print is loosing color half way through the job

[TOM0703]

Half way into the printing some banding appears and it seams some printheads don't work. We exchanged 3 printheads, all tests and diagnostic images are excellent / then the printer works fine with 1 or 2 prints and they same is happening again. All cartridges ok all diagnostic ok. all aligned and cleaned numerous times. Now we don't know what else we can do.

Many thanks for any hints 

[Jorge70 · Accepted solution]

Hi.

The printer have a problem with ink tube system. One or more tubes are clogged. Looking for Youtube how You can to do unclogged the tubes. after you do this you must change the heads for new ones.

Best regard.

[TOM0703]

Many thanks / that certainly is the problem although complicated to fix. Hope we will find some help. 

Best regards😅