Printhead change Mimaki CJV150

[Christirol]

Hello,

I need help!

I recently performed a print head replacement on my Mimaki CJV 150 and switched from 8-color to 4-color ink. I also replaced the waste ink pump, capping station, and dampers.

**Current Issues:**
1. Only 4 channels were flushed during setup; the other 4 remain on standby (no indicator lights, though the display detects them).

2. The initial nozzle test looked semi-okay: CMYK showed, but magenta produced zero droplets. Cleaning cycles did nothing.

3. After removing/reinstalling the damper to inspect, **yellow also stopped working**. Further cleaning left only black ink functional; all other colors vanished.

4. In frustration, I reran the 8C→4C setup. This time, different inks were selected:
- MCK now works (without yellow).
- The other 5 ink channels failed to flush again.


- Did I damage the new print head?
- Could replacing the dampers *again* help?

Thank you so much for any guidance!

 

[Smoke_Jaguar]

When doing 4 color, the cartridges deplete one at a time, allows hot-swapping. You're fine. Just need to install the line bridge connectors that common the like-colors together.

 

[gregjordansr]

Mimaki printers really said, "Congratulations on your new print head, but here’s a side quest of despair." Definitely sounds like air, clogged dampers, or misaligned setup, don’t give up yet

 

[Smoke_Jaguar]

Note how the M is bridged to the other M, Y and Y, C and C, K and K, if those junctions are not installed, you're going to have nothing but headaches.

 

[Neil]

I also replaced the waste ink pump, capping station, and dampers.

There's your problem, I'll bet. Most likely the capping.
When inks drop out like that it's because ink isn't getting pulled through the head when you do a cleaning.