Two loco decoders failed at once

[Michael_A]

Is this a coincidence? I seem to have two locos that wont work on DCC (both work on DC) that worked perfectly when I last tried them!

All my other locos work, I just cant read or write the loco address to these two, and they wont respond to the previous address code I gave them. I have even tried connecting straight to the pick ups to eliminate dirty wheel / track syndrome.

Do I just bite the bullet and replace the decoders?

[Graskie]

Have they definitely got DCC decoders in them or are they perhaps just DC or DCC ready? Have you tried running them on factory default ID of 03? Have you checked inside them? What system are you using anyway? You've probably said elsewhere but I don't want to trawl through the forum to find that.

[poliss]

Have you tried resetting the decoders?

[Fishmanoz]

When you say they work on DC, do you mean with the decoders fitted or did you remove the decoders to try that?

I wouldn't give up yet. Can you try swapping the decoder between one of the ones that doesn't work into one of the locos that does. Does the fault follow the decoder or does it stay with the loco?

[Michael_A]

Definitely both got decoders in! (They have worked perfectly up to about 6 months ago, then they were simply not used for a while. One was addressed at 81, the other at 40)

If I run them with the track fed from a standard Hornby HM2000 DC controller they both run smoothly and perfectly. (With the decoders left in situ, no change at all to the wiring etc)

I tried 03, no joy. When I try to reprogramme them I get the little buzz you often here, and the twitch of the wheels as well, but then they refuse to operate using the address programmed. As I said, I even programmed them with croc leads directly to the pick ups as I am well aware of the dirty track / wheel issues.

I havent tried resetting. Can someone remind me how to do that?

Thanks all for the replies.

Mike

[Michael_A]

Found the answer right here in the forums. 8 to CV8.............

[Graskie]

So, as suggested by poliss, you have reset both decoders and can now communicate with them and run your 2 locos on DCC? If so, that's great. Can you now read and write CVs? I assume you can. What about DC running? Have you disabled that? If not, it's advisable to do so, and you will find references to doing that on this forum or in instructions.

[Michael_A]

No I found the answer on how to reset the decoder. All of the above is what is happening with the locos, I still cannot control them with DCC

I will try resetting the decoders tomorrow.

[Fishmanoz]

Interesting Catch 22 here - if you can't read or write to the decoder, you can't reset it because reset is a write operation. 

Basically, if you can't write to these decoders, 8 to 8 or anything else, then you won't be able to get them to work. I would try again to write a new different loco ID to them (the different is important). And my last ditch here would still be to swap one of the decoders into a loco that is working on DCC and see if it now fails. 

[poliss]

I shouldn't think that would be a problem Fishy. Remember that when you're programming a loco with a new address you must only have that loco on the track because all locos would be programmed with that address. You only need to know the locos current address for carrying out certain specific operations, and as I remember, resetting a decoder isn't one of them.

The fact that the locos work on DC suggests to me that the decoders are ok, but have just forgotten their addresses.

[Graskie]

Exactly what control system are you using, Michael? Select, Elite or eLink?

[Fishmanoz]

Poliss, you may be right. He does say he cannot read or write loco ID, I thought he said that more generally. 

Michael, you were asked if they worked on the default ID of 003 but I can't see your answering that anywhere. Not unheard of for decoders to go back to this after a short on the layout or otherwise. So worth trying. Reset will put the decoders to this address too. 

And there have also been reported instances where locos will not work again on an address they were set to, so if problem persists, try changing to a completely new address. 

[Michael_A]

The outcome:

The one bought as a DCC fitted loco, worked when I took the body off! Turned out to be a dry joint on the wire soldered to the pickup. Thanks Hornby! (Interestingly the standard Hornby decoder had been wired to a 4 pin plug, and a socket wired into the loco. Not seen that before)

The other loco, decoder failed due to failure of insulation between the motor connection and the pickup. I should have done before what I have now done, cut off the tab that goes under the motor (was the original bottom motor connection) rather than rely on insulation.

What I still dont understand is why both these locos ran perfectly well on DC. Maybe the dry joint one was a coincidence, the other, I guess a short in the faulty decoder.

Eee this DCC stuff can make yer 'ead 'urt at times!

 

[smooth operator]

Interesting problem here, I had the same senario with an 8f. Put away working fine, fetched out probably 12 months later and it would not work. After many a while of dismntling, cleaning etc etc, it finally dawned on me that I had been double heading with this loco and another. (dont ask which one, 'cos I ve not found it yet!). So the consist was a differant address to  the normal running number. I write the addresses and any consists that are in my fleet so I can soon refer to them if I forget. (very often). For what it is worth, may be this will help. 

[Fishmanoz]

You'll find a lot of Hornby DCC fitted use the 4-pin connection type, all that's needed to run the motor but no function outputs easily accessed for use with lights etc. some tell me this is an 8249 but, if it is, it is a different implementation as the board layout is different. 

[Michael_A]

The one in mine iss the old R8215 wired to a 4 pin connector.  I think with th econnector it is sold as X9659.