That would be great! Lithium Coin cells can be PCB mounted. The removal of the car battery then the hands free working I think could be an easy fix.
I will replace the big electrolytics -May be a lithium cell there. When I take mine out I’ll know wher to start probing and I’ll beep out the connectors - since problem sometimes goes to way tells me chips are working although o may still want to check the voltage regulators