My Epson 7800 has a blocked yellow channel (with Shade 1 Warm Neutral gloss black) that I can't open. It's also showing deflected nozzles in a few other channels that jump around after cleanings.
This is what has been tried so far, in chronological order:
- many nozzle cleaning and checks
- power clean
- cleaning capping station, wiper blade, and parking head on capping station with Piezoflush overnight
- letting printhead sit on Bounty white towel soaked in Piezoflush
- damper replacement.
- pulling Piezoflush (from a different cartridge than the Y cartridge with Piezography ink) through Y ink line to the head
- 2 power cleans after damper replacement to pressurize system/put Piezoflush through the Y nozzle in head
- printing 4 - 17" x 40" purge image for yellow channel via QTR with Piezoflush cart installed in the yellow channel. This prints some extremely faint lines at the beginning of the print, but after a few inches, nothing comes out. Also, there are some very small Piezoflush spatters on the paper.
- letting this sit overnight with Piezoflush in the Y ink line and head.
The machine was running Piezography 2 inks (matte in the PK slot and photo black in the Yellow slot). It has original capping station, pump assembly, and print head. Now it has new dampers, but prior to this problem I think it had the originals.
After damper replacement, I was able to successfully make matte prints with normal results for a day, but am now getting deflected nozzles in other shades enough to show bad banding with matte prints. This morning I have clear nozzle checks in every channel, except Y which is completely missing.
My local technician (via phone) doesn't think its head failure, but suggested that maybe the pump is failing and not creating enough pressure in the system. Would a bad pump cause this? He also suggested a bad cartridge, but I've tried a different cart filled with Piezoflush and that didn't print either.