Lenz Silver 21+ Decoder fitted into a Heljan Railbus

[resin001]

I fitted the above 21 pin decoder into my Heljan Railbus today and noticed some strange behaviour

 

I programmed the decoder using decoder pro and verified with my ESU 50200

 

If I run the railbus in a forward direction after a few seconds the loco speed becomes erratic and sometimes even stops and reverses direction !

 

Running in reverse direction shows similar behaviour but not as often.

 

I tried all the usual fixes with no improvement ( decoder reset / disable railcom / disable DC ). The only way to obtain normal running was to set CV29 to reverse direction with the result that the lights no longer work.

 

Suspecting a faulty decoder , I swapped to a " Bachmann " Lokpilot 3.0 taken from their Class 46 Diesel- This resulted in perfect results ( movement and lights )

 

This confirmed , so I thought,  that the Lenz decoder was faulty until I fitted into the Class 46 - This also resulted in perfect results ( movement and lights )

 

Swapping decoders back again resulted in the same initial results

 

Has anyone else had similar problems , know of a fix for the Lenz / Railbus option ? - I would prefer to use the Lenz decoder as the Railbius headlights can be dimmed with this combination

 

Regards

Bob

[34theletterbetweenB&D]

Guess here. Something on the Railbus chassis has activated the decoder's ABC capability. Poor pick up contact, dry soldered joints or clip on wiring, duff suppression capacitor, an assembly error in the lighting control diodes; these are possibles for inducing this.  

 

As always with any decoder malfunction, do a reset. Once back at default address 03, try again on the chassis before any further programming.

[tractor_37260]

Hi Bob

As the decoder works as normal in the other locos, it's possible that the base of the circuit board is shorting on the metal chassis when fitted to the Rail bus. This was a common problem with other Heljan models. Prise the loco circuit board up. so you can get underneath it. Place some insulating tape over any solder points under the decoder socket area etc.  Have you tried any other decoder in the Rail bus apart from the Lenz 21pin ? 

HTH

[resin001]

Hi Bob

As the decoder works as normal in the other locos, it's possible that the base of the circuit board is shorting on the metal chassis when fitted to the Rail bus. This was a common problem with other Heljan models. Prise the loco circuit board up. so you can get underneath it. Place some insulating tape over any solder points under the decoder socket area etc.  Have you tried any other decoder in the Rail bus apart from the Lenz 21pin ? 

HTH

The Heljan circuit board is suspended on the roof of this model and was left unattached from the chassis whilst testing - so doubt a short was occurring. The Lokpilot is the only 21 pin decoder that I have and this does work perfectly indicating no other wiring faults on the model. I wonder if it could be a motor frequency / decoder issue that could be overcome with a CV setting - will read the manual

[johnd]

Had a problem with my Class 28 when i fitted a Bachmann 21 pin 4fct decoder ( 277) in as much as it would not program.  Took the decoder back.

 

A week later bought another of the same decoder, programmed it in a diffrent loco then transfered it to the 128 and since then it has worked ok.

 

Strange going ons. Outcome is I have purchased a Bachmann chassis with a 21 pin socket and will program any decoder before fitting it to its dedicated loco.

[RFS]

I have several Bachmann 4CEPs into which I fitted Lenz 21-pin silver decoders and they all run beautifully. With my first 2EPB I also fitted the Lenz decoder, only to find some erratic running. With my latest layout problems with the 2EPBs (I now had 4) became serious - two still had Lenz but the other two had basic Bachmann 36-554.  The Bachmann-fitted ones ran perfectly but with the annoying habit of the decoders resetting from time to time after a system short.

 

Tried everything I could think of but couldn't get them to work reliably with the Lenz.  At one point I found I could resolve poor running by the simple expedient of placing a lighted Hornby Pullman on the adjacent track.

 

In the end I gave up and all 4 units now run extremely well with Hornby Sapphire decoders. The two Bachmann 36-554 decoders fetched a premium on Ebay compared with the cost from Hatton's.

 

I'm assuming something in the electronic circuitry of the 2EPBs was interfering with the DCC signal.  Given the Kernow Thumpers seem to be based on the 2EPBs I was wondering how they'd cope with the Lenz decoders, being as I had 2 spare!  But they work perfectly so I assume the circuitry is different. 

 

I just wonder whether the Heljan has the same issue with its electronics and the Lenz, as other decoders work OK in it.  Have you tried removing the capacitor(s)?  I didn't do that on my 2EPBs as there appear to be 3 of them, two of which are buried under the motor. Also as the Sapphire worked I had a solution.

[tender]

I think it's something to do with the lighting circuit in recent Bachmann (D)EMU's that the Lenz decoders doesn't like. The Bachmann DLW has a similar problem with the Lenz, the lighting circuit return goes to one of the track pickups. I rewired mine back to the decoder common and the problem went away. I suspect the 2EPBs are the same. The Thumper shouldn't have this problem as there's no lighting.

 

Maybe the RailBus is similarly wired?

[RFS]

I think it's something to do with the lighting circuit in recent Bachmann (D)EMU's that the Lenz decoders doesn't like. The Bachmann DLW has a similar problem with the Lenz, the lighting circuit return goes to one of the track pickups. I rewired mine back to the decoder common and the problem went away. I suspect the 2EPBs are the same. The Thumper shouldn't have this problem as there's no lighting.

 

Maybe the RailBus is similarly wired?

The Thumper has the same lighting as the 2EPB, except that there are switches underneath each coach to allow you to turn off either the interior lighting or the headcodes. Perhaps in this case it's been wired properly (ie back to the decoder). The 4CEPs do not have this problem and mine run perfectly with Lenz decoders.

[Adrian Wintle]

 Perhaps in this case it's been wired properly (ie back to the decoder). The 4CEPs do not have this problem and mine run perfectly with Lenz decoders.

 

Either scheme - common return to blue wire or return to a track feed - is acceptable for DCC and should be properly supported by a decoder. Six-pin decoders depend on the return to a track feed as they don't have a function return.

 

Adrian

[tender]

The Thumper has the same lighting as the 2EPB, except that there are switches underneath each coach to allow you to turn off either the interior lighting or the headcodes. Perhaps in this case it's been wired properly (ie back to the decoder). The 4CEPs do not have this problem and mine run perfectly with Lenz decoders.

Oops, Thanks for pointing out my mistake RFS, of course it's the 2BIls that have no interior lighting.

 

I'm now using Zimo decoders which don't seem to have this problem.

[SRman]

I have fitted Lenz silver decoders into four out of my five Bachmann 4 CEP unts and all five 2 EPB units with no probems at all. The fifth CEP unit has an ESU LokSound decoder which runs nicely with the Lenz-fitted units.

 

I have heard of the lighting circuits interfering on some models, as others have mentioned earlier in this topic. 

 

The other thing that occurs to me is that the cpacitors may be interfering - I usually remove any capacitors I can find on Bachmann locos and on at least some of my Heljan locos. I usually prefer ESU LokPilots on my non-sound-fitted Heljan locos, though.

[alangr]

I have just come across this thread and can say that I have had just the same problems as esin001.  In the end I had to change both the Heljan railcar and the decoder (i.e. get replacements for each) to get matters working as they should - see "Heljan Railbus - DCC problems with handheld and RR&Co" for more details.

 

Cheers