Looking for thoughts on Lionel TMCC R2LC/R4LC "radio boards" failure rate. Not a rant.

Did you try resetting the boards in question?  I actually find the R2(4)LC board to be fairly robust.  Sure, I've had failures, but I've also seen hundreds of locomotives.  They're not that failure-prone, at least in my experience.

I have probably replaced 10 R2LCs, no R4LCs yet. I only replace them when there is no motor drive (serial data?). If its just a triac, they get repaired, not replaced and are not inluded in the ten. Of the 4 boards in the old modular setup, radio, motor driver, two audio boards, its usally the radio board that fails. Rarely the others. YMMV

Pete

I repair plenty of the triacs, I don't consider that a failure of the R2LC as it's an external short/overload that takes them out.  I've only had a few that really failed.  Normally, I've found they simply don't receive at all, my most common failure.  A couple had the serial data dead, or motor drive issues.

Interesting; I could not "reset", to my knowledge, as I could not talk to the board/loco at all. When powered up, the RS came on as in conventional mode, and no communication was possible. It was not in Command Mode at that point. Acted like there was no antenna (there was; the new board works fine with the old antenna, which is under an ex-hopper car molded plastic coal load in the brass tender).

Not sure about the "triac" repair - how is that done? Where is it? 

There are five triacs on the board, four small and one larger one. They control two couplers, front and rear lights, and the large one is programable for smoke, or mars light, or cab light. Aux1 8 and Aux1 9 turn whatever is connected to that triac off and on respectively. Because they are relatively large through hole components then can be removed and replaced. 

Pete

The "can't talk to it at all" is the most common real failure I've had.  Here's the triac positions and the part ID.

I prefer the R4LC boards just for the fact ( and I and no one can explain why) I have one engine that has crappy reception with every spare R2LC board I have and works just fine with a R4LC board.  go figure.

I have seen several R4LC board failures, and I don't know of any reason they'd be less reliable reception wise than the R2LC.

gunrunnerjohn posted:

I have seen several R4LC board failures, and I don't know of any reason they'd be less reliable reception wise than the R2LC.

You got it backwards 

No Gary, actually I meant what I said.

 OK I'm confused now.  I had poor reception in one Weaver engine.  Tried like five R2LC Boards with no fix.  Only a R4LC fixed my issues. 

Gary, anytime you see this on a weaver or K-Line  usually it is blown traces on the motherboard.  I have seen lots of that.  Motherboards are cheap as dirt but just follow the burned traces and hard wire the board.  Usually on power and ground.    The K-Line diesels are the worst.  I keep a few hard wired boards handy to swap out.  I get to see many R2 and R4 board locomotives.  I can not say if one is better than the other.  You can always take the RS power board to the bank when sound stops.  I replace that board more than any other board.  That board is the board that is used with TMCC and Legacy.

Gary, I have seen a few R2LC boards that stand tall in the test fixture and don't cut it when inside the locomotive.  That sends me looking at traces.  Remember those motherboards are getting old.

Here is a motherboard from a K-Line GP-38 from a week ago.  Engine ran but not dependable until rewired.   Many an R2/R4 board has been blamed for this situation.  I have seen guys order motor driver boards and throw money away.   Take the time to look under the hood before you order parts you may not need.   This situation exist.  You will notice it is usually on pins 1&2 (hot) and 2&4 (ground).

On these TMCC mother boards I would rather have one hard wired than a new one.

This is a fairly new engine with ERR cruise in it.  Everything is fine with the R4LC installed.

Gary, what engine do you have?

Marty, is that motherboard/burned traces you posted one where the front truck has a single roller plugged into one end of the m'board (say pin 1?) and the rear truck has the other single roller from the rear truck plugged into the other end of the m'board (say pin 2?) ?  Well, you get the idea.

I knew that that "convenient" arrangement had been used in the "modern" era, but I had thought that it had been brief and long since discontinued and avoided.  Is the board from a recent engine?

If so, I would attribute it to Chinese production engineering, where any perceived overuse of scarce copper (China began to wind its own turbines during the completion of the 3-Gorges Dam) could be severely punished by the central government.

As a historical note, in 1954 ("postwar era"), the then new Trainmaster was the first Lionel engine to use such an arrangement.  Shortly, the Service Stations were instructed to replace the two separate connections (to the single E-unit tab then) with much heavier flexible wire than they had been using in engines (strip a piece from the 3-c switch controller flat cable of the time).  This was to be done anytime they saw a Trainmaster for any reason.  That is, the rollers were to be bridged by something that could not be burned in half or damaged within the opening time of the transformer breaker, at various fault currents.

--Frank

On these engines, both front and rear trucks have roller and ground feeding the board.  The board was at the end of K-Line.   I have worked on many of these.  I am also very familiar with the post war wiring.