Model train DC to DCC problem
Discussion
I converted a Hornby J94 a few days back to DCC using a zimo budget decoder (first attempt so was keeping it cheap)
When testing it it would start and then stop, then maybe start again and stop again. I tested the volts across the motor and when it was stopping it had no volts hitting the motor (so makes sense it would stop).
I then checked the voltage across the pickup wires connected to the decoder, they were dropping to zero also at the time it stopped.
I then checked at the wheels itself (not the pickups) and they would drop to zero when it stopped also.
So I put the loco on a rolling road and checked the voltage and the track was constantly sending current to the loco wheels, so system is not shutting down and send isolated to the loco.
I have cleaned the wheels and it didn't make a difference, so wondering if it is the pickup or this is something that is set wrong in the decoder?
Also if the decoder had some cut off or something would that affect any of the pickup circuitry (ie the wires or at the wheels)?
The other factory fitted DCC locos run fine and I have resoldered all connections in case it was that. Any ideas?
When testing it it would start and then stop, then maybe start again and stop again. I tested the volts across the motor and when it was stopping it had no volts hitting the motor (so makes sense it would stop).
I then checked the voltage across the pickup wires connected to the decoder, they were dropping to zero also at the time it stopped.
I then checked at the wheels itself (not the pickups) and they would drop to zero when it stopped also.
So I put the loco on a rolling road and checked the voltage and the track was constantly sending current to the loco wheels, so system is not shutting down and send isolated to the loco.
I have cleaned the wheels and it didn't make a difference, so wondering if it is the pickup or this is something that is set wrong in the decoder?
Also if the decoder had some cut off or something would that affect any of the pickup circuitry (ie the wires or at the wheels)?
The other factory fitted DCC locos run fine and I have resoldered all connections in case it was that. Any ideas?
My understanding is (I haven't used DCC at all so it's just based on what I've read) that with DCC the track is live all the time so for you to get 0 volts at the wheels means that there is something wrong in the way the wheel is picking up the current.
Either that or is something shorting out between the wheels and the chassis on the loco as the wheels turn (connecting rod or something) therefore tripping the DCC controller momentarily?
Either that or is something shorting out between the wheels and the chassis on the loco as the wheels turn (connecting rod or something) therefore tripping the DCC controller momentarily?
spitfire-ian said:
My understanding is (I haven't used DCC at all so it's just based on what I've read) that with DCC the track is live all the time so for you to get 0 volts at the wheels means that there is something wrong in the way the wheel is picking up the current.
Either that or is something shorting out between the wheels and the chassis on the loco as the wheels turn (connecting rod or something) therefore tripping the DCC controller momentarily?
I do think it is a short or the pick up, but the track stays constant with DCC current and another train keeps running when I just tested that, while the j94 stops then starts. Either that or is something shorting out between the wheels and the chassis on the loco as the wheels turn (connecting rod or something) therefore tripping the DCC controller momentarily?
I just don't get why the wheels would show no DCC voltage... If it was pickup from the wheels then they would be still showing the volts.
So has to be the wheels not picking off the track.
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