MK Nozzle Check Completely Blank after MK--->PK---> MK black ink switch on the Epson 3800

My plan was to never switch from MK to PK, but of course Murphy’s Law prevailed. I have a 3800 with the dreaded damper problem where the PK cart drains completely after a MK to PK switch. More recently, I had good nozzle checks throughout. However, after switching back to MK, now my MK nozzle check is completely blank. I know it’s not a clog because it happened immediately after the darn switch.

The last time I inadvertently switched to PK (yeah, it’s happened before), I did an Auto Nozzle check and it practically filled up my maintenance cart and ended with an Error on two tries. But it eventually came back.

I tried printing a full page of MK to no avail. I believe there is lots of air in the lines. How do I replace the air with MK ink? I would give up except I have carts mostly full with ink and before this the printing was going well.

Let me add a few more details in anticipation of questions that may arise from my initial post.

The MK cartridge is more than 1/2 full of ink. The circle and rectangle chambers are more than 1/2 full of ink.
I have been printing a 5x7" or letter-sized print at least every 5 days and sometimes more often for the last 1.5 years.

So far, I haven’t found anyone with the same triggering cause and circumstances as mine. However, I came across solutions for somewhat different issues and am wondering if someone could at least provide the pros and cons of these two approaches:

  • Fill the PK cart with Piezoflush and use Quad Tone RIP (QTR) to fill the PK line and damper. Would I need to first do a MK to PK switch before using this method?

  • Do Auto Nozzle Checks or Power cleaning. If there is air in the head/damper, will this work at all? I just don’t want to attempt this if it is known to make matters worse and possibly burn out the head.

Thanks in advance.