DCC J50 not running

[keith-1202807]

I have a dcc j50 that is about 18 months old, it ran fine in the past but now it runs for 4 secs then stops, then starts again then stops etc, I have changed the 8 pin chip for a new one and it does the same, anyone any ideas what it can be? can it be repaired?

[Chrissaf]

ColinB's reply from your other thread [now removed] reproduced below. Note to ColinB, had to do it this way as the new forum does not have a 'move' an individual reply option.

The favourite has got to be the capacitor across the motor, from what you have said you have replaced the decoder so it is not that. You can remove the capacitor anyway it does nothing on DCC. If that doesn't work then the only other thing is the motor, so to test that take out the decoder and replace it with an 8 pin DC header, now run the loco on DC (NOT DCC IT WILL DAMAGE THE MOTOR). The other thing to check is the 8 pin socket, check that it grips the decoder properly, I have had ones where one of the pins doesn't connect properly, the loco goes over a point which gives it a slight jolt and the decoder loses its connection. I hope that helps.

[Flashbang]

In addition I would also carry out the following... Clean all wheel rims. Clean rear of wheels where the wipers rub. Ensure the wipers remain in light but continual contact with the wheels when the wheel se of an axle is moved side to side.

Look for possible loose wires where they are attached to the motor and any PCB or the decoder socket.

Finally ensure all rail tops are spotlessly clean too. Use a track rubber and if possible follow up with wipe over using a lint free cloth dampened with a little Isopropanol Alcohol (known as IPA) of the 99.9% type.