locos wont stop

[ryan1]

Help. I have 2 locos that wont stop once set in motion, in either direction. At first I thought it was maybe the decoders (both Zimo. 1 MX622 & 1 MX621) so changed them to Lenz silver minis but no different. Any suggestions please people?

 

Cheers

[Ray H]

Does that happen in both directions.

 

Have they ever stopped when you wanted them to?

 

Can you try the decoders in different locomotives and see what happens?

 

Have you tested them on dc?

 

What happens when you put them on the layout but don't touch the throttle - i.e. leave it set at zero?

 

Can you set them in motion, lift them off the track and then put them back? What happens then?

[ryan1]

7 minutes ago, Ray H said:

Does that happen in both directions.

 

Have they ever stopped when you wanted them to?

 

Can you try the decoders in different locomotives and see what happens?

 

Have you tested them on dc?

 

What happens when you put them on the layout but don't touch the throttle - i.e. leave it set at zero?

 

Can you set them in motion, lift them off the track and then put them back? What happens then?

Yes both directions.

They sometimes stop.

Fine in other locos.

I don't have access  to DC.

No problems set at zero.

Keep going if lifted then replaced.

Also sometimes ignore emergency stop but eventually do.

 

[34theletterbetweenB&D]

I have seen this type of problem twice. It was the suppression network in both cases, resonant with the circa 8kHz of the DCC signal. A quite high pitched whine was audible when near the affected locos. Removal of the capacitor(s) and choke(s) cured it completely.

[RAF96]

Quote

I don't have access  to DC.

 

 

Simply use a 9v brick battery across the loco wheels or separate test track rails.

[geoffers]

Have had similar issues in the past. Taking out the capacitors round the motor solved the problem. Maybe that is the problem. I have found that a Zimo chip usually deals with the capacitors but obviously not in this case. Beware if you choose to take the capacitors out as they can be hidden or, as I have done, you mistaken cut the motor leads.

[ryan1]

Update - took out capacitors and changed motors (was doing that anyway) and no difference. Played with CVs and changing CV4 to 2 was the only one that allowed the locos to stop. Any other setting didn't work.

[pauliebanger]

17 hours ago, ryan1 said:

Update - took out capacitors and changed motors (was doing that anyway) and no difference. Played with CVs and changing CV4 to 2 was the only one that allowed the locos to stop. Any other setting didn't work.

 

Are these decoders set up for manual braking?

 

What was the value in CV4 before you changed it?

 

What are the values in CVs 309 and 349?

 

Which software version is loaded? (CV 7 = main version number, CV65 is subversion number).

 

Best regards,

 

Paul

[Mike Buckner]

On 22/02/2020 at 22:26, ryan1 said:

At first I thought it was maybe the decoders (both Zimo. 1 MX622 & 1 MX621) so changed them to Lenz silver minis but no different.

 

This suggests to me that the problem does not lie with the decoder. Bit of a co-incidence if all the decoders have the same fault.

 

What do you mean by "won't stop"?  Do you mean the loco slows down to a crawl, then continues at a crawl forever?

If so, it may be that the control item's minimum speed is 1.

 

Edited March 1, 2020 by Mike Buckner
spelling

[RAF96]

How is your controller connected to the track. Is it by way of a commercial clip pr power track rather than wires soldered direct to the rails.

 

If its a commercial connector has it got a capacitor inside. If so clip it out as it will interfere with the DCC signal.

[ryan1]

On 01/03/2020 at 15:35, pauliebanger said:

 

Are these decoders set up for manual braking?   NO

 

What was the value in CV4 before you changed it?  1 But also tried zero. Once I had success with 2 didn't try any others

 

What are the values in CVs 309 and 349?  Don't exist on these decoders

 

Which software version is loaded? (CV 7 = main version number, CV65 is subversion number). MX621 - CV7 = 30, CV65 = 36

and MX622 - CV7 = 36, CV65 = 5

 

[pauliebanger]

4 hours ago, ryan1 said:

 

I realised after my post that you mentioned Lenz decoders giving similar problems, so manual braking is a red herring, sorry.

 

 

 

I add the following just to explain the reason for my (now redundant) questions.

 

The CVs 309 and 349 are used to set the Zimo brake key and braking force respectively, but the decoder software version must be recent enough to support these features.

 

The MX621 software cannot be updated to aversion which supports the ZIMO manual brake feature, but the MX622 can be updated to the current SW version, V39.0. This would enable manual braking if you wished to do so.

 

Best regards,

 

Paul