Lionel PRR M1a - issue

Making sure all the plugs are in correctly and antenna is installed.  Could try reseating he boards.  Which model #, Lionel may have a wiring diagram on the service link you can trace out.  G

6-38056.  The other thing to add is the motor seems to be humming. Like it is getting power but does not want to turn.

Could it be a binding problem either with the drive shaft from the motor or the gear box drive rod assembly?

I agree with Charlie, Will it do the same when changing directions.

Bill

I thought the same, but the engine will move if I stick my finger and move the flywheel. There are fake brake shoes, I thought those were binding too so I removed all 6. I even unclipped all the wires from the zip ties to free the area. I did notice that the firebox LED do not light. They usually glow as the engine runs.  I think it is electrical, and I separated something. There are 5 Leds on a board inside the cab. They do not flicker.

Will the smoke or headlight work or markers if applicable.

Bill

yes, smoke turns on and off. Whistle, bell, all the railsounds, even the rear coupler. But no throttle when the cab-1.

Did you remove any of the wires to the DCDS motor driver board?  You may want to make sure the 4 pin and the 6 pin molex are plugged in completely and correctly.  To test the motor you could remove the 6 pin molex from DCDS and power the motor with a 9V battery to make sure it turns fine.  G

  Do what George (GGG) told you to do to check the motor first.  Is the flywheel tight on the motor shaft?  If it is not, secure it and try to power up.  Does your flywheel look like this?  If the magnet ring is broken off (very common)  the flywheel  you will also have what you have.       If all those things are in place, let us know and the Odyssey speed sensor will have to be tested and the wiring back to the DCDS.            

I solved the railsounds issue by moving from the engine to the tender. The PCB board in the tender is the issue, if I wiggle it, the railsounds cut on and off. Does that board have anything to do with power to the motor. I think it is a power issue because if I have power to the engine all the railsounds work. If I turn the flywheel with my finger the entire engine and tender moves forward, and the railsounds chuff if I go about 6 10 inches, very slowly.  It is like the motor is not getting power.

The engine and tender have there own power source from the track and can work independently for basics.  The Command board is in the engine, and it transfers serial data to the tender via the drawbar IR sensor.

You can have loose boards in the tender.  So pull them off one at a time and reseat them.

Since the R2LC can transmit signals to the tender the draw bar is fine, but as far as the motion of the engine that is all confined to the engine.  The R2LC sends signals to the DCDS for motor control, and the DCDS converts the AC power to DC and drives the motor. 

You can swap R2LC to find out if the motor signals from it are the issue, you than have to swap the DCDS to see if that is the issue, then test motor, than test the harness from the DCDS to the mother board and power source.

You can have a broken wire under the insulation of the 6 pin molex as an example.

Tender has nothing to do with engine functions.  That is self contained in the engine just without sounds.   G 

I have swapped the R2LC and tested both ways in a K-line K-4. So that board is good.  There is a brown and gray wire that goes from the poles to a black plug. Those are the power for the motor. There is a green red and one other color, that goes to the top of the motor and controls the chuff.  Can I put power to the motor directly and bypass the boards? 

  The chuff is controlled by ground pull up from the cherry switch.  The wires on the plug on top of the motor are for your Odyssey speed sensor.  Your motor wires if you trace them go to the 6 pin Molex plug located in the canter end of the DCDS.  One last time,----is your flywheel ring intact?  If so, is your flywheel tight on the motor shaft?  Have you checked for a broken wire on the 6 pin Molex like George stated?  Nothing is wrong with your R2LC and the DCDS is a strong component, they do go but that is not what is showing.  Is it possible you can answer my questions so we can help you??

BTW, the other color should be yellow.

If you test the motor with a battery you need to unplug the 6 pin molex.  You don't want to put DC back through the DCDS as a basic principle.   G

I would check the 6 pin molex connector for AC hot and AC ground. The clue is the firebox flicker not working.

Bill

Flywheel is all one piece. I will post a picture shortly to be sure we are on the same page. I unplugged and replugged the molex. Unplugged it again, brown and gray wires put a 9volt and the engine runs. The flicker comes from a 10 pin plug on the right.

Correct on the flicker.  It gets 5V and ground from the 10 pin plug.  Take your continuity meter and go from the grounds on the 10 pin to chassis ground and see if you get continuity.  Looking at the 10 pin from the side going from L-R pins 4 and 8 are ground.  Pins 3-7-9 are +5VDC.  Now check the 3 pin plug that is next to the 10 pin.  The pin closest to the 10 pin is your +5VDC input.  Check to see if you have 5VDC at that point.  If you do not have +5VDC at that point, check for +5VDC at pins 19 and 20 on the R2LC.  Let us know.  If you do not see +5VDC some engines used an external reg to put +5VDC. 

You beat me to it Marty.

Bill

Sorry for the delay in getting back, i did post something now I can not replicate. let me look again.

Are you getting any reading at the 10 pin? 

10 pin has no reading on voltage.   continuity on the 10 pin is between .8 and 1.5.  turned transformer down to about 5 volts and touched wires that go to the flicker on the 10 pin and the lights work.

Bill, I have seen them both ways.  The easy check is to check continuity between 19/20 and the DCDS. 

I am not sure of the location of 19&20  so I pulled the dcds out to see if there are numbers on the reverse side. As I was doing that, the 2 screws that have the grounds where static sparking. I still am not sure the location of 19&20.

The square pin on the board is pin one, and the pins are numbered as follows.

1-3-5-7...

2-4-6-8...

I am getting the 5v from the 19 and 20. But no power to the 10 pin. As a side note, my tmcc functions are unresponsive. All it does is idle and blow off the shut down sounds. no coupler or other RS.

Where was this orange wire that separated from, and where does it go?  G

I am headed out today and hopefully this cheat sheet might help.  Bill or John should be able to help with this.  Please excuse the artwork.

Here are some pictures, flywheel as promised above. I only touched the 5 plugs shown below. That's it, I promise. The orange wire in shown in the last photo in the rear of the 4 prong.  I can take other pictures if it would help. I think we are too deep.

More misc pics

The pics don't really help. I think you should button it up and lets start all over.

Bill

No doubt now it is DCDS. I just swapped one from a working engine.  Can this be fixed or is it dead?

Depends on what happened to it.  If it's one or more of the common parts, yes.  If it's the uP on the board, probably not.

I swapped them back and the thing I did notice is that there is small sparking from the ground on the bad DCDS.  If I drag the ground eyelet on the frame it gives off a small spark. The good one it does not.

Maybe a shorted FET that drives the motor.  Do you have a meter that can do diode checks?  G

yes, what is a FET?

 That is why I asked about the fire box flicker. The DCDS supply the power for flicker.

Bill

Field effect transistor.  The 4 large transistors that are attached to the heat sink act like switches to power the motor.  G

The FETs are common parts and pretty easily replaced.  If it's just a FET, it can be repaired.

For $100, I'd take a stab at replacing $5 worth of FETs first.