Help with Lionel 6-34648 Legacy F3B not responding to TMCC

When this happened to me in the past, it was the R4LC board.  I've seen them go bad and I've also seen them have a bad connection.

I would start by opening the engine, pull off the R4LC and then reseat it.  Make sure the pins all line up so you don't damage them.

Here is a link to the Lionel Page with the picture of the R4LC (Item 36).

If the reseating doesn't work, I'm guessing the board will need to be replaced.

Seems kind of odd the R4LC would go bad during a lube job.  I do like the idea of checking the connections.  Another thing while in there is the antenna.  You had to flop that B unit over and over a few times.  See if the antenna swung itself and is now touching metal or a board.  Also reseat the antenna connector to the motherboard.  If all fails then swap the R4LC between the B and the A unit and see if the problem moves.

Thanks guys, I'll take another look inside it and check the board and antenna. I didn't bring the other powered unit home, so I'll have to wait to try swapping the boards.

Problem solved, even though the plug for the antenna was installed, the wire had a little vertical movement inside of its plug so it wasn't making good contact with the motherboard. It was fine if I pushed the wire back down, which worked until the engine was turned over to reattach the body. I just used a little bit of glue to hold the wire in the correct position, then plugged it back in when the glue had dried.

Matt,

That is great to hear!!