EPSON 7900 not charging ink

[eyescream]

Hi I'm one of the poor guys with head issues 

My EPSON 7900 started with clogged/missing LK nozzles. I was able to clean them several times but the same nozzles started to clog soon after again and cleanings did not clear them.
The quote from the EPSON service was so high that I decided to buy a new 7900.

Now I tried to fix the old 7900 by myself. I took it apart, replaced the damper unit and cleaned the head.
After putting all back together the new damper did not fill with ink. I even tried the Init.fill without success.
It goes through the init.fill process as usual but the waist ink tank stays dry. The air bubbles in the tubes do not move so as the head and damper stay dry.

I suspected a faulty new damper unit, so I put the old one back in - same result.

Any suggestions what could be wrong?

Ron

[BrianWJH]

Sounds like the pressure pump is either weak or not connected properly to the damper assembly.

You could try attaching a syringe at each damper port and sucking ink into the ink supply lines to prime each line.

Brian.

[eyescream]

Brian, how is the pressure pump connected to the damper assembly?
Isn't the pressure pump connected to the cardridges instead?

I tried to prime with a syringe, but it immediately creates a vacuum and I only get a few drops out of the dampers.

Ron

[BrianWJH]

Hi Ron, have a look at the following video link, although it's for a 4880 the important bit is the correct opening and closing of the ink supply levers when using the syringe.

There are two videos: http://www.youtube.com/watch?v=2-PqS3hzHDI

Yes, the pressure pump is connected to the ink carts.

Brian.

[eyescream]

  Ink supply levers on the 7900

Maybe the 7900 has an electrically operated valve?

Ron

[BrianWJH]

Ink supply levers on the 7900

Maybe the 7900 has an electrically operated valve?

Ron

Hi Ron, yes possibly I have the 7880 and it does have levers, if you can get the Service Manual it should answer your question.

Brian.