VS540 Missing Colors

[Godfrey]

Hi
I Have a VS540 which has been working well. Halfway through a job it dropped the cyan ink completely - absolutely nothing. I suspected the dampers as everything else was working. I replaced the dampers and when I fired up I had all colours back again. The following day I had lost cyan, lt mag and lt cyan. Absolutely nothing from these channels. I replaced the head cables - no effect. After "fill ink" process and "choke" process several times no joy.
In absolute desperation I replaced the dampers again. Fired it up and now NOTHING on any channel. Tried all the head fill and cleaning routines and not a drop of any colour. I'm beginning to suspect something electrical as every time I power off and on I loose more ink channels. The head was replaced about 3 months ago and has been working fine.
Any one any ideas? Is there a way to check the electrics?

 

[euronymous]

Can you pull ink through the captop from below with a syringe>?

 

[Papajo]

After changing the damper, did you make sure that you locked the part holding the dampers into place on both sides ?

 

[Godfrey]

When we do a clean or an ink fill there is lots of ink in the waste bottle.
We had not clicked the damper holding clip down properly at first but we have since fixed and done ink fill and numerous head clean.
We have the Black and magenta working again after replacing the waste pump. But no sign of any of the other colours - Cyan, Light magenta, light cyan, yellow.

 

[strypguy]

I'd use a syringe. Ink fill will waste a ton of ink. John

 

[Papajo]

The syringe has another advantage, you can feel the resistance. If there's little to no resistance, there's an air leak upper in the system. Make sure the tubes are properly plugged to the dampers. When you pull out old dampers, the lower o-rings can come off and stick to the head nipples. Also make sure that no head nipple was broken during the damper replacement and that the damper holding clip is in the right orientation (you should be able to read the letters on the top from the front of the machine).

Are the tubes over the head filled with ink ?

As long as you have even a single nozzle, the electrics are fine, the problem is with the ink flow.

 

[Godfrey]

The syringe has another advantage, you can feel the resistance. If there's little to no resistance, there's an air leak upper in the system. Make sure the tubes are properly plugged to the dampers. When you pull out old dampers, the lower o-rings can come off and stick to the head nipples. Also make sure that no head nipple was broken during the damper replacement and that the damper holding clip is in the right orientation (you should be able to read the letters on the top from the front of the machine).

Are the tubes over the head filled with ink ?

As long as you have even a single nozzle, the electrics are fine, the problem is with the ink flow.

 

[Godfrey]

I used the syringe connected to the cap top and could draw ink through the head. It looked black but then a mix of colours I guess would look black.
I attached the syringe to the ink feed lines and can draw ink through them. The dampers appear to be full.
When I changed the dampers I checked for loose O rings and broken spigots on the back of the head. All appeared OK.
Still only getting black and magenta through and not a spot of any other colour.
This problem started when the cyan stopped printing halfway through a print job.
I am begining to think its a bizarre head problem, though why it would completely stop one or more colors and leave two colours working perfectly I haven't a clue.

 

[Papajo]

There's one way to be certain that the head is properly supplied with ink. Go for a normal cleaning, the pump should suck a tiny bit of ink through the head, then the head should move left leaving a tiny gap between the head and the cap top and the pump will purge the cap top. If you watch closely with a flashlight through that gap at that moment, you should be able to see ink drops under the nozzles. That should look like 4 lines of ink drops of mixed colors. You can even turn off the machine at that point (before the head is wiped) and carefully move the head so you can have a better look. If you have 4 consistent lines of ink drops and nothing on the test print then maybe there's something wrong with the head or the electronics. I've seen a single channel fail for no reason once but that's a rare failure mode.