This problem occurred once and I resolved it by reflashing the JTV-59 to reload the V1.7 firmware.

I am raising this discussion to document the issue and ask Line6 if they can ensure that a firmware fix is written to resolve it so it doesn't bite anyone else.

Scenario - JTV-59 on v1.7 firmware connected to X3L via VDI.   Programming patches on the X3L to save the JTV model secltion with the patch.  The X3L was connected to my Marshall EL84 20/20 poweramp.  As I was programming patches I suddenly became aware of a very annoying buzzing soundcoming through the speaker.  I didn't know if this was caused by the JTV or the X3L.  So I decided to disconnect the VDI from the JTV and reconnect it to see if maybe I had not seated it properly.  However, this did not fix the buzzing.  BUT - I noticed that I could no longer select or store the JTV model selection with my X3L patch.  Each patch input started with DONT FORCE MODEL but when I used the knob on the X3L to select Variax/JTV control, the display changed to V1.70 MODEL.  It then would not go back to DONT FORCE MODEL and would not allow any model selection either via the knob or via the controls on the JTV.  This persisted even after powering off the X3L and powering it back on and after resetting the JTV to factory defaults.  The only solution was to reflash the JTV with the V1.70 firmware and then I was able to once more correctly select and store the model selection.

Is this a software glitch on either the X3L or the JTV59 and can it be fixed?  Thanks.