[Marek_K]

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

 

[Marek_K]

QUOTE (poliss @ 5 Aug 2008, 15:03) <{POST_SNAPBACK}>The first thing I would suggest is to change the speed steps from 28 to 128 and see if that makes it run better.

I did, no change I'm affraid.

Marek

 

[Marek_K]

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

 

[Marek_K]

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

 

[Marek_K]

Hi,

Finally had some time to try some of your advise;

I think I can say that mechanically loko and gear valves are ok.
Enginee take even current at DC (around 170mA)
However, brushes and comutator seem a bit doggy Decided to order new brushes and I have cleaned comutator using felt.

Once I get new brushes (in Poland it takes about two-three weeks) I will install them and do more tests.

First without any other changes and then I will try all CV setings described earlier.

Fingers crossed that it will work.

Regards
Marek