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Discussion Starter · #1 ·
Hi folks,

One of my locos has developed a strange problem that has left me puzzled. The loco (Arnold SBB RE4/4ii) was running OK but the lights at one end weren't working so checked all the settings and everything fine so decided to check the bulbs. Having removed the body once I put it back on the track it immediately started lurching about an inch along the track at about half second intervals - a bit like some locos do on a programming track as it goes through programming. The speed was set at zero and it did this irrespective of any loco selected on the hand controller.

I have checked it out on the programming track and everything appears fine there - address etc. Tried a full reset which it took and it did the same on address 3 and then reprogrammed the address (to prove the decoder was OK) but it still keeps on lurching away whenever I put it on the main track! It has a TCS M1 fitted but I suspect that isn't the problem. All the wiring looks fine so I'm stumped. Any clues as to the problem and how to fix it?
 

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QUOTE (Geoff Booth @ 20 Jul 2008, 20:52) <{POST_SNAPBACK}>Hi folks,

One of my locos has developed a strange problem that has left me puzzled. The loco (Arnold SBB RE4/4ii) was running OK but the lights at one end weren't working so checked all the settings and everything fine so decided to check the bulbs. Having removed the body once I put it back on the track it immediately started lurching about an inch along the track at about half second intervals - a bit like some locos do on a programming track as it goes through programming. The speed was set at zero and it did this irrespective of any loco selected on the hand controller.

I have checked it out on the programming track and everything appears fine there - address etc. Tried a full reset which it took and it did the same on address 3 and then reprogrammed the address (to prove the decoder was OK) but it still keeps on lurching away whenever I put it on the main track! It has a TCS M1 fitted but I suspect that isn't the problem. All the wiring looks fine so I'm stumped. Any clues as to the problem and how to fix it?


Hi Geoff.
I don't know this loco but it sounds like perhaps you upset something on the chassis. Did you do anything to the quartering of the wheels or upset the valve gear in any way.Sometimes sticking valve gear will give this type of problem. Carefully examine the loco to make sure that nothing has got bent out of shape in any way.Its very easy to do. I know because I have done it myself.first off try the loco on the track without the body. Putting the body back may have put pressure on something.
 

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Discussion Starter · #3 ·
QUOTE (TonyDaly @ 20 Jul 2008, 22:00) <{POST_SNAPBACK}>Hi Geoff.
I don't know this loco but it sounds like perhaps you upset something on the chassis. Did you do anything to the quartering of the wheels or upset the valve gear in any way.Sometimes sticking valve gear will give this type of problem. Carefully examine the loco to make sure that nothing has got bent out of shape in any way.Its very easy to do. I know because I have done it myself.first off try the loco on the track without the body. Putting the body back may have put pressure on something.

Hi Tony,

I will give it another check over but haven't put the body back on as this started once the body was off; that came off routinely without any problems.

Regards

Geoff
 

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QUOTE (Geoff Booth @ 21 Jul 2008, 06:41) <{POST_SNAPBACK}>Hi Tony,

I will give it another check over but haven't put the body back on as this started once the body was off; that came off routinely without any problems.

Regards

Geoff

Hello Geoff

Reset decoder set CV30 to 2

Check that both the decoder and the controller are set to 28/128 speed steps. The light problem + lurching can often be related to a mismatch of speed steps - usually the controller has accidentally been changed to 14 steps when this happens, but it can be decoder side too....

also check:

100% of suppression parts (capacitors and chokes) are removed.

Reset decoder CV30 to 2

re-check and let us know

regards

Richard
 

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Afternoon,Richard, I just noticed that you recommend not only removing capacitors but chokes ( what I called inductors) as well.
After my recent experiences with NCE decoders, I must agree - I had upto now only removed capacitors but will be getting rid of the chokes as well.
 

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QUOTE (Sol @ 21 Jul 2008, 14:59) <{POST_SNAPBACK}>Afternoon,Richard, I just noticed that you recommend not only removing capacitors but chokes ( what I called inductors) as well.
After my recent experiences with NCE decoders, I must agree - I had upto now only removed capacitors but will be getting rid of the chokes as well.

Hi Sol

Yes, I used to simply remove caps but recently Bachmann add so many odd bits including more than one capacitor - sometimes with them hidden under the motor, that I now just remove everything from the brushes and hard wire almost all loco's... its worth it to not hit the odd problem loco, and I can always guarantee a perfect runner for my customers - and myself too!

Interesting that in an experiment recently, Martin71 tested with an without suppression/caps for both ESU and TCS, and found the effect on the ESU was much greater than on the TCS.... I'd have expected different, but its yet another reason to avoid them!

Not easy for many modellers with increasing use of surface mount components though

Richard
DCCconcepts
 

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Discussion Starter · #7 ·
QUOTE (Richard Johnson @ 21 Jul 2008, 05:02) <{POST_SNAPBACK}>Hello Geoff

Reset decoder set CV30 to 2

Check that both the decoder and the controller are set to 28/128 speed steps. The light problem + lurching can often be related to a mismatch of speed steps - usually the controller has accidentally been changed to 14 steps when this happens, but it can be decoder side too....

also check:

100% of suppression parts (capacitors and chokes) are removed.

Reset decoder CV30 to 2

re-check and let us know

regards

Richard

Hi Richard

Done another reset, problem remains. Checked that the speed step is at 28 on CV29 and the hand controller shows a max of 28 so that appears to match. No suppression parts on the circuit board, they have been removed.

I got it to stop doing this at one point when one of the bulbs was shifted in its housing but the underlying problem remains. BTW I am using a LZV100 and LH100 both version 3.6.

Regards

Geoff
 

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QUOTE (Geoff Booth @ 21 Jul 2008, 16:00) <{POST_SNAPBACK}>Hi Richard

Done another reset, problem remains. Checked that the speed step is at 28 on CV29 and the hand controller shows a max of 28 so that appears to match. No suppression parts on the circuit board, they have been removed.

I got it to stop doing this at one point when one of the bulbs was shifted in its housing but the underlying problem remains. BTW I am using a LZV100 and LH100 both version 3.6.

Regards

Geoff

Hi Geoff

Hmmm.

If its only 1 loco then I really don't think is a command station issue.

OK... I'm presuming being N scale the bulbs are using white/yellow but no blue wire/grounding thru the chassis. I have no easy answer so lets eliminate what we can....

As an experiment, take out both bulbs.... does this fix it running-wise?

If it does then it may be a bulb with a semi faulty filament creating an occasional intermittent resistance from rail voltage to fuction wire - that'll be a "back door" into the decoder as the Fn wire is after all rectification - so if its broken away and contacting occasionally it will be creating all sort of interesting interference as its impedance rapidly changes as it heats/cools and lets go with vibration/movement.

Either way, bulbs can bea nuisance later on so I'd replace both with LEDs using both blue and function wire if U have wiring room.... if not, use white LEDs via function wire with the + leads to chassis and 500ohm to 1k resistors.

There's not much else it can be if the wiring is right....

** recheck wiring just in case for the tiniest strand of copper can create havoc.
** motor - but thats very very unlikely as the symptoms aren't right
**mechanism - ditto - doesn't match symptoms

So

If its not fixed by removing the bulbs it may well be a decoder fault.... try another perhaps

fingers crossed

Richard
 

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Discussion Starter · #9 ·
QUOTE (Richard Johnson @ 21 Jul 2008, 09:35) <{POST_SNAPBACK}>Hi Geoff

Hmmm.

If its only 1 loco then I really don't think is a command station issue.

OK... I'm presuming being N scale the bulbs are using white/yellow but no blue wire/grounding thru the chassis. I have no easy answer so lets eliminate what we can....

As an experiment, take out both bulbs.... does this fix it running-wise?

If it does then it may be a bulb with a semi faulty filament creating an occasional intermittent resistance from rail voltage to fuction wire - that'll be a "back door" into the decoder as the Fn wire is after all rectification - so if its broken away and contacting occasionally it will be creating all sort of interesting interference as its impedance rapidly changes as it heats/cools and lets go with vibration/movement.

Either way, bulbs can bea nuisance later on so I'd replace both with LEDs using both blue and function wire if U have wiring room.... if not, use white LEDs via function wire with the + leads to chassis and 500ohm to 1k resistors.

There's not much else it can be if the wiring is right....

** recheck wiring just in case for the tiniest strand of copper can create havoc.
** motor - but thats very very unlikely as the symptoms aren't right
**mechanism - ditto - doesn't match symptoms

So

If its not fixed by removing the bulbs it may well be a decoder fault.... try another perhaps

fingers crossed

Richard

Hi Richard,

Looks like a bulb problem! With both removed it runs fine, I will do some further fiddling with bulbs but will look to replace with LEDs in due course.

As always many thanks for your analysis and advice.


Regards

Geoff
 

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QUOTE (Richard Johnson @ 21 Jul 2008, 08:35) <{POST_SNAPBACK}>Hi Geoff

Hmmm.

If its only 1 loco then I really don't think is a command station issue.

OK... I'm presuming being N scale the bulbs are using white/yellow but no blue wire/grounding thru the chassis. I have no easy answer so lets eliminate what we can....

As an experiment, take out both bulbs.... does this fix it running-wise?

If it does then it may be a bulb with a semi faulty filament creating an occasional intermittent resistance from rail voltage to fuction wire - that'll be a "back door" into the decoder as the Fn wire is after all rectification - so if its broken away and contacting occasionally it will be creating all sort of interesting interference as its impedance rapidly changes as it heats/cools and lets go with vibration/movement.

Either way, bulbs can bea nuisance later on so I'd replace both with LEDs using both blue and function wire if U have wiring room.... if not, use white LEDs via function wire with the + leads to chassis and 500ohm to 1k resistors.

There's not much else it can be if the wiring is right....

** recheck wiring just in case for the tiniest strand of copper can create havoc.
** motor - but thats very very unlikely as the symptoms aren't right
**mechanism - ditto - doesn't match symptoms

So

If its not fixed by removing the bulbs it may well be a decoder fault.... try another perhaps

fingers crossed

Richard

Hi Richard.
Well done. Would the bulbs be causing too much of a drain on the decoder ? or is it simply a bulb fault as Geoff mentioned that with only one bulb working at the start it ran ok. It was when he connected up the second bulb that the problem appeared.
 

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QUOTE (TonyDaly @ 21 Jul 2008, 19:14) <{POST_SNAPBACK}>Hi Richard.
Well done. Would the bulbs be causing too much of a drain on the decoder ? or is it simply a bulb fault as Geoff mentioned that with only one bulb working at the start it ran ok. It was when he connected up the second bulb that the problem appeared.

Hi Tony - as always its a process of elimination really.

No, its not strain on the decoder.... Arnolds bulbs ae generally good qquality and quite consistent.

What was probably happening was that one bulb was on the way out, and had an intermittent internal contact at the filament. Because its made of very super thin and floppy metal, the merest vibration may make an intermittent contact then lose it again... so its hard to identify.

Because the filament is really a "resistive coil", it has a little inductance too, especially when intermittent as a coil that turned on and off randomly will generate a small field which will in turn possibly generate a bit of hash as it starts and collapses.... certainly just eh random make/break with a few Ma load via the coil will create interference.

The function wires are connected inside the decoder after all rectification and filtering, so any hash that feeds back will directly affect the smoothness of things in the very core of the decoder, causing all sorts of false readings by the processor - basically, it doesn't know how to interpret them so does silly things.

All in all most install or decoder fixes are just a process of patient elimination - take away the variables and the problem is often then much clearer.

Geoff - I'm very pleased I was able to help, as its a nice wee loco and its very frustrating when such strange things happen!

kind regards

Richard
DCCconcepts
 

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I hope you do not mind if I add my problem to this thread as I have a very similar problem on my Fleischmann loco. I have converted to DCC using Bachmann 36-553 decoder. CV8 -151 this would indicate ESU as a producer. It has Back EMF 14/28/128 speed steps and supports Lenz break sections.
As a default it is set to 28 speed steps. I use Roco MultiMouse controller with speed steps set to 28.

Loco in question BR94 Fleischmann art nr 9093, it has old type 3 pole motor, runs smoothly on all speed on DC in both directions.

Problem when running in DCC mode;
- at step 1 runs slowly with little regular jumps. I suspect CV2 needs slight increase to cure it.
- at steps 4 to 8/9 lurching movement from time to time in both directions.
It seems like motor got additional power impuls but then corrects itself.
frequency every 2-3 seconds.
- at higher speeds (step 10 and above) no problems observed.

Steps taken so far
- removed capacitor and inductor
- removed both lamps and loco body for testing
- reset the decoder CV8=8
- set values as sugested by ESU for older Fleichmann motors
CV54 - 14 to 18, tried all
CV50 - 20

Did anyone had similar problem and could suggest a way forward?

Regards,
Marek
 

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The first thing I would suggest is to change the speed steps from 28 to 128 and see if that makes it run better.
 

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Hi Marek
When you tested on DC did you use a Fleischmann controller with MSF?
That will give smooth running when the loco is not really that smooth

If the brushes are unevenly worn or coated with oil they can cause intermitant slow running on DC and DCC
The BEMF will try to compensate , with the result an uneven speed
Try turning off BEMF and test again.

replace the brushes and clean the motor interior -then test the loco

Turn the BEMF on again and test
Hope this helps
Regards Zmil
 

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QUOTE (zmil @ 6 Aug 2008, 06:37) <{POST_SNAPBACK}>Hi Marek
When you tested on DC did you use a Fleischmann controller with MSF?
That will give smooth running when the loco is not really that smooth

If the brushes are unevenly worn or coated with oil they can cause intermitant slow running on DC and DCC
The BEMF will try to compensate , with the result an uneven speed
Try turning off BEMF and test again.

replace the brushes and clean the motor interior -then test the loco

Turn the BEMF on again and test
Hope this helps
Regards Zmil

Thanks Zmil, good tip. I used Gauge Master controller for DC testing. It has some load compensation, but I don't think I can switch it off.

However, issue of brushes, cleanliness of motor and oil needs looking at. Loco is old and when I started conversion I have cleaned it and put oil on moving parts as per manual. It is possible that I was too generous or some got into places it shouldn't.

I will clean loco again over the weekend and report next week.

Regards,
Marek
 

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To add to the good advice already given there are a couple of other things to check with this motor ;

Make absolutly certain that there are no more caps on the motor backplate - FLM use tiny surface mount ones on some backplates (they are tiny little square ones).

These motors require very little lubrication so double check this.

Make sure that the locomotive runs evenly on DC (with an ammeter connected) - there may be a mechanical problem such as sticking valve gear. Also check to make sure that the wheels are even. Also check any traction tyres to make sure that they are not causing uneven running.

And lastly, the one many people often miss - the armature itself. If one of the coils look a different colour to the others or all of them show any signs of overheating replace it - it may still run OK'ish on DC but will never run well on DCC, in fact it will be worse. If you go down this route then replace the pinion from the shaft as well - this is the one that wears the most & can be diffecult to remove intact for reuse.

With a smooth mechanism & a decent decoder these "old fashioned" motors can run very, very sweetly.

Hope this helps. If you cannot obtain spares locally then send me a PM.

Please note that I have refered to the HO version here - not too sure if you have the N or HO one ?
 

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QUOTE (Marek Klimczyk @ 5 Aug 2008, 23:50) <{POST_SNAPBACK}>I did, no change I'm affraid.

Marek

*** The older Fl motors are often lumpy on DCC at slow speeds, and take quite some fiddling to get smooth. They are not very good motors really.

Try these things and see what happens

1/ Set both CV3 and CV4 to 15 for a start....

2/ then set PWM frequency low
CV49 to 1 or 17 (both OK)

3/ then set back EMF
CV53 to about 35, CV54 to about 50 (do one at a time and then check result - if some improvement is seen when you do the CV 53 and 54 changes, go back to them individually and raise/lower by 5 to see what happens then too)

4/ then set forward trim
CV66 to 6

Alternately....

you could also try a simpler approach - setting CV 3 and 4 as above, then also setting the Vmax and Vmid.... that is, set CV 5 to say 150, CV 6 to 90. This will compress the speed steps and smooth out the cogging of the 3 pole a bit, plus give a quite small step change at slow speed - top speed will also be slowed.

No guarantees, but these are the two most likely setting sequences to succeed with.... exact values will vary a bit depending on the loco / decoder - I'm presuming the decoder has full ESU capability by the way.
regards

Richard
DCCconcepts
 

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Thanks Guys for all advise. Its fantastic to have such a depth of support and ideas.

I had to go away on business over next couple days, so I will not have a chance to test your ideas till next week.

I will let you know results on my return.

Thanks again, it is much appreciated.

Regards,
Marek
 
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