Dear Doctor DCC,

[SpaceMouse]

A club member's desiel loco (owner) was equiped by another club member (installer) with a DCC Decoder. The engine ran fine for a while and stopped. Since the installer has been sick, I acted like I knew what I was doing (buttinsky) and told the owner I'd look at it.

So far I have applied DC power to the poles on the motor and it ran. I tested for continuity from the motor poles to the frame and the truck pick-ups and it appears isolated. The decoder connections appear to be solid, in fact more professional than I could do.I didn't test the light.

That only leaves a fried decoder, right? Anything else I should do? Any way to test the solder joints with disconnecting them? They are attatched then sealed with a plastic compound. No copper is exposed.

[NZRMac]

Sounds like a Randy sort of question, but you've done everything that I would have done, so I would say decoder too.

The motor current may be too high for the decoder most can handle 1amp or so, therefore it's fried!!

Ken.

[selector]

Yep, That's Randy. Where IS the Doc, anyway! [^]

[rrinker]

Well, it's a little hard to check firther without a DCC system. I would stick iton the programming track and see if you can read/write CVs. If that worked, I would find out if there is a reset option (such as Digitrax, CV 08 with 08 resets everything to factory defaults) and try that. Sometimes the decoder just gets 'stuck' and needs a reset. Check lights, too. If you cna program it, and the lights work, but it still won't drive the motor, the output stage is probably blown. You can put a meter on the output and see if it changes as you speed up. Check continuity between the rail pickus and the red and black decoder wires (seperately) and make surte there's good contact tot he pickups. Check the continuity fromt he orang and gry decoder terminals out to the motor, make sure those wires are good. Thin wire such as used in the locos and decoder wiring can develop internal breaks that aren't readily noticeable just looking at the wire.
All else fails, completely remove the decoder and connect the red and black to the track and a spare motor to the orange and grey and see if it works then.
Unless this is some older diesel and the decoder is a Z scale type, it's not too likely the motor draws too much current for the decoder.

--Randy

[Anonymous]

I know I'm new at this, but I had problem with my DCC system and after I checked evrything else I found the culprit was dirty tracks and wheels.

[cmrproducts]

I agree with the other posters about checking the programming and the dirty wheels thing.

I have had my share of dead engines! Most of the time it was a programming thing.

And we all know that our computers never have any problems that would ever require reprogramming ;-)

BOB H Clarion, PA