Help! TMCC C420 stopped moving

For starters, TMCC locos will not roll at all, only legacy equipped locos have "back drivable gears" that allow the to be rolled without power.

 

How are you operating it, conventionally, TMCC, Legacy? The more info you can give the better.

 

If under TMCC you can try the reset instructions in the back of the  locomotive manual.

 

If under legacy check the "train brake slider" if its all the way down, trains will not move.

Tim-

 

Are you using TMCC or Legacy? If you are using Legacy, check that the "train brake" sldier is pushed all the way up (to "-").

 

The wheels on most powered diesel engines do not turn freely due to the gearing between the wheels and the motor. However there should be a slight amount of free play, so if the wheels can rotate back and forth about 1/8" of an inch or so, a jam is not the likely issue. If the wheels do not even turn at all, or if you see foreign matter in between the wheels, then you might have a jam.

 

To clear a jam the easiest thing to do is remove the entire motor truck. With the advent of Lionel's Liondrive this is very easy to do - simply rotate the truck so that the sideframes are perpendicular to the fuel tank and then gently pull down to release the truck. Disconnect the wire harness attached to the truck and place the rest of the locomotive to the side. With the truck detached, you can rotate the wheels back and forth while inspecting for any debris; if any is found you can clear it by pushing on the wheels to get the jammed gears to reverse. If however there is evidence of broken/missing teeth or stripped gears, replacement parts may be in order. Since you have the truck apart, it might be a good idea to lubricate the gears and bushings per Lionel's instructions.

 

To attach the truck back to the locomotive, reverse the steps above. Connect the harness back, hold the truck perpendicular to the fuel tank, push up, then rotate so that the coupler points away from the locomotive's cab. You'll feel some resistance and then hear a click, indicating the truck is back on.

 

Good luck!

 

-John

At the time it stopped working, I didn't have any TMCC hooked up, just conventional. I hooked up TMCC after to see what would respond or to see if somehow it was stuck in command mode. I will try the reset you mentioned in the manual. Thanks RickO.

For the record I don't have Legacy just TMCC.

And the wheels do have play in them as you describe.

Tim-

 

It's a long shot, but since you are operating conventionally maybe the reversing unit is locked out in neutral?

 

-John

OK, I tried the TMCC reset but i wasn't sure if that applied since I was running conventional when it failed. Anyway....

 

-All lights and other TMCC functions work.

-When I hit the direction button on the remote. The lights turn off on one end of the loco and come on on the other end. This happens each time i hit the direction button so that seems fine.

-Horn works

-Other railsounds work

-RPM sounds change as I turn the throttle wheel.

-Power. I have power on the track. I can run a conventional loco just fine.

As I said before. I was was running this loco last night and this morning. Then it just stop the instant I hooked it up to a set of six cars. And that brings up questions about the electro-couplers but they are working too. (just to be sure, the coupler buttons only open the couplers right? They don't toggle between a opening and closing action?)

 

So if the next step is to remove the trucks or take the shell off, I need help. I pulled the 8 body mount screws but the shell doesn't seem to want to budge. And the trucks do not seem to be able to turn 90degrees like AcelaNYP suggested. It feels like I'm going to break it if I twist much harder. Perhaps this isn't a liondrive? I don't know.

 

Tim

I got the body shell off, It had some sticky tape seal that required a little extra effort. I'm looking for loose connections? Reseat some plugs?

 

I've pulled all the connections off and reseated them inside the shell. I also reseated all the daughter boards from the main board. No change. At least I didn't cause any new problems. I did not figure out how to remove the trucks. Is there something there worth looking at? Any other recommendations?

Thank you,

Tim

I believe he was mistaken about the " liondrive trucks" these are a newer design on legacy locos, not a design thats part of your TMCC loco.

 

Its much more involved getting these trucks apart, I'm more inclined to think its something electronic causing the problem,possibly a motor driver board?

Theres really no way something can get into the worm gear assembly and jam it.

 

Be patient with this forum, there are plenty of well knowledged folks that will be able to help. I wouldn't start taking things apart until the problem is narrowed down.

And the trucks do not seem to be able to turn 90degrees like AcelaNYP suggested. It feels like I'm going to break it if I twist much harder. Perhaps this isn't a liondrive? I don't know.

Liondrive became a standard feature on diesels around 2005. TMCC-equipped C-420 models produced after 2005 would be Liondrive equipped. The earlier batch of TMCC equipped C-420 models made around 2000-2001 would have traditional worm drives. The trucks on the earlier batch DO NOT twist off. My apologies for the confusion on this one.

 

If possible, can you provide the forum with the Lionel part # for the C420 in question? This might help narrow down potential troubleshooting options.

 

-John

 

 

Model 6-28507. Most recent catalog=2001.

 

Can you turn the fly-wheels on the motors with out any binding? (at the work bench, no power)

Yes I can turn the flywheels on the tops of both motors and the loco will creep across the bench.

Tim-

 

Thanks. This unit does not have liondrive. Since you confirmed in the previous post that the flywheels turn freely, you do not have jammed gears.

 

I was able to track down the locomotive's manual here, and saw an interesting reference on page 4 on locking the direction of the unit. I would double check to see the switch is in the "run" position just to confirm the R2LC (radio control board) is sequencing properly.

 

I was also able to pull up the exploded parts view of the locomotive from Lionel's website (available here), which should help you identify what part is what inside the locomotive. Unfortunately there isn't a wiring diagram available for this locomotive.

 

In terms of what to look for, I would concentrate on part #s 25 (R2LC receiver) and #8 (DCDR), as both parts are tied to operating the motors, particularly in the command environment. Also look at part #19, which is the motor itself. Make sure both wires to the motor are in good condition and are plugged into the DCDR. There is also a 4-wire harness that connects the DCDR to the locomotive's motherboard (part #18), so I would inspect that also. Any broken/loose wires or unplugged connections would be the likely culprit to the train not moving.

 

Also look for any wires that are loose/missing or appear to be unplugged. If you find any, take a picture and post it to the forum if possible.

 

Good luck!

 

-John

 

If you have any other TMCC locomotives, swapping the R2LC is a worthwhile experiment, that would eliminate one of the variables. The smaller four wire plug that goes from the DCDR to the motherboard should be checked for any loose or broken wires, that brings the motion commands to the DCDR.

 

If you unplug the motor plug, you could put DC on the motors and insure they run, though two motors dying would be really unusual.  I'm with the other opinions that this is either wiring or electronic.

I totally respect your experience so don't be offended as I pick your brain here. Having it broken stinks but I'm also very technically interested. I do not have another TMCC engine but if I did and I could swap out any component, why do you suggest the R2LC instead of the DCDR? The R2LC is a radio receiver? And I can use the remote and effect all other TMCC actions (that I know of.) so it must be receiving? I agree it's very unlikely both motor would go bad just like that so it seems one step back from there is the motor driver?

For the record, I looked through all the docs listed (just the titles) in the sticky threads for this forum and I didn't see any doc that looked like a technical review of the TMMC components and signal path overview. If I missed it can you point it out for me?

 

Tim

The R2LC sends the signals to the Motor driver, so it can be either, and the R2LC is an easier first step.  G

As GGG says, the R2LC is the "brain" and it sends the motion commands to the DCDR.  Also, like he said, it's a simple plug-in part.  If you had an extra DCDR, they're also pretty easy to swap, once they're loose.  However, you have to deal with the slightly messy thermal compound as a rule on the drivers.  What I do is take a spare DCDR out and just perch it on top with an insulator and run the wires to it, but if you're taking it out of another locomotive, it's a bit more trouble.

 

Basically, I'd say it's 98% likely that the DCDR, the wiring between the DCDR and the motherboard, or the R2LC is the issue.  Of course, this assumes you have done the reset previously recommended.

 

I don't know of a TMCC Overview document either.

I've seen the terms "reset" and l "reprogram" used separately on the forums. What I did was "reprogram". Using code 8 specified in the manual for my loco. If there is also a "reset" tell me how.

The "reset" or "reprogram", or "wave the stink finger" are all the same, you got it.  That's what I was suggesting.

 

Aux1 0 puts it back to neutral ready for forward.  Some call this a reset. While a reprogram sets the characteristics of the R2LC.  G

I have the Monon version of this engine, 6-28506.  Conventional control.

 

I've got all the same issues you're describing.  Same deal, it was running fine and then wouldn't move.  Got tired of messing with it and put it back in the box.  

 

I need to try some of the things above to see if I can get mine to work.  

If I buy replacement parts is there something out there better than OEM? Either for the DCDR or R2LC?

This may sound silly but put a new set of batteries in the cab-1.

I'm willing to try that, but this happened without any TMCC hooked up. Purely conventional.

I'm not aware of any conventional TMCC resets. The Run/program switch becomes a lock out switch.  If the last time the engine was run in command mode it should start up in neutral one time only in conventional mode. From then on  Lionel engine alway  start in forward in conventional mode.

 

If you have a command base is it unplugged for conventional test?

Not for the R2LC, but if you want an improvement in the running (once you get it running), installing the ERR Cruise Commander M in place of the DCDR gives you speed control.  You get really great low speed running, not to mention constant speed on curves and grades without constant throttle adjustments.

 

At least you got it fixed Tim, and posted the problem and solution!

 

I think there is at least one more person who may benefit from what you've found.