After several years and lots of learning and frustration, I am backing out of the TMCC repair business. Although I do like a good puzzle, I find some of the repair jobs to be very frustrating because I don't have enough information or parts are not available. Lionel now seems to have a nice line of "new and improved" power controller products that are probably a better investment than repairing some of the old gear.
I also find that repairs greatly detract from my time to do my own train projects.
If I really charged an appropriate fee for my time, nobody could afford my repairs. For example, just dealing with the initial contacts and preliminary diagnosis, receiving a package, billing and shipping the package back and receiving payment, without even considering any disassembly, repairs, assembly and testing involved, would rightfully run higher than what I have been charging for this AND the repairs.
I will continue to work through my backlog, but I don't solicit any new work.
Thanks to everyone who has worked with me. I am pleased to have been able to help most of you. I will still offer to consult with people to help them solve their problems. (I found that some of the bad devices were really OK, but either needed just a RESET or a change in how they were connected.)