Model Railway Forum

Help please. I have just fitted a Next18 Gaugemaster decoder to a Planet Industrials Kerr Stuart ‘Victory’. I am sure that the chassis ran correctly before I put the body back on. Now, when I key in forward on my handset the loco goes into reverse and when I key in reverse it goes forward. What have I done wrong? Any suggestions will be gratefully received!
P.S It’s the first time I’ve fitted a decoder myself.
P.P.S I thought it was all going too smoothly!

You will need to change cv29 - this calculator will do the job.

http://www.2mm.org.uk/articles/cv29%20calculator.htm

Exactly as Steve has stated.... Add (or subtract) 1 to whatever is the current value in CV29 e.g. if CV29 reads a value of 6 then make it 7.
So an even number in CV29 then make it odd by adding one If an odd number in CV29 then reduce it by one to make it even.
Of course you need a DCC system that can change CV values and ideally one that can read them too.

Thanks Steve and Brian. I am using a Gaugemaster prodigy but have no idea about CVS as I have only used the very basic functions. In the past, all decoders have been fitted for me and I have merely changed the address so I have no idea how to add or take off 1 from the present settings. I will have to do further reading or keep the loco as is.
P.S The manufacturer of the loco gave the same advice as you supplied when I contacted them.

This should work:
Put the loco on your programming track and select the 'prog' mode on the handset.
Key in the address of the loco and press enter.
You will then get the screen that says SV (start voltage) - just press enter and it will retain its existing value.
Do the same with the next three options ACC (acceleration) DEC (deceleration) TV (max voltage although I call it terminal velocity to match the abbreviation)
At this stage you will see CV in the screen, key in 29, as in CV29, and press enter.
It should now say VALUE or something similar.
Key in 39 and press enter. (I got that value from the calculator to give you DC disabled to prevent runaways and the long i.e. 4 numbers for a loco address and hopefully forward direction.)
Test on the layout to see which direction it goes in.
If it still goes the 'wrong' way, repeat all the steps above but enter 38 as the value for CV29 and test again. It should now reverse the direction of travel.

Many thanks Steve. I’ll see if I’m brave enough to have a go. The alternative apparently is to change the grey and orange wires around and re-solder them but they are very tiny. The loco runs superbly and slowly - it’s just a shame that I have the direction problem. I’m very poor regarding technology so find understanding CVS and the like very challenging.

Bandit Mick wrote: ↑Fri Dec 23, 2022 10:29 am Many thanks Steve. I’ll see if I’m brave enough to have a go. The alternative apparently is to change the grey and orange wires around and re-solder them but they are very tiny. The loco runs superbly and slowly - it’s just a shame that I have the direction problem. I’m very poor regarding technology so find understanding CVS and the like very challenging.

CV29 is the only one I profess to understand (and possibly the only one I ever change!). The steps I outlined (I use the Prodigy as well) are quick and easy and certainly a lot safer than sticking a soldering iron into the innards of a loco.
And I have to do the same thing later for my new A1/3 so it’s a fairly common problem with a routine solution.

A further tip - if it all goes wrong, follow exactly the same steps as above but at the CV screen enter 8 (instead of 29) then enter a value of 8. That will reset the decoder back to its factory settings (including the address which will revert to 0003) and you can start the programming all over again.

Remind me why I run DC

Only joking Brian.

No offence taken Steve. T-Rex didn’t have to have its CV's changed, and it existed for 3.6 million years.