pretty stumped.

Any ideas on what I should try next?