Apologies in advance for these questions because I know they have been addressed on the forum, but my searches have not been successful.
I have a number of never been run PS-2 engines that have been in storage for 5 plus years awaiting a layout. The layout is now operational, wired to the letter per Barry's invaluable book. I don't know if the engines are 5 Volt or 3 Volt, but it is my understanding that if the engine is a 5 volt, it will have either no charging port or a round, barrel charging port. If the engine is a 3 volt, it will always have a rectangular, 2 pin charging port. Is this correct?
Second, I think I should replace the batteries with new batteries or new BCRs. Or should I power up and see what happens? Or should I power up only the 3 volt engines and replace the batteries only in the 5 volt (the 3 volt boards being more robust)? I don't look forward to replacing the batteries, but I will if that is the best way to go. Suggestions please and I thank every one in advance.