Need Help VS-640 Head dripping/spraying yellow ink

[polystick001]

After printing a large amount of motives with more than 90% yellow, we keep getting a problem with one or more of the yellow nozzles.
They keep shooting out yellow ink on the complete width of the printer, and we get a yellow line throughout our whole printing.

As I wanted to clean the head (maintenance->cleaning) the head still sprayed out yellow ink while on the left side for cleaning.
You could see the drizzle coming out for a couple of seconds, then it stopped.
After cleaning, the yellow lines continued.
Sometimes they disappear when we pull out the power cable for an hour and after that printing motives without yellow.
Sometimes they disappear for a short time and then coming back. The phenomenon is not reproducible and seems completely random.

We reached out to a technician already, but he is not sure. He would start with replacing the ribbon cables, he said.
As they charge so much for these repairs all the time, I want to ask first if there is someone out there who has had a comparable problem.

We use original inks (Eco Sol Max 3)
CMYKCMYK
last service was in November last year (yellow lines before and after the service)
We use custom media profiles we write by ourself

If you need more information please let me know!

 

[rjssigns]

Trying pulling the Y cartridges and reinserting. Years ago I had an issue with my Roland barfing ink on the prints. Dealer said sometimes you get a cartridge that somehow gets pressurized. I didn't think it would work but it did. May have to do it multiple times though to clear it up.
Long shot but it's free.

 

[Zoogee World]

As mentioned above, try the cartridge. If it's happened with multiple cartridges, then that would eliminate that cause. The next thing I would recommend is replacing the damper, however on this machine it is very difficult to do without damaging or destroying the head. You'll need to do an empty to clear out the lines and dampers, then replace it and see if that works, if not, then the head has suffered some damage (most likely a head strike) and will need replacing.

 

[polystick001]

I think its not the Cartridge. Yellow changes pretty often and the problem is staying. But thanks for your suggestions!
Head strike could be as it just happen sometimes. Also the Head is a couple of years old already.
But the thing is, that the problem only occur when we print full yellow for a longer time.

when we print like images or so afterwards for a long time, the yellow lines disappear most of the time after around 10m printed.
That makes no sense at all...

 

[balstestrat]

My guess, nozzle mechanics is fucked up somehow. Maybe it just sticks open at some point and drains ink, then after a while closes again. -> New head.

 

[polystick001]

although we love our vs640 baby, I guess this would mean a new printer...
I think with all the repairs we need to let the head getting changed it would be something around 4k.
4k for a printer this old is very hard.
I don't like the fact, that the newer eco solvent printers have a pretty poor quality.

 

[balstestrat]

You can always try the head cables first. Then if that doesn't help, replace the printhead and other consumables $2000?
It's not rocket science. You can do it yourself.

 

[polystick001]

I mean we have the service manuals.
I think changing the cables will be possible. But I don't know if i would trust myself changing the Head properly. seems pretty complex with all the settings and calibrations you have to do afterwards.