Z21 problems

[GR2208]

Hello.
Not sure if anyone can help i doubt it as the place i bought the z21 from cannot help just says its my wiring which is rubbish all else works fine. Anyhow here goes.

1st problem.I have the Bachmann "Mauritania" class 40 With Zimo sound decoder and the sounds are superb, however it runs great on other layouts it will not run on mine. When i activate it on the track it starts up all sounds work fine until i try to move it then it stutters and stops i push it and it moves a bit then stops. Sometimes it will start to run then stops no sounds no nothing until i push it.
2nd problem. I cannot run more than 4 locos or they all slow down to a crawl or stop even on full speed they just run slow or not at all. Any help will be appreciated but i cannot see it. The Class 40 will not run on the programme track either as all the other locos will.

[Walkingthedog]

Silly question first. Is your track and wheels spotlessly clean?

[Brian]

Also, do you have a DCC Power Bus pair of generous sized wires running under the baseboard and onto which smaller Dropper wires connect to the rails above? - Ideally every piece of track has a pair of droppers soldered on to their rails.

It is not normal to have locos "Running" on a Programming track, as the Programming output should be a very low current to help prevent decoder failure, should a decoder be wired incorrectly. The Programming output current should not allow a loco to be driven. It may move fractionally during programming though as this is normal a sign of the decoder being programmed correctly. The only exception would be is where the Programming track is switchable between Programme and Normal DCC.

[darkscot]

It shouldn't matter too much in this case, but just for clarity do you have a z21 or a Z21?

Whichever you have, the output is 3amps so should easily drive one loco with sound and should power more than that. I have a z21 and my wiring is pretty rubbish (keep meaning to sort it), but I have never had any issues. I use mainly Zimo decoders, but every other brand works fine. I suggest try getting help direct from the manufacturers:

https://www.z21.eu/en/faqs-support/contact-hotline

Also try setting up a simple loop of track to do some testing.

[Rog (RJ)]

I think this is something to do with the PWM frequency of the supply to the motor. Zimo set a relatively high frequency of 40KHz I think. There's a way to alter it via CVs but I can't tell you which, you should be able to find out from the very comprehensive decoder user manual.

[dtb]

I have the z21 as a second back up DCC control. I use a PA2 with 2 controllers and it's always flawless but when using the z21 so many loco's stall on points. Why should this happen on one DCC system and not the other!

I don't think the z21 or the Z21 is a premium controller and I am looking to replace this with a better second controller.

[GR2208]

Silly question first. Is your track and wheels spotlessly clean?

Of course always clean as i said all other locos no problem.

[GR2208]

Also, do you have a DCC Power Bus pair of generous sized wires running under the baseboard and onto which smaller Dropper wires connect to the rails above? - Ideally every piece of track has a pair of droppers soldered on to their rails.

It is not normal to have locos "Running" on a Programming track, as the Programming output should be a very low current to help prevent decoder failure, should a decoder be wired incorrectly. The Programming output current should not allow a loco to be driven. It may move fractionally during programming though as this is normal a sign of the decoder being programmed correctly. The only exception would be is where the Programming track is switchable between Programme and Normal DCC.

I know how programme tracks work but the locos will move a bit either way but the class 40 does not it was just something to add to the topic. I have only to wires running to track but there are several droppers as i needed them, i did not know about powerbus stuff when i first got back into model rail but everything runs fine as long as no more than 4 locos .I forgot to say when i first had the Z21 all was ok could run more than 4 locos.

Thanks for reply.

[GR2208]

It shouldn't matter too much in this case, but just for clarity do you have a z21 or a Z21?

Whichever you have, the output is 3amps so should easily drive one loco with sound and should power more than that. I have a z21 and my wiring is pretty rubbish (keep meaning to sort it), but I have never had any issues. I use mainly Zimo decoders, but every other brand works fine. I suggest try getting help direct from the manufacturers:

https://www.z21.eu/en/faqs-support/contact-hotline

Also try setting up a simple loop of track to do some testing.

Thanks i will try the manufacturers but have asked the Z21 people years ago they simply said get in touch with supplier which i did and found not wrong when sent back.

[GR2208]

I think this is something to do with the PWM frequency of the supply to the motor. Zimo set a relatively high frequency of 40KHz I think. There's a way to alter it via CVs but I can't tell you which, you should be able to find out from the very comprehensive decoder user manual.

Thanks i will check it out.