JV33-130 not printing one channel

Hello everyone,

We purchased a new JV33-130 printer three years ago and had been using without it any issues, a year ago the head was replaced due to substantial damaged caused by one of the metal substrate holders. Recently, after doing a test draw, I noticed one of the channels was not firing at all while all 7 other channels were printing at 100%. I would then run a 'hard clean' maintenance routine and that channel showed as firing above 80%; in one occasion I repeated the test draw several times and the channel gradually stopped firing. This lead to believe that what it seemed a firing was actually backwash from the 'hard clean'.
I swapped dampers and the channel still not fires. Any suggestions as to what may be the issue? I called Mimaki's tech support, they suggested doing the damper swap, which I had already done, then they mentioned it might be some type of electrical issue. Has anyone experienced similar issues?
Any help on this will be highly valued.

 

Thank you Neil, I'll do a thorough cleaning of the head sealer and see what happens.