# Spectrum SD40PH DCC/Sound trouble shooting



## Artieiii (Apr 25, 2011)

I finished my Bachmann Spectrum SD40PH DCC/Sound with Digitrax SDH164D install, but now i am in the trouble shooting stages. At first I was having trouble with some abnormal mechanical sounds.....found some wires that were touching the flywheel when the shell was installed...fixed that. Now I can get it to run properly if I turn the lights out on the engine and put the sound in silent mode. When I run with lights alone (no sound the engine starts to roll for a bit then the decoder resets) and it tries again...over and over If I run with sound and lights it will reset over and over even more frequently. Every once in a while at full speed it will make it around the track for a few loops then reset. I was thinking it might be from the motor and sound decoder is drawing too much power. Am I on the right track here? would installing a small resistor from the decoder to the motor solve the problem? Remember this engine is not DCC ready and it is quite fast. And yes I did clean the tracks plus my other loco's run well. Thanks in advance. Forgot to mention I am using NCE power cab with no other loco's on the track.
-Art


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## NIMT (Jan 6, 2011)

Art,
Sounds like you have dirty wheels or dirty/bad pickups.
If the wheels are clean then I would look at a intermitent short or a open.
No resistor is required on the motor.


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## gc53dfgc (Apr 13, 2010)

Sounds like it would have to be not enough Amps of power (how many does your system offer?) It sound like it could also be a bad decoder, not sure but I fried one and the thing would run at full speed then stop and stutter then go at full speed again. If you still have full control over everything which it sounds like you do you might want to do the factory reset of all CVs and see if that fixs it, otherwise the decoder is shot and you will have to send it to Digitrax and have them ship out a new one which will only cost the price of shipping.


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## Artieiii (Apr 25, 2011)

*Problem solved*



gc53dfgc said:


> Sounds like it would have to be not enough Amps of power (how many does your system offer?) It sound like it could also be a bad decoder, not sure but I fried one and the thing would run at full speed then stop and stutter then go at full speed again. If you still have full control over everything which it sounds like you do you might want to do the factory reset of all CVs and see if that fixs it, otherwise the decoder is shot and you will have to send it to Digitrax and have them ship out a new one which will only cost the price of shipping.


I was getting frustrated, started disassembly to try to clean the contacts as I unwrapped the wires I discovered one of the 2 wires on the capacitor must have gotten pulled off. Dumb mistake. Now that I figured it out, it all makes sense. Cleaning the track helped a bit but no cure. No capacitor, any little poor track contact and the decoder has to restart. Whew that was a close one. Thanks for your suggestions all. Now it runs and sounds good :thumbsup::thumbsup:
-Art


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