Older Hornby/Lima locomotives

[SMSchaz]

I am the fitter of the sound.

I have fitted many locos with DCC chips (including split chassis Mainline) and around 30-40 sound locos!

The loco is now back with me!

Lima class 40 fitted with traction tyres so a dearth of pickups (Fitting more would be a nightmare as it has leading bogies) 2 wheels on one side of the motor bogie the other has traction tyres and 2 each side of the trailing bogie.

1. InitialIy before fitting the sound chip I fitted an 8 pin socket for the chip and ran the loco with an 8 pin blank stall current 370 mA.
2. On return of the loco I have run it on my DCC concepts rolling road no problem (with NCE, Sprog3 & Hornby E-link).
3. So far I have had no short circuits!
4. Sound and motor all work perfectly (the wheels are clean the motor has been serviced) so the chip is in perfect condition!
5. When put on track the loco runs (no short circuits) but it is very jerky and the sound cuts out and the loco stops. A touch and the loco starts moving again the sound has to be re initialised. and the same thing keeps happening (?stay alive needed)
6. I just now have to find out if I can fit stay alive to loksound V4.0
7. On return to the shop I warned that the pickups were inadequate and sugested stay alive might be necessary!

Any further comments would be helpful

[Fishmanoz]

Hi chaz, thanks for contributing and let me modify my previous “fitness for purpose” implications based on what you’ve said. We can now understand the stay alive issue having nothing to do with current draw as JB had thought and your stall test confirms TTS can handle the current.

But in a way, you’ve deepened the mystery of JB’s problem - why when in the shop does it work fine and is drawing only reasonable current but on his layout is tripping the controller? I’m stumped.

[96RAF]

The only thing I would add is there is no resistance on a rolling road. I had an old ring-field diesel which ran fine on RR but could not drag its own weight around a track. In the end I re-magged it.

[SMSchaz]

@96RAF

 

 

Why would that turn the sound off?

[Going Spare]

Could the problem be a poor solder connection or a break in the wiring between the bogies, the DCC socket and the motor causing an intermittent problem that might not be evident on the relatively smooth running on a rolling road but manifests itself when on the layout?

[Fishmanoz]

Hi GS, I’m taking chaz at his word here - he says the overload happens “as soon as I try to move it” - so doesn’t sound like an intermittent?

But then, on the Sherlock Holmes’ logic principle, what else might be left?

[96RAF]

@96RAF

Why would that turn the sound off?

 

 

A motor with a weak magnet can pull a lot of current, which could trip the decoder self protection, hence as soon as it tries and fails to move the sound drops out. I have a couple of ring-fields with TTS that are marginal and act like that when they are cold. After a bit of persuasion they run fine after warming up - a bit like my old Ford Zephyr 6.

[Going Spare]

@Fishmanoz

Look back to para 5 on SM's 29 Jan post - "the loco runs but is very jerky"........"a touch and the loco starts moving again".

[SMSchaz]

Problem sorted Now running ok It seems that the Hornby controllers are more sensitive to any short.

As I was running it on the rolling road without rollers under the leading wheels it ran fine on putting rollers under one leading axle the problem re-ocoured, it seems the leading bogie was causing a momentary short as the wheel touched the frame so I made sure both leading wheelsets were fully insulated. Bingo fully functioning loco+sound

As to why this only caused a short circuit on the Hornby Select/Elite I know not.

Will advise if poor runing is persistent then stay alive may be needed!

[Fishmanoz]

Well done for solving it.

@GS, hadn’t picked up the different reporting of the issue between JB (shorts as soon as he tries to move it) and the more intermittent with chaz. But now clear with the reported solution.