R3327 S15Class '824' DCC Wiring Issue

[Southern Barbarian]

Hi Guys,

I have the above loco, which runs sweetly in analogue. However, have just tried to fit a DCC sound decoder (ESU Lok v.5 with S15 Howes Sound and 28mm dia speaker, the speaker fits nicely as does the MEM socket and decoder in the tender. Unfortunately the loco does not respond at all. Have checked the orientation (orange to 1 or *) and nothing.

Have tested the Sound decoder on another loco and all works fine. Is there an issue with this model and any suggestions on how to resolve?

Thanks

[Going Spare]

You say the loco runs sweetly in analogue: is that both before fitting the decoder and after refitting the blanking plate?

[Fishmanoz]

Have you tried a different decoder known to be good also? There is a possibility of a wiring issue only showing up on DCC.

[Southern Barbarian]

Hi, Yes have re-tried the loco with the blanking plate fitted to the the loco and it runs fine.

[Southern Barbarian]

Hi, Yes tried a different dcc decoder, in this case a Hornby R8115 (un-rebuilt MN) just to check with the same result.

My thoughts are that it is faulty Hornby wiring from the factory. As the Loco although as new, was issued circa 2016 is well out of warranty, Hornby are not likely to want to know and am starting to think that it might need a re-wire.

Does anyone know of anyone who might offer this service?

[ColinB]

I must admit generally a wiring fault blows up the decoder. For a loco to run on DC and not DCC would tend to indicate there is a fault with the wiring to pins 1,4,5 and 8. Usually if it runs on DC and has issues on DCC it tends to indicate pin 1 is connected to either pins 8 or 4. Similarly pin 5 may be connected to pins 8 or 4. As I say usually if this is the case, the decoder gets damaged. Have you checked that when the decoder is fitted into another loco it still runs backwards and forwards? Basically with nothing in the 8 pin decoder socket, there should be no resistance between all pins except pins 1 and 5, which should measure motor impedance (anything up to 100 ohms). The only other issue I have had is if the decoder has not got enough current drive for the motor, but this is a relatively new loco, so that shouldn't be an issue. What you need to do is do the resistance measurement check between pins and then put in a cheap decoder (in case it blows up) to see if it works.

[96RAF]

As stated by Colin you need to go back to basics and check the loco wiring with a meter and by inspection.

First checks are - is the basic wheel to socket and socket to motor wiring Ok. It appears the outer four pins are Ok if the loco runs when a blanking plate is fitted but this discounts any stray shorts across to the other four pins that come into play when a decoder is plugged in.

Systematic metering of continuity pin to pin across the socket as suggested and a close inspection of the socket underside looking for stray wire strands or solder tracking trace to trace is a must.

The R8215 decoder you have tried is not the most reliable decoder but if it works OK in another loco then it is a good indicator.

[Fishmanoz]

Despite the age, I’d contact Hornby as, if it is wiring, it will clearly show as being there from new and they may do something about it for you.

And David, there’s no need to use the blue arrow as part of your reply process, it’s a trap. Just go to the text box at the bottom with the green Post reply, it will be quite clear who you are replying to.