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DCC Disaster.....?

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Patrick Davey

By Patrick Davey
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Patrick Davey Grand Master

Patrick Davey

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So it was DCC day today and it started off well with a chipped A3r showing off a range of impressive lighting effects and sounds.

Then I decided to chip my MM 125 but I placed the loco onto the by now DCC-ed track before fitting the actual chip, there was a buzzing sound and she won't run, on either DCC or DC.  The chip is fine though, worked great in my other 121, No. 132.

I had been aware of the dangers of doing what I describe above, but perhaps the excitement made me fire ahead carelessly.

What have I done........?

 

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Sean Mentor

Sean

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How long did you have the power applied patrick?

did you try to drive on the DC channel of your DCC controller, and what controller is it?

the buzzing sound would be considered "normal" as it is the motor taking the full voltage of your dcc system but not moving until the dc channel lets it move. since the motors arent moving they heat up to dissapate the power and this is why failure is common when people do this as motors overheat easily.

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Tullygrainey Mentor

Tullygrainey

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I need to step in here and take joint responsibility. I was present at the scene of the crime and party to it. I let him do it🙄. Neither of us was concentrating properly - kids in a toyshop syndrome, I'm afraid.

As Patrick says, it was on the DCC powered track for 3 or 4 seconds. It still had its blanking plate in. When we subsequently inserted the chip and tried to initialise it and give it an address, the NCE system couldn't make contact with the chip and generated an error message.That suggests to me that something in the loco's circuitry has been damaged. No obvious visible damage and no smoke or burning smell.

Alan

Edited by Tullygrainey
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Noel Grand Master

Noel

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Only a few seconds should not have damaged the DC motor when fed with DCC AC wave form. I’ve done it a few times myself by accident. Suggest diagnosis steps:

  1. Put 21 pin DC blanking plate back in the loco, disconnect the NCE from the track and try a DC controller to see if the un chipped loco still runs ok on DC.
  2. Assuming it does run, then remove from track, disconnect DC controller, put 21pin decoder in loco, put loco on test track, go into programming mode on NCE Cab. See if decoder manufacturer ID  and model no are displayed. This tells if decoder is responding. If yes give it a DCC address and try it on DCC. 
  3. if it doesn’t run in 1 above it sounds like the motor was damaged by AC current for too long. 
  4. if after step 3 it won’t run on DCC that might be because the address on the decoder is wrong. A decoder reset CV8=8 will reset the decoder back to factory defaults and default address of 3.
  5. caution: with NCE Power cab only put one loco at a time on the track when programming or you risk programming every loco on the layout, and loosing loco addresses already allocated. Only have the one loco to program have only that on the layout.

 

Hopefully it’s not damaged. 

Edited by Noel
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Tullygrainey Mentor

Tullygrainey

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Thanks for this Noel. However,

1.  With the blanking plate in, the loco doesn't run on DC. (We tried it on Patrick's other layout Brookhall Mill which is DC)

2. With the decoder in, the NCE system can't make contact with the decoder. I think this is a electronic problem with the loco's own circuitry rather than a burnt out motor.

We know the decoder is ok because it's now installed and working in another loco.

 

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irishthump Veteran

irishthump

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1 hour ago, Tullygrainey said:

Thanks for this Noel. However,

1.  With the blanking plate in, the loco doesn't run on DC. (We tried it on Patrick's other layout Brookhall Mill which is DC)

2. With the decoder in, the NCE system can't make contact with the decoder. I think this is a electronic problem with the loco's own circuitry rather than a burnt out motor.

We know the decoder is ok because it's now installed and working in another loco.

 

My ears are burning......😀

It sounds like something in the PCB has gone kaput. The fact that you can't get the decoder to make contact with your controller would support that. If it was the motor you would still be able to communicate with the decoder be able to turn the lights on and off.  You can doublecheck the motor is ok by removing the shell and applying current directly to the motor contacts, if you can get at them. Long time since I took the shell off a 121 so I can't really remember the layout.  

4 hours ago, Georgeconna said:

The DC channel I think is number 0. Not a DC controller.

 

Your saying it aint moving under DC either so something has gone kaput, either the motor or PCB, any Smell of Burn off it when you take the bonnet off?

 

Yeah I'd strongly advise to not use the "DC option" that some DCC controllers have. It works by "stretching" the AC waveform of the DCC signal so it is not true DCC. It can fry motors very, very quickly. Older motors like the Lima and Hornby pancake and ringfield motors can go bang in the blink of an eye. Some modern motors can also be susceptible to damgage.

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Signal Post Collaborator

Signal Post

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One other thing that you may wish to try is (with the blanking plate installed) place it on a DC layout (or rolling road) and bring up the power whilst checking the directional lights on the loco, they should be illuminated at a reasonably high power setting even if the motor has burned out, if they are not showing then the problem is likely to be in the circuitry or wiring of the loco (as @irishthump has mentioned above).

Might also be worth trying the blank plate from your other 121 (No. 132), this would rule damage to the original blank plate (which I understand was installed at the time of the incident) from being the problem, it's unlikely that it is a blank plate problem but for the sake of a few minutes work might be worth checking.

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Patrick Davey Grand Master

Patrick Davey

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Good morning folks, I am very pleased to report that all is now well!  I was going to try some of the diagnostic suggestions which were kindly provided here, so I opened up the access hatch on top of the locomotive and noticed that the blanking plate was very loose, which probably explains why it wasn’t running, anyway it is now running perfectly on both DC and now DCC, with all lighting and sound functions working!!

I feel quite silly for wasting your time…..

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DJ Dangerous Grand Master

DJ Dangerous

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23 minutes ago, Patrick Davey said:

Good morning folks, I am very pleased to report that all is now well!  I was going to try some of the diagnostic suggestions which were kindly provided here, so I opened up the access hatch on top of the locomotive and noticed that the blanking plate was very loose, which probably explains why it wasn’t running, anyway it is now running perfectly on both DC and now DCC, with all lighting and sound functions working!!

I feel quite silly for wasting your time…..

So @Tullygrainey was on the money about the motor!

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Flying Snail Mentor

Flying Snail

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40 minutes ago, Patrick Davey said:

I feel quite silly for wasting your time…..

Don't, we all been there - banging our head against a brick wall trying to solve something that's turned out to be relatively simple in the end.

If it wasn't for your question, the rest of us wouldn't have gotten such a great list of things to check for when something like that inevitably happens to someone else in future

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