Need Bachmann decoder help - GP30

I just bought a Bachmann GP30 with a non sound decoder per-installed by the factory.

I can’t seem to be able to find any information on what decoder it is. It won’t read back on the programming track. (It does work and can be programmed on the main as I changed the address.)

If anyone knows what decoder it is or where I can find a CV listing, I would appreciate it.

Thanks in advance.

It is an el-cheapo ultra-low end decoder made for Bachmann by Lenz. VERY limited in what it can do. It has the basic required CVs from the NMRA standards and little else. The definition should be in JMRI - you can use it to configure CVs even if you don’t have an interface to your system. Configure the program for the Loconet Simulator, and you can open the programmer and make all the changes based on the screens. There is an additional page that shows all CV values - the ones highlighted in red are the ones that would need to be changed by your choice of settings. Proceed to program those CVs to the listed values using your system.

–Randy

It’s a stripped down Lenz decoder and has next to zilch in functions. To get it to read on your program track you will need to attach a 1k resister to the rails of the program track. After that is done you’ll be able to read it without a problem. I have two of the Bachmann GP30’s and set them up on the program track to run tail to tail.

These cheap decoders sometimes don’t put out enough current on the track for readback. Putting a 1k resistor across the programming track should fix that and allow readback.

Peter