TCS CN-GP Troubleshooting

[nickelplate759]

I just installed a TCS CN-GP in an old Atlas TT GP-9.  It went in fine, but when I put it on the track it takes off at full speed, totally ignoring both the throttle setting (0) and the DCC Engine number.   It's as if it's just seeing high voltage DCC and off it goes.

It's going "backward" by the way, and the appropriate light (rear) is on.

I've double checked my wiring - orange to the bottom of the motor, grey to the top.  Both boards installed with the LED side up, and the wires (Yellow Black, Blue) matching at each end per the directions.

It's a puzzlement.  Any ideas?

[Jim Starbuck]

Try turning off analog DC function.
As far as the backwards part. The direction of travel can easily be changed in the programming. The documentation with the decoder will tell you how to set it up. I think it’s part of CV 29.

Hope this helps
Jim

[nickelplate759]

Problem solved - it was the same as this problem:

https://www.therailwire.net/forum/index.php?topic=44838.msg577982#msg577982


The rear board wasn't making  good contact. Adding solder to the contact pads fixed it.  I've no idea why poor contact on the rear board makes the engine go full speed in reverse...

[nickelplate759]

By the way, I've found that cutting the length of the gray and orange wires just right on the CN-GP is a very fiddly process that I'm bad at.  I've found a way that's easier for me.
1.  Remove (unsolder) the gray and orange wires from the control board (front board).  Leave them full length!  Remember which one went where - you'll be putting them back later.
2.  Strip one and tin end of the orange wire and solder to the lower brush contact (NOT the cap) of the motor.
3.  Strip one and tin end of the gray wire and solder to the upper brush contact (NOT the cap) of the motor.
4.  Reassemble the frame.
5.  Install the front control board (adding solder to the frame contact pads if desired).
7.  NOW measure the gray wire, cut and tin, and solder to the "gray" pad on front control board.
8.  Measure, cut, tin and solder the orange wire to the "orange" pad on the front control board.
9.  Install the rear board (after adding solder to the frame contact pads).
10. Measure, cut, tin and solder the yellow, black and blue wires to the rear board.

[central.vermont]

George,
I do the same thing. Only thing I do differently is when I cut the orange and gray wires I leave just a little bit of the wire insulation to tell which is which.
Jon

[jagged ben]

Thanks for pointing me to that old thread.  I have a couple of these that sometimes act up intermittently.   Now I have something to check for