TCS CNGP No "Va", pulsing headlight....

[sizemore]

I've installed a slew of CNGP's in an assortment of LL/Kato/Atlas stuff to finish the remaining brain transplants on the fleet. One loco (LL C424) I completed at the onset, installed great, tested, programmed and retested again successfully. I put it back in storage and recently took it out to get a programming reference for two more C424 installs I needed to complete. It now exhibits a peculiar issue when I attempt to run it. It responds to direction changes as evident by the headlights switching however the loco does not move, and the headlight ominously pulses. I can factory reset the decoder, and it moves about an inch then goes back into its zombie state with the pulsing headlight.

Thinking it was the motor, I pulled the motor and tested it against a 9V battery which checked out OK. I then proceeded yanked the old decoder and installed a new CNGP thinking the one I previously installed was kaput. Again installed great, tested, programmed and retested with success. I started running the loco, I switched direction and it briefly exhibited the "zombie infection".

I have no shorts, no pinched wires. 3 other C424's and all the other CNGP's I've installed do not exhibit the zombie tendencies. I'm leaning towards the motor as the source of the problem. Any ideas?

The S.

[woodone]

Got spare motor? If so unsolder the orange and gray wires from the decoder and hook up spare some wires to the decoder and hook up to the test motor and see if you still have the same problem.

[sizemore]

That's the problem I don't have a spare motor to test. Before I go running down another motor, was hoping to see if anyone else had a similar experience before I throw $$$ at it.

The S.

[woodone]

Then I would hook up the decoder to one of your other C424's motors to see if the problem is still there.
Not too hard to do.   

[sizemore]

Great suggestion that I was considering, I'm trying to leverage others experience/knowledge first. I'd hate to tear down a working piece and through Murphy's Law, end up with two loco's sidelined.

The S.

[R L Smith]

I currently have a C424 in pieces because I pinched a wire and let the smoke out of the CN decoder.  If the SME's here aren't able to offer a solution, I can send you the motor to borrow to try out the decoder.  I'd hate to tear down a perfectly good-running engine if I didn't have to...

PM me anytime.

Ron

[woodone]

No need to tear down the good running unit. Just remove the shell and then swap the orange and gray wires from one to the other.
 

[sizemore]

I currently have a C424 in pieces because I pinched a wire and let the smoke out of the CN decoder.  If the SME's here aren't able to offer a solution, I can send you the motor to borrow to try out the decoder.  I'd hate to tear down a perfectly good-running engine if I didn't have to...

PM me anytime.

Ron

Appreciate it Ron! I was checking out my inventory of spares I had a slew of LL GP18's in the fodder/kitbash bin, acquired when folks were blowing them out at $20 a pop. It appears that the motors are the same so I can use one of those.

I was bit by Murphys Law, the C424 I pulled the shell from is now having an issue, either it needs more solder added to the pads, or a micro-fracture on the bus. Leaning towards the bus issue though, already did the build up of solder on the pads and has a nice snug fit. I might get lucky as I have an extra slave board.

Exactly what I wanted to avoid.

The S.

[woodone]

Well if just taking off the shell caused the loco to quit running I think that this problem would have shown up sooner or latter.
I don't understand the slave board.
Could you explain ? Or is this the rear board that you are referring to.
Most problems I see with the CN or CN-GP decoders is where the motor lead wires are soldered to.
I machine out a fair amount of material on the frames in that area so the wires and solder joints have lots of room for clearance.   
And most time I have to apply solder to both sides of the boards so there is a good snug fit between the decoder boards and the frame slots.