Help with a TMCC/Legacy Engine

Tom: After sitting on a shelf for the past nine years, there is a possibility oxidation has formed on the pin connections of the R4LC, I'd remove and then re-seat the R4LC being careful you align the pins correctly. A simple procedure and it might get you operating in TMCC mode again. Also be sure the antenna wire is connected and is not grounded to the chassis. Good luck.

You might take a look at the wires to the R-P switch to make sure that one or the other are not held in place only by silicone with no solder connection.

Ray

Thanks for the ideas.

Tried both. R4LC was removed and reseated. Antenna pin on R4LC to antenna has connectivity and the antenna to frame resistance is essentially infinite. The engine correctly responds in conventional mode as expected in either PGM or RUN switch setting. 

I guess my question is - Is this a classic R4LC failure mode? Or is it likely something else. 

If setting the switch to PGM doesn't lock the engine in a single direction for conventional mode, you have a problem with that switch circuit.

I wasn’t clear enough. When I said it operates as expected in conventional - I should have said in RUN it cycles through operating like a traditional Eunit. In PGM it is fixed in one mode. The horn and bell work. But in neither switch position do I have TMCC responses even though I know the TMCC signal is at the track (other TMCC engines operating as expected). 

So I had focused on the antenna connection and isolation and reseated the R4LC a few times. 

Even though I have a good many TMCC items I’ve never had a radio board failure.  I’m trying to understand if this issue is likely a radio board which I can replace or something more complicated the needs a Lionel service type. 

Well, if you've verified that the antenna is not grounded, and that it actually makes a connection to the antenna pin of the R4LC, next step is to swap out the R4LC.  If you'd like to see if the antenna makes it all the way to the R4LC, it comes in on pin 23.  The red arrow points to the antenna pin, the blue arrow points to the square pad that indicates pin #1.  This is looking at the back of the R4LC.