Z21 Power Issues?

[Darren]

Hi all, I've been having issues with trains stopping and starting on a new layout I'm building in N scale with a Black Z21. It's been occurring from the start of the build and having cleaned all rails etc, I now suspect the Z21 itself. I tried attaching a dropbox link to a short video of the System State Settings of the Z21 but haven't been allowed too. In the video you can see readings fluctuate dramatically. Electricity on the main track fluctuates between 0ma and 46ma..... 6ma, 36ma, 0ma etc. Filtered current on the main track between 1 an 6ma. The program track, (not connected!) between 0 and 6ma. Supply voltage is fairly constant, 19.6 to 20 V, VCC Voltage 12.9 to 13.1 V

 

https://www.dropbox.com/scl/fi/ofvw3kxpwhhvs16ng0kjj/20241120_064025.mp4?rlkey=w8zqg9xw00kg29b251cpphout&st=qbuoyovy&dl=0

 

Multi meter on the track shows 12V, 2.4a

 

 

Some background....

New build. (Dream layout stuff, dual track mainlines, 3 yards...)

Z21 Black purchased 2nd hand.

Only 2 loco's so far, Dapol N Class 156 and a Graham Farish Class 60. Both run erratically, jerking and stopping.

Layout has 3 x Lodi KSM's, 4 x 10836 Roco Decoders and 5 x Dijikeijs DR4088 block detector units.

Over 25 MP4 and MP5 switch machines.

All accessories running off the main bus, however have disconnected all but 1 DR4088 to test and get the same results from the Z21 System State.

 

Any suggestions greatly appreciated.

 

Darren

[chadbag]

Did you have this working previously on a different layout (temp table top or actual set layout)?

 

Being used, maybe we know now why the guy was selling it?

 

[Darren]

9 minutes ago, chadbag said:

Did you have this working previously on a different layout (temp table top or actual set layout)?

 

Being used, maybe we know now why the guy was selling it?

 

Good point, no I didn't, however it was from a deceased estate so I had no reason to doubt it worked.

[inobu]

Disconnect your Z21 from your layout and build a straight run and test. If you have the same issue on

the test track then its the Z21.

 

If you are lucky the issue is the power supply. Although the voltage looks good. When

a load is placed on the system the power supply fails.

 

Inobu

[Darren]

2 hours ago, inobu said:

Disconnect your Z21 from your layout and build a straight run and test. If you have the same issue on

the test track then its the Z21.

 

If you are lucky the issue is the power supply. Although the voltage looks good. When

a load is placed on the system the power supply fails.

 

Inobu

So hooked it up to a test track as you suggested, unfortunately, (or fortunately depending which way you look at it), got the same fluctuating readings and stalled trains. It's the Z21. I will change the power supply over first before writing the Z21 off completely though. Thanks for your help.

[inobu]

Hopefully its the power supply.

 

Inobu

[Darren]

I've completed a reset of the Z21 and under advice from the Roco/Fleischmann Z21 Users Group, left the default output at 18v. Now everything seems to work fine. As pointed out to me in DCC world it is the decoder that provides 0-12v, not the power supply directly. So the motors are protected. All NMRA standard decoders must be able to run on up to 22v so this is well within the parameters. Thank goodness it wasn't the Z21! Thankyou all.