@Jim Sandman posted:If it is a 5v Proto 2 please check the speaker for flaking as well, if it looks like dust on the magnet - do not power up until you replace the speaker!
Jim
to add,
If it's a later 3 volt PS2, I'd try it. Charge it though. Then do a test by killing power and see how long the sounds play.
It may cause different issues if the battery doesn't hold a charge. I would recommend having the external MTH charger and checking the battery after charging with that.
I have many engines that continue to operate with batteries over ten years old. It's just that they get undependable.
If an engine has issues, I always look at the battery first.
I've have had batteries fail early, that had a tough life. I bought them used and tried to guess at what happened to them. One engine of mine bought new, had long periods of no use and then the battery went early. I think it used to read a lower voltage around 2 volts if I remember correctly. Replaced it, and the engine has been fine ever since.