erratic/limited control of TMCC engine

What is the item# of the engine?

i was afraid i might get asked that....purchased without box...see if I can track it down.

You don't even tell if it is steam or diesel.  Let alone manufacturer.  Could be poor continuity of AC power but coupled with poor antenna connection.  But depending on what TMCC is installed, Lionel, ERR, TAS, could be other issues too.  No simple solution.   

Start by removing boards and reseating properly, doing an ID reset along with engine type set.  Check antenna connection.  G

Runaways in TMCC usually result from failure of the cruise control magnet ring, sensor or wiring.  Here are some troubleshooting steps that I collected from some of the gurus on the forum.  If your locomotive  has Odyssey Cruise Control, your first step would be to turn it off (see below).  If that fixes the problem, then proceed with checking the magnet, sensor, and wiring.

Causes of runaway TMCC locomotives:

1. Loss of TMCC signal. If you lose the TMCC signal and then have a power interruption to the locomotive, the second time it gets power, it will run at full speed in conventional mode. (see Locomotive Signal Problems below)
2. Failed motor driver board. Try replacing with a known working board.
3. Odyssey Cruise Control problems.
   1. Turn off Odyssey (slide switch on engine or TMCC command Aux1, Brake, 7, Brake). If this fixes the problem, check the magnet, sensor, and wiring to the sensor. To turn Odyssey on, press Aux1, Brake, 9, Brake.
   2. Magnet: check for hairline cracks, broken or loose magnets (loosened from shaft)
   3. Sensor: check for improperly aligned sensor. The gap between the sensor and the magnet ring should be around 1mm.
   4. Wiring: check that the three wires from the sensor board to the DCDS are intact.
   5. Test the Sensor: With track power on, use a Multimeter to check for +5 VDC between the two outside pins of the 3 pin speed sensor plug at the DCDR-S board, as you rotate the flywheel by hand (the sensor has to be plugged in of course). The voltage should cycle from zero to +5 VDC and back again as the flywheel rotates. If so, the magnet and sensor are working correctly.
   6. DCDS motor board: Replace with a known working board

Locomotive Signal Problems

Antenna problems. In a diesel locomotive, measure the resistance from the handrails to the chassis.  Commonly the handrail is used as the TMCC antenna.  It should not be connected to the chassis.  Remove the shell and trace the antenna wire.   It will either be connected to the handrail or may be taped or glued to the inside of the shell.  If you don’t find it disconnected or shorted, try connecting a short wire in place of the antenna lead and run the locomotive without the shell. If that fixes the problem, you have a broken or shorted antenna.

In a steam locomotive, the antenna lead can be in the engine or the tender.  In the tender, it is either buried under the coal load or connected to the metal shell of the tender (which is insulated from the frame).   In the engine, one of the handrails is used as the antenna (insulated from the shell).  As with the diesel loco, make sure there is no continuity from the antenna to the frame.   A common problem is the brass tender shell shorting out to the frame.   Often, the only insulation is electrical tape. To verify an antenna problem, try connecting a short wire in place of the antenna lead and run the locomotive without the engine or tender shell (wherever the antenna is located.  Antennas function better if separated from a grounded chassis or shell.  Even a ¼” separation can help.  Use as long a wire as is practical.

Failed board connections

Check if board is seated properly and retest.  Then pull out the board, check for broken pins and connectors on the motherboard and the TMCC receiver.  Note:  Whenever removing/replacing boards, be sure to line up the 24 pin connectors properly. They can easily get offset by 1 pin, which will burn out components when you power up.

Failed Radio board

If the above procedures fail, then the likely problem is a failed R2LC or R4LC radio board. Replace with a known good radio board.

Here is a link to GRJ's similar advice to a member with a runaway locomotive.

Bob

@msp posted:

i was afraid i might get asked that....purchased without box...see if I can track it down.

As mentioned, how about some specifics on the locomotive.  If you don't have the actual model number, the exact type of engine is a great help, not to mention pictures help a bunch.    Usually, with the exact engine type and road name & number, we can figure out what model it is.  Obviously, pictures of the problem child help as well.

As others have stated, it sounds like you may have two problems.

• The Odyssey I seems to be not working, that's usually the magnet ring on the flywheel, but it can also be the wiring to the DCDS motor driver, or the DCDS board itself.
• The stopping on the layout sounds like a TMCC signal issue, first thing to check is the antenna, then swap out the R2LC with another engine's board to see if the issue follows the R2LC board.

Okay item # and Pic as requested.  

Lionel 6-18293 Santa Fe U28-CG Powered Diesel Locomotive #354

Let me update the post.  I did a reset...that helped kinda.....What it is doing now.

I can run at 13 volts at a reasonable speed.   So not sure if i would characterize it as a runaway engine to RRDOC post.   With that said my only control is stop and go.  

What has changed since the reset.   When the engine stops - I now no longer have to push it off the location to get it going again.  Turning the red knob will mostly get it going again.  Sometimes direction button twice and it starts up again.  

Just to be clear - discussion about the antenna....it is stopping basically right under my nose....It will run on the loop that goes into the attic (behind a wall) and come out successfully some 15 - 20 feet away.   I can be within 2 feet and it will stop.   Don't know if that is relevant but it seems it would be the reverse

I have noticed since the reset...the lights don't flicker like they were...except when it stops - which goes to the signal issue.   But again, why poor signal close and not further - that is for you tech guys.

So to summarize,  I can run it fine in conventional,  It seems to be running half convention half TMCC for lack of a better description.  I can go on / off with the remote and have to baby it as it wants to stop.  Can't control speed at all with the remote...half to control speed with the transformer

I am not going to be pulling this apart unless it comes with pictures and a beginner level project.  I will live  with it /run it in conventional until I can get someone to look at it.

Oh and I think TMCC base and remote are fine as I run other TMCC Lionel engines successfully.

Thanks for the input

After some more running session I can break it down pretty simple I think.

Like I said above - half conventional/half command.   Can't control speed with remote only the transformer.   Remote is start/stop.  Can control bell whistle and coupler with the remote.

It is starting to vary its stopping points on the layout...was consistent prior to tonight.   Tonight running right through old stopping points and finding new stopping points.   When it stops....just keep turning red knob until it goes again.

I understand your hesitation about pulling the locomotive apart.  The bundles of wires and circuit boards is a little intimidating.  But there are things you can do without cracking the shell.

Here is Lionel's listing for your locomotive.  It does have Odyssey Cruise control.  I would first turn off Odyssey as described in my post above.  If it resolves the problem, then you have a magnet/sensor/sensor wiring/motor driver board problem.  

If it does not resolve the problem, then I would next be looking at signal issues.  When the locomotive stops and lights are flickering, sometimes holding your hand over the locomotive will restore the signal and stop the flickering.  This can be a useful confirmatory test.  Also clean the wheels and rollers (and track in the problem areas).  

Usually (but not always) layout signal problems affect multiple engines.  You stated that 2 other TMCC engines run fine.  But here are a couple simple things to check to improve TMCC signal.

1.  Make sure the Command Base power supply is plugged into a 3 prong grounded outlet.  A 3 wire extension cord is ok, but a power strip is not.  (BTW the power supply must have 3 prongs)
2.  The signal connection on the command base must go to an outside rail
3.  Plug a long extension cord into a 3 prong grounded outlet and lay it along the problem areas of the track about 2-4" away.  (don't plug anything into the extension cord).  This extends the ground plane of the house wiring which improves the TMCC signal. If this fixes the signal problem, we can talk about a more permanent solution.

George's suggestion about reprogramming the engine type is another simple thing to do:

STEP 1: Move switch on locomotive from run to program.
STEP 2: Turn on Command Base.
STEP 3: Place locomotive on track, then turn on power to track.
STEP 4: Press “ENG” then input the locomotive ID# that you want to use. Press “SET”.
STEP 5: Press ”ENG” then input locomotive ID# again.
STEP 6: Press “AUX 1”, then "8" (this is the reprogramming code number for diesels with smoke).
STEP 7: Turn off power to track, wait ten seconds.
STEP 8: Remove locomotive from track, move switch from program to run.
STEP 9: Place locomotive back on track. Turn power on to track.
STEP 10: Press “ENG” and ID#, then operate as normal.

Bob

Thanks Bob, I will work through these suggestions and be back hopefully with good news.

@RRDOC posted:

I understand your hesitation about pulling the locomotive apart.  The bundles of wires and circuit boards is a little intimidating.  But there are things you can do without cracking the shell.

Here is Lionel's listing for your locomotive.  It does have Odyssey Cruise control.  I would first turn off Odyssey as described in my post above.  If it resolves the problem, then you have a magnet/sensor/sensor wiring/motor driver board problem.    Turned it off as describe above did not solve the problem.

If it does not resolve the problem, then I would next be looking at signal issues.  When the locomotive stops and lights are flickering, sometimes holding your hand over the locomotive will restore the signal and stop the flickering.  This can be a useful confirmatory test.  Also clean the wheels and rollers (and track in the problem areas).   holding hand did not work.   stops in areas I can't get to so couldn't do it every time.  tried the hand couple times to no avail  Cleaned tracks roller are shiny - looks like it has barely been run

Usually (but not always) layout signal problems affect multiple engines.  You stated that 2 other TMCC engines run fine.  But here are a couple simple things to check to improve TMCC signal.

1.  Make sure the Command Base power supply is plugged into a 3 prong grounded outlet.  A 3 wire extension cord is ok, but a power strip is not.  (BTW the power supply must have 3 prongs)  Yes there is whole other thread trying to figure out why my 2 prong plug wouldn't work - so got the three prong....
2.  The signal connection on the command base must go to an outside rail  Yes
3.  Plug a long extension cord into a 3 prong grounded outlet and lay it along the problem areas of the track about 2-4" away.  (don't plug anything into the extension cord).  This extends the ground plane of the house wiring which improves the TMCC signal. If this fixes the signal problem, we can talk about a more permanent solution.

Did not seem to make an impact still stopped.  

George's suggestion about reprogramming the engine type is another simple thing to do:  Have done this twice

STEP 1: Move switch on locomotive from run to program.
STEP 2: Turn on Command Base.
STEP 3: Place locomotive on track, then turn on power to track.
STEP 4: Press “ENG” then input the locomotive ID# that you want to use. Press “SET”.
STEP 5: Press ”ENG” then input locomotive ID# again.
STEP 6: Press “AUX 1”, then "8" (this is the reprogramming code number for diesels with smoke).
STEP 7: Turn off power to track, wait ten seconds.
STEP 8: Remove locomotive from track, move switch from program to run.
STEP 9: Place locomotive back on track. Turn power on to track.
STEP 10: Press “ENG” and ID#, then operate as normal.

Bob

UGH!  

Distance to you is not a significant factor.  The CAB controls the TMCC Command box and that communicates on the rails.  Lowering voltage so it is manageable doesn't mean you don't have a motor controller problem.  If it only goes full speed or stop when voltage is 18V there is a problem in R2LC or ODY set up as mentioned.  G

Okay thanks for all the help.