All CV's read 255

[philsandy]

I was trying to alter some CV' s on a loco that I've had a few years and found I could not change any of the CV values ,they all read 255 no matter what value I enter.

Decoder is a ESU Loksound V4 and throttle is a Powercab. Have tried other locos and there is no problem. The loco does run OK, and I've tried a decoder reset, CV8 = 8, but it keeps reading 255. Is the decoder kaput?

[JimFin]

The code 255 usually means the software can't "see" a decoder and will generally neither read or write to it so the command CV=8 will simply not get to the decoder.

 

2 suggestions, a) try the same process on your programming track rather maintrack b) give the wheels / pick ups a good clean as there may be enough grime to prevent a clean signal. 

[philsandy]

2 hours ago, JimFin said:

The code 255 usually means the software can't "see" a decoder and will generally neither read or write to it so the command CV=8 will simply not get to the decoder.

 

2 suggestions, a) try the same process on your programming track rather maintrack b) give the wheels / pick ups a good clean as there may be enough grime to prevent a clean signal. 

 

Jim, I was using the programming track and had just cleaned the wheels.

The only thing I can change is the short and long addresses.

The manufacturer code which should be 151 is also reading 255, and the motor polarity has reversed, ie. running forwards when displaying REV, I'm assuming that is because the value of CV29 is now an odd number.

[RobjUK]

Does the loco have a stay-alive capacitor fitted? They can level out the current so the programmer never gets any feedback pulses.

 

 

[philsandy]

11 minutes ago, RobjUK said:

Does the loco have a stay-alive capacitor fitted? They can level out the current so the programmer never gets any feedback pulses.

 

 

 

No Rob it doesn't

[JimFin]

I am short of ideas after that. I am fairly convinced that for some reason the decoder and controller are not  communicating. CV 8 should always read the manufacturer - 151 as you say and CV29 would not accept a value of 255. At this point, I would be asking a pal if I could check it with his controller (or via a club if you are a member) beyond that, in Manchester, perhaps a chat and visit to The Locoshed or similar might be in order.

[HLT 0109]

I wonder if the loco is rather lightweight?  I have had the problem with small locos (I also use Power Cab) though not those fitted with Loksound decoders.  I found that adding some extra weight temporarily to the loco when on the programming track to ensure secure electrical contact between all wheels and the rails?  Something attached to the top of the boiler with Blue Tak for example worked.  You might manage by holding the loco down by hand if you can avoid any movement or shakiness.

 

Perhaps worth a try.

Harold.