Here's the final word on my R2LC issue. I found an extra C08 board in a box of parts, installed it and now everything works fine. I did have one strange problem when I put it back together; all the TMCC functions worked fine but the board would not accept reprogramming of the ID number. Turns out that the Program/Run switch is on the bottom of the motherboard rather than being screwed to the chassis as it is on most units. It sticks through a slot in the chassis. The motherboard has some slop in the mounting, and it had shifted enough so that the switch was physically blocked from moving all the way to Program. I loosened the screws holding the motherboard, slid it around a it, and retightened it. Now it works fine.
One final question: might there be any possibility of reviving the board, or should I just keep it around in case I need a smoke triac or something? The symptoms were poor reception of commands. It would not always accept commands, and when it did run, it started very slowly and throttle response was delayed. This was with the brass tender shell off; with the shell on it wouldn't respond at all. I don't know what the replaceable components do. If one of them is an RF signal amp maybe that's the problem. If the main chip is bad, I assume that's the end.
