Proto Sound 2 5v board repairs

@DaveGG posted:

I know this is a bit off topic, but is there a database of MTH engines that were supplied with the 5 volt vs the 3 volt PS2 boards?

I got this from MTH several years ago when I was trying to determine the status of all my MTH Locomotives if it is any help.

Thank you for contacting MTH Electric Trains. We appreciate your interest in our products. I am afraid I cannot give you an exact date or catalog where we switched from the 5-volt ProtoSound 2.0 to the 3-volt system. For the Premier engines (steam and diesel) in was primarily in the 2004 volume 1 catalog; the majority of the engines offered in that catalog or after have the 3-volt system. For the RailKing engines the switch over was about one catalog later - the 2004 volume 2 catalog. If you have engines that were released around this time we can check on a specific models.

Go to the MTH site (while it's still there) and check the specific product number user's manual.  When you look at the battery maintenance, you'll see what kind of battery is there.  That's good about 98% of the time, but there are errors.  Another way is to simply look at the bottom of the diesel or the bottom of the tender for steam.  Round charging jack (or no jack) is 5V, rectangular 2-contact jack is 3V.