Thor

You do not mention which controller you are using.
That information would be useful to know.

Reason is :
The CS2/CS3 are multi-protocol controllers.
They can run MFX, DCC, etc.

I have found that when the loco hits a dirty patch of track, or generates a small short circuit on the layout, then the loco can speed off as you describe.
I think that the loco sometimes gets confused which protocol it is running, maybe thinks it is momentarily DCC.

In such cases, I switch the DC protocol off on the decoder.
Go to Formats in the CV variables, and switch off all of the DC variables. Set them to off.

I also set my CS2 to run protocols MFX and FX only, so switch off DCC on my CS2

I think that I have solved the problem in this way.

Regards
John

I will try Your proposals. Also noted that when (if) power was lost over «longer» period(still did not need to move loco manually to obtain power) then the decoder restarted train from standstill to set power without the formula one acceleration.
Finally: I will try also a power pack. Should also help avoid this….
Thor

Wow Jean😳
There is indeed a lot I do not know…
Actually did not check anything of what You decribe and do not know if I understand all of it. But I will try😂
The loco already had a decoder installed. (From what you tell it was maybe originally analog?) anyway, I just replaced the existing decoder and took the shortcut: desoldered existin cables from both and re-used the existing cables and soldered them to the relevant points on rhe new dwcoder, adding cables to speaker and the two smokestacks. The spring plate for the smoke unit was missin in the loco, so I soldered the cables to the pin at the bottom of the smoke unit. Worked, bu may melt off🙄 Time will show.
Thanks for info and suggestions. I will try to improve.
Thor

Turn off the protocol analog in the decoder and the problem should bei solved.

Hi Thor!

Look at CV 29 or look also in your manual:


29 Konfiguration: 0 – 7


Bit 0: Richtungsverhalten der Lok umkehren:
0 = Richtung normal;
1 = Richtung umkehren; 0 / 1 =
0 / 1


Bit 1: Anzahl der Fahrstufen, Halbstufen: 14 oder 27;
0 = 14 Fahrstufen;
1 = 27 Fahrstufen bzw. Halbstufen; 0 / 1 =
0 / 2


Bit 2: Analogbetrieb aus-/einschalten:
0 = analog aus;
1 = analog ein; 0 / 1 = 0 / 4
Bit 3 - 7: immer 0, Bits werden nicht verwendet; 0


This behaviour ist also called leapfrog.

Lothar

Edited by user 25 May 2023 19:56:25(UTC)  | Reason: Not specified

Just to update.. and some new Questions...
I do not use my layout much during summer, but now the nights starts to get long in the north...
I never managed to fix the Leap-frogging behavior of my 3702 Borsig last spring...
Now I have tried to learn about the CV's, motor types etc..
Firstly: The loco is working now and it was my own stupid fault. I had inserted two smoke generators and had the idea of being kind to the decoder and use one aux- output for each smoke generator..(since current requirement for both seems to be a bit higher than allowed max for decoder)
During the process I had soldered the cable for first smoke generator to AUX1 and the other(error) to the side-by (common/orange) output for Current return for all AUX and light outputs. Ergo connecting the orange common orange current return to earth(via the smoke generator) when disconnecting the smoke generator cables from decoder the loco behaved well. and decoder does not seem to be damaged:-)

Then the questions:(MSD3 Decoder 60975)
If I use MFX: Which CV tables to use? DCC or MM/fx?
And if choosing MFX; How and what to Disable(both DCC and MM(fx)?
(And analog? all?)

Finally; due to the Leap-frogging i was advised to check CV for motor type..
I found the Loco to have a five pole rotor..

Then CV tables does not mention my 5 pole motor as type? What to choose... and if another loco: How to identify motor type by looking and transferring this to correct CV?
Seems there is a long way from Marklin part no for motor or Loco to get the correct CV Value..

regards

Thor

Hi Thor
Here is the manual for the 60975
https://static.maerklin....bb60f4f6131663855985.pdf

Which protocol to use?
- If you have a CS3 or CS2 then no question, MFX has the most potential and using these stations is very user friendly
- If you use other types such as ECOS, then setting MFX CVs can be difficult at best or impossible. Then, next best choice is DCC.
- If you use an older station (MS1, etc) then MM2 CVs is the remaining choice (common CV list with MFX, but Märklin encourages you to use a CS3 or CS2 for MFX CVs).

Motor Types
The key motor types to identify absolutely:
- the DC motor (Hard of soft) include the Märklin historic 5 pole HDLA
- the bell armature motors (Glockenanker Motoren)
- the SDS (sinus motors)

Specifying one type (of the above list) for another can lead to non-fonctioning at best or damage. Universal motors (winded inductor) cannot be used with this decoder.
Sometimes, a DC motor may be hard to identify (DC Hard, DC Soft) but it is my experience that using either has no consequences (so check with one or the other, which gives the bet results)

Motor type setting
The motor type should be set in CV 52 see page 40 of the manual in English
The decoder makes no real difference between 3 poles and 5 poles. Depending on the number of motor poles and the gears, you may have to adapt CV57 to synchronize the number of chuff with the wheel revolution and the number of steam cylinders (2, 3 or 4 cylinders loco.

Yes, adjusting CVs is tricky and Märklin advice is NEVER change a CV before checking if it is documented. Some CVs are linked together (motor type SDS and CV56=0)
Last: the automatic calibration (once the motor type is set) is just great: install the loco on a loop of R2 or higher radius, flat (no incline), write CV7=77, with digital power on, turn the speed knob of your loco, to get it started and let the procedure take it from there (don't interfere until finished). The decoder will set its less proeminent CVs for you.
Cheers
Jean

Thanks a lot for info. I use the CS3 to control the Locos and edit Decoders if required. In general I have not looked to deeply into this CV thing before I did this Soldering error with the new MSD3 Decoder for the Borsig 3702.
I use MFX (I think) how to know? for the MSD3 decoders I have installed, and assume also for the Locos with Factory Decoders with MFX... This had been more or less plug and play...

My plan now was to disable uneccesary things..(if running MFX Should I disable MMfx or DCC or both??

But since everything now seems to work maybe I should let it be as is? in general I have only edited max speed acc/Decc Delay, Sound volume and acc curves I think...

Lot of excuses since i do not yet get the full logic of this.

Regards

TIE

I agree with Jean.

I have never had any protocol conflicts and I run MM (a few), mfx and dcc in a mix without any problems.

I see advice to disable unused protocols, even from Marklin, but I don't understand the need.