Use a syringe and suck the ink through the damper. It's one channel thats not working. That means either 1 channel is completely dry on that head or the damper is not getting its ink. Sometimes the black seal at the bottom of the damper is a bit loose and not tight, which causes the damper to just dry the ink or doesn't let the ink get sucked probably into the print head. I have a xc-540 too.
Do you think there could be a crack on carriage on the head? I used and syringe last night and was able to pull ink through
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