I am trying to help a friend of mine fix the electronic podium for his church. It worked fine for years til they brought it to someone (not me) to change the rechargeable battery. He changed the battery but now as soon as you plug in the podium top condenser mic, you get uncontrollable feedback. It's like the volume control is turned all the way up. They changed mics and it does the same thing.

I thought maybe the pot went bad but it doesn't seem so. Any thoughts on how to troubleshoot this? I can't find a schematic. The model is Anchor Ensign model TL-28.

Thanks!!

Paul