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Hi there

i have a 3rd rail/sunset loco with tmcc.  

in conventional operation speed control is perfect

however, once connected to the legacy controller and operated in cab-1 mode, at the first click of the knob it immediately goes to full power.  

Am I missing something with the setup or is the speed control circuit on the tmcc board shot?

thx!

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What model?  How new?  If this is the older model with the TAS EOB, it's probably the tach reader, usually a broken wire at the base.  If this is the newer version with the ERR Cruise Commander, try reprogramming the TMCC ID and engine type, typically AUX1/4 for 3rd Rail steam and AUX1/8 for diesel.

I think early 2000s.  I’ll check the board for the loose wire and report back   Thank you!

Hi john.   Didn’t see any loose wires.  the tender does have a cruise switch so I believe it’s ERR CC.  

i reprogrammed to no help.   Any other thoughts?  

fyi. I tried reverse and that was a bit jerky, but still moved slowly without going straight to full power.    Forward was still full power only.   Looks like the loco was made in 2003

Last edited by vacuefactor

Still not sure what you have and I’m not familiar with 3rd rail steamers. Is this engine new to you ?

EOB  did offer a cruise on off switch. In a 3rd rail engine. The early ones I think had a chuff switch to select 2 or 4 as well as the program switch. Is the switch clearly labeled cruise, on , off.  You can also disable the cruise with the remote. That would rule out the tach reader.  Eng. + # + dir. + aux 1 + aux. 1 + aux. 1 + 3 . The whistle should blow after the 3rd aux. 1 and after 3.

I probably can’t offer much help here. But I believe the guys here that can. Need a little more info as to what’s in the engine. I know the early 3rd rail engines came with a SAW board. If you purchased it second hand someone might have done an upgrade.

The runaway is classic for the TAS EOB, it's one of the most common complaints, and 90% of the time it's associated with the tach reader. Either the wires break (most common in my experience), or the tach reader gets dislodged from it's mount on the motor.  They can go bad as well, but that's much less common.

Runaways can happen with the ERR Cruise Commander as well, occasionally the R2LC loses it's engine type and causes the runaway, reprogramming usually fixes that.

The runaway is classic for the TAS EOB, it's one of the most common complaints, and 90% of the time it's associated with the tach reader. Either the wires break (most common in my experience), or the tach reader gets dislodged from it's mount on the motor.  They can go bad as well, but that's much less common.

Runaways can happen with the ERR Cruise Commander as well, occasionally the R2LC loses it's engine type and causes the runaway, reprogramming usually fixes that.

I took a picture.   The only thing I can see that’s out of the ordinary is the thin black wire looks like it was crushed.    Can you see anything else or want to see anything else?  

the board in the tender is one board with 3 mini boards

4CC26880-F92C-422B-AFB5-38B087D0AD29

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  • 4CC26880-F92C-422B-AFB5-38B087D0AD29

If the gap between the reader and the tach strip gets to great you can end up with a runaway engine. Just wondering looking at the picture. The reader is spaced and should be glued to the motor. The cable ties look a safety net to hold the reader to the motor rather than secure any wires. If they are really taught and they are the only thing holding the board on. It could be it’s out of adjustment. The manual has the adjustment at .030  .

  Were you ever able to disable the speed control ?  I know on most installations you also use the tach reader to determine the chuffs. If you run it with the speed control off and it runs fine. Take a note as to what the chuffs are doing. Not sure if this was a factory install in which case they may have used a cam on the tender and a switch to trigger them.

The sensor is mounted on an angle at least to my eye in the first pic. .  In one of your earlier posts. You mentioned it ran slower in reverse just not smooth. I’d cut the ties and see how secure the glue is holding it. Going by the pictures it looks like the ties are doing all the work and it looks a little out of adjustment.

Looking at it again. I’m not seeing any styrene spacers holding up the tach reader. I am seeing what looks like masking tape to insulate the board from the motor ?

Last edited by Dave_C
@Dave_C posted:

The sensor is mounted on an angle at least to my eye in the first pic. .  In one of your earlier posts. You mentioned it ran slower in reverse just not smooth. I’d cut the ties and see how secure the glue is holding it. Going by the pictures it looks like the ties are doing all the work and it looks a little out of adjustment.

Looking at it again. I’m not seeing any styrene spacers holding up the tach reader. I am seeing what looks like masking tape to insulate the board from the motor ?

Yes I agree with everything you’re saying.

the wire ties are very tight, and I suspect the masking tape is the insulation now that you mention it.  

will cut ties tonight and remount with a few styrene strips to see what that does.

thanks!

Looking at the pictures again. I noticed a Phillips head in the second picture. Seemed odd. Looking at the 3rd picture it looks like it was put there to raise the board up a bit. Not ever seeing a 3rd rail factory installation I can’t imagine it would look like this.
In the TMCC part of the Forum. There should be a permanent post with pdf documents of instruction manuals that will show the correct install.

Ok. So the LED blinks with every passing bar of the flywheel.  

also, the flywheel is not fixed to the shaft.   I can pull it right off and when I ran the loco it spun off the back end.   Is that supposed to be the case that it’s loose?

before getting into anything else just want to confirm that’s how it’s supposed to be?     Otherwise I’ll affix it first and then go from there…

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