WIMorrison

The 177 versions of the MX617 are the (much) newer model with more memory and the capability of having more functions/CVs above CV255, though what these CVs would be used or when for wasn't said. It was inferred that the 177 version may be available in a future update of the Z21 firmware as it is Roco that restricts the ability, though I am also sure that there is some commercial agreement in place to restrict the Z21 capability to DCC Fitted decoders only. I will try pinging Roco

I have a very full and complete answer from Zimo which explains a lot, the summary of which is below. The Z21 in default state will only update decoders that Roco have factory fitted in their models, and the MX638 hasn't been used by Roco and neither has the MX617 (type 177) hence the updater refusing to update these decoders. He has advised me that there is a way to 'unlock' the Z21 maintenance tool to allow it to update all Zimo decoders, however that information is held by Roco and Zimo are not at liberty do divulge the information. Does anyone know this unlocking trick?

Even Multimeters that have true RMS will give inaccurate reading on DCC.

As suggested a quick search on Google will turn up hundreds of videos on the Z21. the official website www.z21.eu also has masses of information. Is there something specific you wanted to know?

Been using a Z21 with Railcom and Cobalts for several years and never had an issue. Have you tried issuing value 198 to the Cobalts? This deactivates the self-centering. Also, as the default setting for the Z21 is +4 on the address you may need to issue 202 rather than 198 to deactivate the feature. You can turn off the +4 feature using the Z21 Maintenance Program.

John They haven't put all the decoder files in the Z21 file as there are only 50 decoders listed in the Z21 fil but there are 69 listed in the other files and in addition there are 2 files that the Z21 cannot open. What I do notice is that all the MX617 files have different data offsets and data lengths (different from the Zimo files also) which suggests that whilst functionally and commercially the same decoder they are in fact different needing different software to achieve the same outcome. I guess we need to see if they reply to me and what they say about the differences and why some decoders cannot be upgraded using the Z21.

Absolutely possible, but a bit of a nightmare with the wiring

Paul the MX617 is listed as 197 and 177 (not 117?) and also the MX638 is listed as 193 but decoders with Start Byte 177 and 193 will not update with the message that this type of decoder is not supported. You will note that version39.0 is the version offered which is higher than the existing versions so why does Zimo list an updated software version if that cannot be applied? EDIT - they also offer31.6 for the MX621 and that is newer than what you say can be installed. something is wrong somewhere. BTW your link doesn't even show the MX617

If it possible then it will be dependent upon the ability of the display to read and display multiple decoder IDs at the same time. What display do you plan to use? FYI, I can do this easily (and do) but I am using a computer to read and display this data

done

As far as I can see, and certainly performance or CV wise there is no difference just a different value in CV250 and as you say it is in the .zsu file, but then the MX638 is also in the zsu file

Not should - will

Yes, that is what I am using and the type 177 MX617 and MX638 will not program - do you (or does anyone else) have either of these decoders and managed to program them?

Reporting back with a modicum of success (and heart back out of mouth). During the update process 2 locos (both with MX622 decoders) failed, one catastrophically although after several attempts at the hard rest procedure posted here I managed to force an update by unchecking the box to check CVs and it recovered all the settings I have two decoder types that try as I might they will not update, MX638 and MX617 which have a type of 177, those with a type of 197 updated successfully. I have 2 locos with MX638 and 3 with type 177 MX617 and the update failed on all of them ergo I think it is a definite decoder/updater issue. The other 16 locos all update successfully - and one Lenz fitted loco that I placed on the track (I thought it had a MX617) failed - good to know that it didn't wreck the Lenz decoder though What I have noticed after the update is that I now need to re-profile the speed measurement on all the locos as the top speeds are slightly different by around 5% forwards, but much the same in reverse.

Arggghhh - it looks like I picked up the old file also I will ret again tomorrow with the file you have used, assuming I can find it!

A bit more checking may reveal the reason why I cannot update any of my decoders - they ALL have a subversion number greater than that contained in the Zimo file. e.g. the MX617 in the Zimo upgrade file is for subversion 8, all my MX617 are subversion 9 and 10, for the MX638 the Mimo file version is 8 and my decoders are on subversion 10. The same applies to my other decoders.

@jpendle - I am using firmware v1.33 with 1.14 maint program and the same zsu file, and as I say - no luck

Anyone have a list of the CV 250 value for the different Zimo decoders? the manual is rather short on describing all the values as the Zimo list is rather limited - I have decoders with 177 in CV250 which I think are MX617 but are not in the Zimo list

OK, I have now tried using the Z21 Maint Program to update a MX617 - fail, MX622 - fail, MX838 fail It would appear that I 'might' be able to 'force' an update by unchecking the box for CV Verification but I would rather not do that and will just accept what Roco say in their documentation.

Interesting, I have never managed to get it to update any decoder files at all, let alone the MX617. I will try again this afternoon and see if I can have some success

What you forget is that some people like to create complex panels because it makes it look difficult thus making them appear better because they can operate the complex panel. i am though with you - simpler the better and ultimately must alway be self explanatory, if it needs instructions to operate then my objective in creating a panel has not been met.

Nigel Just to clarify the Z21 allows the reprogramming of Zimo decoders that have been purchased from Roco, but not Zimo decoders that you buy direct from Zimo or retailers.

I run the loco on the layout and keep the room quiet and listen for changes in the sound of the loco as I change the CVs using POM. This has enabled me to work out that CV56=55 or 33 on my locos and CV9 is generally sat at 95. These are the setting that I use on the MX617 and other than changing min and max speed to get realistic operation I find that these are the only 2 that I play around with.

I would check 2 things that might cause issues both related to the moving blades that are relying on the contact with the rail when closed. Firstly ensure that the blade contact points are spotlessly clean (fibreglass pencil and hover up the fibres) and also that the rivets at the pivot end are making good contact with the rail - contact cleaner for this job. i have seen both of these cause difficulties for people

Have you tried adding a route using the icon?