Hornby Class 20 Not running on DCC or DC

[Allen-356998]

Hello Forum

I bought a second-hand Hornby Class 20 (R2761) which is DCC chipped, someone fitted one in it since. However it does not run either on DCC (and I have tried all the factory resets and 3, 03 etc) but it also does not run on DC. Should I assume it a) needs a "blank" chip put in to replace the DCC chip which might be blown? or b) that the engine's blown? The wiring all seems firm and connected and the wheels clean.

I don't know the history of the loco but when programming and it sat on the track there is very faint humming from the chip (not engine). And when programming it is possible to hear the chip pulsing when receiving an instruction from the digital controller. But there is no life at all in the engine, no hum, nothing. I am assuming it is getting electrical pickup from the tracks because the chip hums. But as I say, on digital or DC setup (I have both) the loco is non responsive.

My other DCC trains work fine on my digital track (they also work well running on analogue) as do other DC trains work fine on the DC track. It's just this loco that's dead. Being that there's no life from the engine, should I replace that or go with the "blank" chip (X9084) to I guess return it to analogue?

I don't actually use a digital layout, I prefer them on analogue so "blank" chipping is fine for me, I would just like it to run. DCC is not really my expertise, so any advice is most welcome.

Kind thanks,

Allen

[96RAF]

Fit a blanking plate and run basic fault finding checks with a multimeter.

Typical blanking plates.

[Fishmanoz]

Are you certain it has a decoder fitted, not a blanking plug?

What you are describing on the programming track would be consistent with a blanking plug fitted and the motor humming when programming commands sent. On the main track, it would hum all the time and be at risk of burning out the motor.

If it does have a decoder fitted, it may not run on DC depending on CV29 setting. Test with blanking plug as RAF suggests.

[Allen-356998]

Many thanks for the advice.

The blank chip arrive today and with that in the loco works as it should.

Out of interest, this is the original DCC chip that was causing the problem. Do you happen to know what the extra part of it is; is it a sound card?

Many thanks,

Allen

[96RAF]

It is a sound decoder and the bit to the right of photo is an iPhone type speaker often used to improve the sound.

To determine the decoder you would need to interrogate CVs 7 and 8 using a DCC controller that can read back on a programming track.

[ColinB]

What I normally try to do if I think the decoder is broken, is put it on a programming track and see if I can read a manufacturer id. I can't remember which CV number it is but I am sure you can find out (I have an Elite which just reads it without knowing the CV number). Sometimes if the decoder has Keep Alive/Stay Alive fitted then this does not work. I suppose the other thing to check is that there are no broken wires or pins on the decoder header. Yes it is a sound card with an iphone speaker, probably a TTS one as it has black heatshrink over it, LokSound and Zimo tend to use clear heatshrink but I could be wrong. Carefully snip off the heatshrink and you will see more and possibly if any wires have fell off.