Epson 9900 dropping part of LLK channel, Help Needed!!!

[hilljf]

To all the experienced users of this fine machine, I would appreciate your help and advice.   I have owned this Epson 9900 for about 5 years and it has served me well.

About 2 months ago, I observed banding which would start about six inches into a print.   A nozel check showed that the middle portion of the LLK channel was dropping out and not printing.   The area of missing nozels is about six rows up from the bottom of the test print and all or portions of the next three to 4 rows would go blank, everything else would be good.   A simple cleaning or clean pairs would bring the ink back and the nozel check would print complete.  So this would indicate that it is not a clog.  Print an image and the banding would reappear into the middle of the print.

I wasted a ton of ink with various cleaning combinations (power clean, etc.) but the same behavior.

Called Epson and they sent out a tech from Decision One.   Also, I researched the issue and found that the Pro 7900 and 9900 Field Repair Guide on page 233 describes this behavior and suggests replacing the Dampers as the solution.  So the tech came out and replaced the Ink Exchange unit which also includes all the Dampers.  But following reassembly of the machine and various cleanings the exact same problem persisted.   Now with $600 all ready committed to the service call and the tech having no idea what to do next, I put a hold on further random parts replacements.

I really like this printer and it works great except for this small but fatal flaw.   I would appreciate any insight into how I can fix this fine machine.

thanks, John

www.johnfhill.com

[Paul2660]

Based your experience and Eric's (follow the huge thread started by Eric on this site), I am starting to believe this type of clog is nit a clog at all but instead some form of electrical issue.  Ink controller or channel.  Eric's results showed his 1/2 half clogged head was totally clear of any ink when they tore it apart. 

If the damers did not fix your printer, you may have to replace the head.  Especially since it sounds like you are staring out with a good nozzle check then developing the banding later on in the print. 

Paul C

[pfigen]

With my five year old 9900 and the same exact problem, it was print head, pump and cap station along with new wiper assembly. Eighteen hundred dollars through a third party repair outfit here in Los Angeles. Now back running perfectly with a Honeywell humidifier and a hygrometer to monitor in the print room. The Decision One guys here in L.A. are great, but they do vary around the country. Many just replace the parts Epson tells them to and are at a loss to actually diagnose anything on their own. You can buy the head from Epson for $1200 but it's $1800 when you get it through D1. Just another way to make you feel great.

[Paul2660]

Remember, it's not the head as much as the re-alignment.  This requires special software and a bit of training. 

Check out Eric's main website, if you are thinking about doing this yourself, as he has a full length video that covers the entire process.

Paul C.

[hilljf]

So, even though there are no clogs, are you all suggesting that the head is somehow failing to "pull ink" through?

Thanks,  John

[Paul2660]

Yes..  I think this is a more common issue than others realize.  I didn't realize just how possible was until Eric dissected his old 7900 head with 1/2 half of the PK ink missing.  No ink clogs were anywhere to be found.  This points to some form of electrical damage since actual ink was not causing the problem.

Take minute to read the last series of posts in Eric's long running thread in this forum. 

Paul C

[BrianWJH]

About 2 months ago, I observed banding which would start about six inches into a print.   A nozel check showed that the middle portion of the LLK channel was dropping out and not printing.   The area of missing nozels is about six rows up from the bottom of the test print and all or portions of the next three to 4 rows would go blank, everything else would be good.   A simple cleaning or clean pairs would bring the ink back and the nozel check would print complete.  So this would indicate that it is not a clog.  Print an image and the banding would reappear into the middle of the print.

I wasted a ton of ink with various cleaning combinations (power clean, etc.) but the same behavior.

Called Epson and they sent out a tech from Decision One.   Also, I researched the issue and found that the Pro 7900 and 9900 Field Repair Guide on page 233 describes this behavior and suggests replacing the Dampers as the solution.  So the tech came out and replaced the Ink Exchange unit which also includes all the Dampers.  But following reassembly of the machine and various cleanings the exact same problem persisted.   Now with $600 all ready committed to the service call and the tech having no idea what to do next, I put a hold on further random parts replacements.

I really like this printer and it works great except for this small but fatal flaw.   I would appreciate any insight into how I can fix this fine machine.

thanks, John

www.johnfhill.com

Hi John, clearly you have ink starvation happening with the LLK, so replacement of the dampers would be a logical step, looking further into the issue I would suggest checking the following possible causes before pointing the finger at the head failure, mainly because the LLK does produce some print on a nozzle check.

Possible causes:

   LLK cart has an air leak
   LLK pressurisation tubing has an air leak
   LLK ink line has air in it (possibly because of a pressurisation leak)
   LLK Tank valve assembly has a faulty or partially blocked valve
   LLK ink line has ink clumping restricting ink flow

Worth checking the above before going the expensive route of printhead replacement which may not fix the issue.

Brian.

[datro]

Hi John, clearly you have ink starvation happening with the LLK, so replacement of the dampers would be a logical step, looking further into the issue I would suggest checking the following possible causes before pointing the finger at the head failure, mainly because the LLK does produce some print on a nozzle check.

Possible causes:

   LLK cart has an air leak
   LLK pressurisation tubing has an air leak
   LLK ink line has air in it (possibly because of a pressurisation leak)
   LLK Tank valve assembly has a faulty or partially blocked valve
   LLK ink line has ink clumping restricting ink flow

Worth checking the above before going the expensive route of printhead replacement which may not fix the issue.

Brian.

+1

Over the years I've had a few cases of similar weirdness on my 7900, and in all cases (at least for me) replacing the cartridge was the solution.  I think there are cases where cartridges fail (or fail intermittently) that are not picked up and reported by the printer.  This seems to happen most often when the cartridge is down to < 5% ink remaining. Even things like the sounds made by the printer can give you a clue that there is a cartridge or pressurization problem.  Several months ago I started hearing the "pressurization sound" much more frequently than normal, and sure enough I started having problems with missing Cyan nozzles (cartridge was at 1%).  After replacing the cartridge, the frequent pressurizing sound stopped, and Cyan was good again.

Dave

[davidh202]

Hi John, clearly you have ink starvation happening with the LLK, so replacement of the dampers would be a logical step, looking further into the issue I would suggest checking the following possible causes before pointing the finger at the head failure, mainly because the LLK does produce some print on a nozzle check.

Possible causes:

   LLK cart has an air leak
   LLK pressurisation tubing has an air leak
   LLK ink line has air in it (possibly because of a pressurisation leak)
   LLK Tank valve assembly has a faulty or partially blocked valve
   LLK ink line has ink clumping restricting ink flow

Worth checking the above before going the expensive route of printhead replacement which may not fix the issue.

Brian.

I totally concur with that assessment, that was how I was taught as a camera tech back in the day, take the most logical and inexpensive step first. I would have also thought "dampers" as a first choice given the age of your printer, but since that didn't do the trick, LLK not feeding the head due to those reasons would be my next educated guess. !!!

David

By all means follow up and please let us know the outcome. Thanks!

[davidh202]

Dave,
I also concur with what you say about low cart.
I have posted many times that when I have dropout on either my 7900 or 9890, it  usually coinsides with a cart or two at 1% level warning. This is especially true after a PK/MK (visa versa) switch. I immediately remove the old cart (s), and replace them, turn the machine off and reboot allowing the pressurization system to recharge the lines.  It just isn't worth starving a nozzle or drawing air into the lines, and possibly destroying a head for a few $ worth of ink ;-)

David