Acetone doesn't touch potting nor does isopropyl alcohol. Like digging hard plastic. Vessel is cast aluminum. Devices are small AC generator voltage regulators that have failed and are no longer available no NOS. Craftsman and Generac regulators. Thanks in advance.

 

Try heating to > 80C. Depending on the compound, it may soften.

 

Hi, thank you. 80c won't hurt the caps so into the oven they go tomorrow. The stuff is colored black not green so hopefully an intact board can be recovered. I've got fingers crossed I can extract ID off of specialties like voltage comparators and op amp if any. I cannot imagine these things being more than basic circuits. A basic circuit that when available cost ninety to one hundred thirty dollars. Like buying a fan for sixty dollars and finding out a motor replacement cost fifty.
The Chinese lease containers and ship assembled products here at minimum cost in huge bulk quantities. But replacement components get shipped the expensive route. Like DHL or FedEx.

 

I recently dug potting from some igniters. I used a small sharp screwdriver to start then went with jewelers screwdrivers. It took some time. About two hours and damaged a couple of the devices within.
Heat did help but not enough to be useful in my case.
If I get them fixed though the savings are huge. Parts I'd has been the worst.