Decoder in soon to be released Saxon 2-10-2

[Neil Robinson]

I've had one of these LGB 21480s on pre order for a while and am looking forward to receiving it in the next couple of months or so.
I've noticed that LGB have published the instructions in advance of release. https://static.maerklin.de/damcontent/3d/3f/3d3f751b810109a38913dfc50697f1881638425227.pdf
Sometimes I run my layout on Piko DCC control and other times plain DC as only six of my locos are chipped, four ESU and two Massoth.
Some time ago perceived wisdom for a system like mine was to first run a modern Marklin LGB loco on analogue and then disable the mfx option. When I read page 11 of the instructions for the 2-10-2 it appeared that register 50 is the appropriate one to change in order to do this. I note the default value is quoted as 15 yet, by my maths at least, turning all options on would give a value of only 14.
What am I missing? Is there anything else I need to be aware of?
I'm buying direct from Germany so I really really don't want to foul it up and return for repair.

 

[PhilP]

I think you will find you are not able to alter bit0 of CV 50..

This was a 'feature' we found in the early days of these decoders.
Write decimal 10 to CV 50,then read it back, and you will get '11'.

We also found the Massoth 'change address' function on their Nav + CS 'failed' as it changed a number of CV's.
These are not necessarily the same, or present, in a MFX decoder, so it failed.

Better to do it long-hand, following the calculator on the Marklin site.

PhilP.

 

[phils2um]

I note the default value is quoted as 15 yet, by my maths at least, turning all options on would give a value of only 14.

Hi Neal - There is one thing to keep in mind when converting binary to decimal. If all the bits are "1" (on) the decimal equivalent is always going to be an odd number. That is because the least significant bit adds 1 to the decimal equivalent of all the other bits which are even decimal values (2, 4, 8, 16, etc.) when on. An even decimal number always converts to a binary with the least significant bit=0 (off) and vice versa.

Better to do it long-hand, following the calculator on the Marklin site.

Yes, Its tedious but makes sure you get what you expect or at least know exactly what you changed!

 

[phils2um]

Some time ago perceived wisdom for a system like mine was to first run a modern Marklin LGB loco on analogue and then disable the mfx option

Actually I think you'll find you need to run it on DCC system using the initial default address 3 if you want to be able to read the true CV values on a DCC service (programming) track. The decoder "remembers" it was last used on a DCC protocol system when you do this. See posts 27, 28 and 29 here https://www.gscalecentral.net/threads/mfx-decoder-sound-on-analogue-power.315607/page-2

 

[Dan]

How to change the Marklin MFX decoder depends on the DCC system one is using. My Zimo MX10/32system has no problem with writing CV 50 to 2 and then reading it back and it is 2. I have done this to at least 6 different locos to date.

 

[Neil Robinson]

I may have solved this. I discovered on a set of instructions for an earlier loco, CV 50 bit 0 is labelled as analogue ac off/on.

When I get my loco, it's allegedly in transit according to FedEx, I'll run on address 3 briefly then read CV50. I'll then set CV 50 to 8 less than the original reading.

 

[phils2um]

How to change the Marklin MFX decoder depends on the DCC system one is using. My Zimo MX10/32system has no problem with writing CV 50 to 2 and then reading it back and it is 2. I have done this to at least 6 different locos to date.

HI Dan,

Did you run the locos on analog DC then try reading the CVs without running again on DCC? Did you try reading CVs after running the locos on a mfx system?
You may find things are not quite as straight forward with MLGB multi-protocol decoders as you perceive, even with your Zimo system. But I could be wrong.
In any case, I highly recommend Neil (and anyone else intending to use DCC to operate MLGB locos) run his new loco on a DCC system immediately before trying to change any CVs using a DCC system.