This is an issue with the Digitrax PR3 and not JMRI.
Below is from the JMRI website
Using the PR3 programming track to program Non-Digitrax Decoders
To implement that "neutral mode" described above, the PR3 automatically writes CV128 to 0 or 1. This happens when a JMRI throttle is used to run the locomotive on the PR3 programming track, and there's nothing JMRI can do to prevent it. Unfortunately, this can interfere with the CV programming on some non-Digitrax decoders. For example, it will set the "Master Volume" CV128 on some SoundTraxx decoders to a very low volume.
If you are using the PR3 with a decoder that uses CV128 for something, you should either not use a JMRI throttle to run the locomotive on the PR3 programming track, or remember to rewrite CV128 with the right value just before removing the locomotive from the track.
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Peter Ulvestad
JMRI Users Group Moderator - ( )
Tam Valley Group Moderator - ( )
Sprog-DCC Group Moderator - ( )
Edmonton Model Railroad Association -
Peter Ulvestad