Decoder problem

[Alan564017]

I recently purchased an MM 071 Grey along with the MM decoder. I ran on the 071 on a DC track to run it in, preformed perfectly. I then fitted the decoded, put it on a program track, gave it an address (hornby elite) and then put it on the main track. As soon as the wheels touched the track, the cab lights at both ends lit up and it would not move. I addressed it a few times same thing happened, the decoder got a bit hot and began to smell.

 

I took the MM decoder out of the grey and replaced it with a bachmann 4 function decoder from another 071 I have. I didnt give it a new address, the grey ran perfectly, however none of the functions for the running lights would work.

 

To save me a trip to Dublin, does anybody have any ideas as to what the problem maybe and any possible solutions. I suspect that it maybe more than the decoder as the running lights wouldnt work with the bachmann decoder. Help!!

[Noel]

Doesn't sound great especially if you could smell the decoder overheating. Unfortunately I suspect the decoder is fried. You need to establish why. Is there a short in the loco PCB, or was it a fault on the decoder, or however unlikely a problem with the DCC controller. If possible I'd bring the loco and decoder to the dealer who supplied both, and get them to diagnose the cause. Avoids the risk of damage to other components when iteratively swapping out elements when attempting to trace the fault.

 

Ps: I have also test ran 071 locos with a Bachman 4 function decoder but I can't remember if it ran the running lights F0 or not. I don't think it would run the spot light as it is on F4 which those decoders don't have.

Edited April 22, 2015 by Noel

[Alan564017]

Thanks for the reply Noel, the DCC controller is fine, all other locos preforming, looks like a visit to Hawkins Street tomorrow so !!

[Noel]

Thanks for the reply Noel, the DCC controller is fine, all other locos preforming, looks like a visit to Hawkins Street tomorrow so !!

 

The Rathcoole premises may also be an option if its easier for you to get to by road. Might be worth a phone call if it was, to check they can look it there as well as Hawkins street.

[Geoff Johnston]

Hi Alan, I had the same problem with one of the grey locos myself.Got it at Bangor show, took it home ran it in, Fitted decoder and nothing..! LUCK mine didnt fry... I popped in another decoder and of she went......

[Alan564017]

Noel, I forgot to say, I have a 4 function decoder in an orange 071, all the external lights work bot directions, with the exception of the cab lights, I think a 6 function decoder is required for that.

[Alan564017]

Geoff, which type of decoder did you initially use, and which one got it working?

[Noel]

Noel, I forgot to say, I have a 4 function decoder in an orange 071, all the external lights work bot directions, with the exception of the cab lights, I think a 6 function decoder is required for that.

 

OK, so none of the lights worked on your grey 071 with a similar decoder? The first MM sound decoder I bought was DOA (dead on arrival), no drive, no lights, no sound, but the dealer replaced it no problem and it ran fine. FYI, I use Lenz (10321) 4 function decoders on my non-sound 071s because I don't care for the cab lights and they are good value at €25 in Germany for a top brand decoder.

[Alan564017]

Noel, thats correct, I took the bachmann 4 function from an orange 071 and put it in the grey, it ran (very well), but no external lights. When I put the MM decoder in the grey, the instant the wheels touched the track BOTH front and back cab lights came on without function request from the controller, but no movement. As the external lights in the grey didnt work with the bachmann decoder, me thinks it might be more than the MM decoder thats in trouble.

[Geoff Johnston]

Alan ..I had the same problem as you.. when the loco wouldnt run the lights flickered on and off both red and white. I was using a bachmann 21 pin decoder which was new from Hattons..I took it out and replaced it with another used 21 pin bachmann reprogrammed it and of the loco went,, I still have a problem with the lights only one side is working... havn,t sorted that out yet...........

[Noel]

Noel, thats correct, I took the bachmann 4 function from an orange 071 and put it in the grey, it ran (very well), but no external lights. When I put the MM decoder in the grey, the instant the wheels touched the track BOTH front and back cab lights came on without function request from the controller, but no movement. As the external lights in the grey didnt work with the bachmann decoder, me thinks it might be more than the MM decoder thats in trouble.

 

Sounds like there could be an issue with the loco alright.

[irishthump]

It could be the circuit board in the loco causing a short that fried the decoder. The fact that you were able to programme an address to the decoder in the first place would indicate that the decoder was ok to begin with.

[Riversuir226]

Check the wiring as well especially on 071,s as the wires can get caught when putting the hood back on.

[WT CLASS 2-6-4T No. 4]

I was speaking to a guy on the RPSI diesel tour yesterday and he told me that he had similar problems with two MM071's, cab lights on both ends and nothing else, one was a grey model the other a silver and black one. He brought them back to the retailed and received replacements. He was told that the problem was a wire down in the body which was hard to reach that had shorted.