Thank you George, Dave, Marty. I have read a lot of posts about the PS2/3 kit, but it just didn't sink in until now. I have a couple engines with PS2 5 volt boards. I'm fine leaving them as is, but when one or both quit working, now I understand why the PS2/3 board.
Thank you EJc for posting your questions. I'm sorry you didn't find this information first.