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One of my (1st run) 3rd Rail E7s is misbehaving.  Experience suggests to me that its TMCC radio board, a R4LC-C, has issues.  Given that TMCC receiver boards are now essentially unobtanium, I somewhat hesitant to swap out this R4LC-C with other TMCC radio boards (R4LC-C08 and some R2LCs) that I have.  Are there incompatibilities between TMCC radio boards that one should be aware of?

The loco wouldn't move.  TMCC addressing and sound control worked.  I put it on the bench and opened it up.  At first, nothing worked.  When I came back to it a week later, everything seemed to work.  I repaired loose pickup roller assemblies and put it back together, testing at each step successfully, until I added the fuel/water tank piece.  Then multiple malfunctions manifested themselves, including the dreaded full speed upon throttle rotation.  Now the loco makes engine noise but TMCC does not control sound or motion.

Are we to the point where we will be acquiring older/cheaper TMCC engines just to harvest the radio boards?

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@Norton posted:

It could be just poor signal due to the shell touching the frame. Is this an older run of the E7s? Remove the shell and see if the symptoms persist. I believe you will find plastic grommets insulating the screws from the frame. Don’t loose them.

Pete

Nope.  Shell was off and isolated on the bench.  Grommets found, but I'm not sure where they were placed before disassembly.

The R2LC-C04 was the first version of the R2LC, I doubt it will work with the Cruise Commander.  The R2LC-C05 was only for the backshop.  The R2LC-C06 was first used in the early GG1, can't say if it's compatible with the Cruise Commander.

The R2LC-C07 works fine with the Cruise Commander.  The only difference between the -C07 and the -C08 was the -C07 was a special version of the -C08 code with the headlight polarity reversed in command operation, it was only intended to use in one locomotive.  This was done to accommodate the C420 production run that had the LED's wired with reverse polarity.  Rather than rework the entire run of C420 engines, they decided to just make a quick code change to reverse the polarity of the lighting outputs to fix the problem.   The -C07 is also a worthwhile version to keep in mind if you can't find any -C08 boards, other than the headlight polarity, it's the same as the -C08.

Never saw or even heard of the -C09 or -C10 anywhere, I don't believe they were ever actually used in anything.

The -C11 & -C12 were only around for a brief time and had issues with lashups.  The -C13 is the final version of the TMCC R2LC code and works fine with the Cruise Commander.

You might want to try disconnecting the ERR sound board, or at least try disconnecting the serial wire to it. If motor control is restored, it could be the serial line is being pulled down by the sound board. I had this issue in a 3rd Rail SD7 I fixed. It seemed to work ok on the bench and then acted like it had a bad antenna with sketchy control and flickering headlights when on the layout. Only diff between the bench and my layout is I run at about 16V for my test track and the layout is 18V. If I disconnected the sound it would run fine on my layout. I thought I’d have to use a serial line buffer but swapping the stock R4LC to an R2LC08 from my stash cured it.

At this point I’ve pretty much given up on keeping TMCC stuff alive beyond what my parts stash can support. From here on out it looks like Blunami will keep me rolling.

Last edited by Norm Charbonneau

The R2LC-C04 was the first version of the R2LC, I doubt it will work with the Cruise Commander.

I'm fairly certain the C04 had a specific purpose... might have been for the TMCC Culvert accessories.



Never saw or even heard of the -C09 or -C10 anywhere, I don't believe they were ever actually used in anything.

Correct. C09 and C10 were never released for production.

TRW

@PaperTRW posted:

I'm fairly certain the C04 had a specific purpose... might have been for the TMCC Culvert accessories.

I actually have a C04 board, it appears to be optimized for steam.  It doesn't accept the AUX1/x code to change behavior, and it has no coupler function.  However, it has smoke operation, including the boost, and smoke is automatically off when the motor isn't running.  It has constant headlight and taillight on in reverse.  It has standard motor control and chuff input is encoded in the serial data stream from the chuff input pin.

You might want to try disconnecting the ERR sound board, or at least try disconnecting the serial wire to it. If motor control is restored, it could be the serial line is being pulled down by the sound board. I had this issue in a 3rd Rail SD7 I fixed. It seemed to work ok on the bench and then acted like it had a bad antenna with sketchy control and flickering headlights when on the layout. Only diff between the bench and my layout is I run at about 16V for my test track and the layout is 18V. If I disconnected the sound it would run fine on my layout. I thought I’d have to use a serial line buffer but swapping the stock R4LC to an R2LC08 from my stash cured it.

At this point I’ve pretty much given up on keeping TMCC stuff alive beyond what my parts stash can support. From here on out it looks like Blunami will keep me rolling.

Thanks for the tip, didn't think of that, will check it out this morning.  This particular model uses Lionel Railsounds boards.

I'm not comfortable using the 4A Blunami in larger steam engines with Pittman motors (or worse), mainly due to measured current draw when climbing the 3% inclines of my layout.   Yeah, I know that Pete's had good results on a Hudson.  I will likely standardize on Blunami for diesel command upgrades, given the receiver board retirement. 

Karl, just to make sure when you removed the shell you left the antenna wire attached to the Cruise Commander? FYI there are a couple of ERR R4LCs on the sale forum attached to DC Commanders if you are pretty sure that is the problem. Also a new ERR CC would be less expensive than a Blunami and a 5 minute swap.



Pete

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