Burning out DCC decoders

[DevilsAdvocate]

Hi folks,

 

I recently had a mad moment and purchased one of Hornby’s R30231 HM Queen’s platinum Jubilee West Country locomotives  which cost more than I’ve ever paid for a loco in my life, however that serves me right for not pre ordering one and getting one when they were released, however, I have an issue with this loco

 

It runs perfectly in analogue, however, when I add a DCC decoder an put an address to it, it burns out the chip

in the first instance, I put it down to a faulty chip, however, this has now happened 3 times, and I’m not willing to keep burning out decoders, the price they are

 

Clearly, there’s something very wrong here

 

i have contacted Hornby, who quite frankly don’t give a toss, stating they have nothing to do with decoders unless it’s one of their own

For those who aren’t aware, the loco is a 21 pin decoder

Hornby don’t manufacture 21 pin decoders, therefore you have no option but to use one from elsewhere.

For this reason, they aren’t interested

 

I have never known this happen before.

 

What can be causing this. Can anyone assist please ?

 

Cheers

[WIMorrison]

Which decoders have you tried and what was the current rating for them?

[DevilsAdvocate]

Hi Iain

 

All were Bachmann 36-557’s. Ones I’ve always used as they have suited my needs and never let me down previously

As for the current rating, I can’t say I’m sure. This side of the hobby isn’t my strongest point unfortunately 

 

Cheers

[WIMorrison]

Lots of threads here on these decoders and issues that people have had. It is actually a soundtrax mc1 so start with that to find the current rating and see if it is high enough for the loco.

 

general advice is to buy a mainstream decoder from Lenz or Zimo though ;)

[DevilsAdvocate]

Cheers again Iain

 

Your comment makes sense

i have never had to do this in 40 years of modelling, so I wouldn’t, and didn’t think any different 

I hear what your saying, I’m wary of splashing out on yet another decoder until I’ve got to the bottom of this, although as I said above,  your point makes perfect sense

 

is there anyone out there who’s got one of these loco’s and if so which decoder did you use for it ?

 

Thanks again

[RedgateModels]

Was it OK on the programming track? No shorts detected? 

[DevilsAdvocate]

Hi Redgate

 

Yes, programming the loco on the programming track was fine, however when the loco is placed on the layout and power is applied, the decoder starts to burn out

 

Cheers

[dpgibbons]

That decoder is rated at 1A, which ought to be plenty. I suspect that you have a wiring issue.

[DevilsAdvocate]

Hope not dp 

 

I don’t want to involve Hornby for a repair. They are arrogant and patronising, and  I asked for their opinion and they wouldn’t budge from blaming the decoders

They stated that as the loco works perfectly in analogue, it wouldn’t be a fault with the loco

[BMS]

If you have a multimeter then with nothing in the  DCC Ready Socket check that no wheel is connected to the wiring at the motor end. if poss rotate the motor so that this is tested for the full driver rotation.

Also when running on straight DC check that there are no sparks, or odd noises etc - this would show intermittent shorts which would blow the decoder or t least trip it.

(Frankly i have a similar unsolved problem in which the loco works well on dc, the decoder tests out on a decoder tester, no detected shorts and yet the loco doesn't run on dcc and the decoder gets hot. Guess which manufacturer made the loco.😁)

Goof luck!

[DevilsAdvocate]

Hi BMS

 

Thanks for that.

You have easily managed to blind me with technological  science with that. Ha ha

However, there are no signs of anything untoward until power is applied, then enter a smoking decoder and another 30 odd quid down the pipe !

 

I assume you’re talking Hornby

 

You have to laugh really

 

It’s the only loco I’ve known them put a 21 pin socket in, when they don’t manufacture one, so you’ve no option but to put someone else’s in, and then they turn round and state they’re not interested in any DCC faults as you’re not using one of their decoders !

 

I paid £600 for this loco and the people that manufactured it just aren’t interested

 

Cheers once again

 

[jpendle]

28 minutes ago, DevilsAdvocate said:

They stated that as the loco works perfectly in analogue, it wouldn’t be a fault with the loco

Quite frankly that's rubbish.

 

If the loco pcb/wiring has a short from the pickups to the motor terminals then its going to run fine on DC because that's what a blanking plug does.

The decoder won't be happy though.

 

I've a Dapol N Gauge CL156 where the decoder in the dummy car doesn't work and the lights won't come on, works fine on DC and there's nothing wrong with any of the decoders that I've tried.

At least I've not fried any of them as there's no motor.

 

Regards,

 

John P

[DevilsAdvocate]

Hi John P

 

Yep, but that’s what they said, and they wouldn’t budge from it

Thing is, how can I get them to repair it when they won’t accept that the loco could be at fault ??

 

I sent this loco back to them recently, as I noticed a squealing noise from the motor

I sent a decoder with loco and asked them if they would test it in the loco to see what this issue was

They greased and oiled the motor, but wouldn’t entertain the decoder issue

[LMSfan72]

Hornby do manufacture one: https://uk.Hornby.com/products/hm7000-21-bluetoothr-dcc-decoder-21-pin-r7402

 

so, you could purchase one and fit it and when it burns out they can’t complain….

[WIMorrison]

2 minutes ago, LMSfan72 said:

Hornby do manufacture one: https://uk.Hornby.com/products/hm7000-21-bluetoothr-dcc-decoder-21-pin-r7402

 

so, you could purchase one and fit it and when it burns out they can’t complain….

 

Hornby WILL manufacture one, but not yet - check out the release date in your link 🤔

[LMSfan72]

Oh yeah, wrong link: https://uk.Hornby.com/products/hm7000-21txs-ble-decoder-21-pin-txs-sound-r7322?_br_psugg_q=hm7000

 

granted, it’s sound 

[DevilsAdvocate]

Cheers folks

 

I’m torn between leaving it as it is, after all, I bought this as an investment as it will only increase in value, and I have no intention of selling it, however that said I have a DCC layout so it can’t run on it, and I would like it too obviously.

 

Does anyone know of an outlet / modeller etc that would take a look at it for me ?

 

I’m sure this isn’t a massive issue, it’s more a case of someone knowing what they’re looking at (  which isn’t me I can assure you )

it’s pointless keep purchasing different decoders at £30+ a time for them to just keep burning out.

 

Cheers again all

 

 

[WIMorrison]

Question - how do you know they have ‘burned out’? Is it just the motor doesn’t turn or was there magic smoke from the decoder and then it stopped working?

[Ray H]

Is there a possible case under the Sale of Goods Act especially if you could take a decoder, check/prove it is working in a different loco and then show it not working in the loco concerned? Could you find a Hornby dealer who would witness what you find?

 

Might just be worth checking under the socket to make sure that nothing is touching where it shouldn't. Presumably, as it comes with a blanking plate, the socket's wiring only needs to work initially on the pins that (I assume) when connected, link the motor to the pick-ups. If there's a short with any other part of the socket that wouldn't matter under dc operation.

 

Is it possible that you have caused the socket to move just enough when pressing the decoder into the socket that something that shouldn't be touching comes into play?

 

Is the 21 pin decoder a necessity? Could you remove the 21 pin socket and hard wire a decoder with a different type connection like the 8 pin decoders that come with a harness from which you cut off the connector? I assume that you only need the motor and track power pick-up connections - i.e., there aren't any lights and things like that which you want to use, so you wouldn't lose anything using few connections.

 

Do you have anyone near you that could help if you don't feel confident in doing these things yourself?

[DevilsAdvocate]

The decoder starts smoking heavily when power is applied. When the decoder is removed and put into another loco, it’s dead. 
Thanks Ray

A lot of good stuff there. Hard wiring is a good option, never thought of that, however that’s beyond my knowledge unfortunately so I’d need someone to do that for me but it’s a good option 

I live in Derby, and there aren’t sufficient model railway outlets around here nowadays, however I would willingly send it somewhere to someone who knows how to do such things

 

Great feedback from you all though, I’m grateful for it all. 

 

 

[Ray H]

If nobody more local to you offers to help - give them a day or two to catch up - you can PM me and I'll do it for you if you're happy to post it.

[SRman]

12 hours ago, WIMorrison said:

Lots of threads here on these decoders and issues that people have had. It is actually a soundtrax mc1 so start with that to find the current rating and see if it is high enough for the loco.

 

general advice is to buy a mainstream decoder from Lenz or Zimo though ;)

 

It could also be an ESU decoder. Bachmann confusingly changed the spec and supplier but used the same 36-557 catalogue number. The ESU also has a 1 amp rating and should be OK. Easy indicators: green is Soundtraxx, blue is ESU.

DevilsAdvocate, I would remove the decoder (if you haven't already), and check the bases of the pins to see if there are any whiskers of solder bridging the gaps where the pins meet the PCB. If you can, use a sharp knife to cut between each pin at the base to make sure of this. I had a few anomalies once with a Bachmann class 150 with just such a problem. Using the knife solved it completely.

[DevilsAdvocate]

4 hours ago, SRman said:

 

It could also be an ESU decoder. Bachmann confusingly changed the spec and supplier but used the same 36-557 catalogue number. The ESU also has a 1 amp rating and should be OK. Easy indicators: green is Soundtraxx, blue is ESU.

DevilsAdvocate, I would remove the decoder (if you haven't already), and check the bases of the pins to see if there are any whiskers of solder bridging the gaps where the pins meet the PCB. If you can, use a sharp knife to cut between each pin at the base to make sure of this. I had a few anomalies once with a Bachmann class 150 with just such a problem. Using the knife solved it completely.

 

4 hours ago, Ray H said:

you

 

4 hours ago, Ray H said:

If nobody more local to you offers to help - give them a day or two to catch up - you can PM me and I'll do it for you if you're happy to post it.

Nice one Ray. I just may take you up on that. I’m away from home for a week so I will contact you on my return

[peterfgf]

If you have Decoder Pro it ought to identify the decoder (sometimes).

I've stated paying more attention to the specs after burning out a couple of DCC Concepts decoders and then finding there was no overload protection.  There was reason they were cheap.

Peterfgf

[DevilsAdvocate]

Hi Pete

 

Thanks for that. Yes, you have a good point there..The Bachmann decoders I used were spares I had, si I’ve had them a while. I don’t think they make them now, they have switched to Plux 22, although until now, they have suited me fine.

certainly in the future I’ll be buying the more expensive ones as you get what you pay for at the end of the day..

 

For this particular loco I think I’ll have to go down the hard wiring route as Ray has suggested as there is something clearly wrong with the DCC. Side of it

 

Cheers boys