Epson SC-P600 Inconsistent Nozzle Checks, Missing Channels, Why, and the Repair

The SCP-600 (RiverRat01) will be repaired after the replacement, in order, of the following?

  • Pressurization valve

    Votes: 0 0.0%
  • Ink delivery and damper assembly (plus above)

    Votes: 0 0.0%
  • Ink charge (plus above)

    Votes: 0 0.0%
  • Repair will fail despite all of above

    Votes: 0 0.0%

  • Total voters
    1

RiverRat01

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Background. Failing to abide by Jose's primary instruction to maintain ink cartridges at half full or more, I let a PK cartridge run dry. Thus. air entered the PK line and the channel quit printing. I am embarrassed to confess, this was a repeat offense. I committed the same heinous crime in 2018. I bought the SC-P600 in 2015 and am the sole owner. During my eight years of ownership, I have bought just one set of Epson ink cartridges; I only did so as a diagnostic. The vagaries of refillable cartridges are many; I suspect that I have dealt with most of them. As such, by 2017, I had installed an external waste tank.
Back in 2018, when I let air enter an ink line, I clocked through an entire waste counter reset by trying to purge air from the lines and head through nozzle cleaning and purge printing. I was about to give up, but for one last hope, I acquired the adjustment program and ran an ink charge. The P600 was restored to perfect operation. Through all of this, I resisted removing the print head or even attempting to clean the print head.
Luckily, before buying the SC-P600, I had needlessly destroy several thousand dollars worth of print heads. If you prematurely insist on generating a waterfall from a print head that is truly clogged, you might as well just stop and sell the printer for parts. Thus, in 2018, I vowed that I would not touch the P600 print head until all other possible solutions had been exhaustively tested. Finally, it was an ink charge that cured the problem.
Fast forward to 2023. The P600 is not working. I need to have a working printer within two weeks or things will get awkward. Planing for the worse, I studied printers that are currently on the market. The P600 is more than a printer to me; it is a laboratory. As near as I can tell, there is not a printer on the market that, for my purposes, would be anything other than a downgrade. Thus, a busted P600 is not an excuse for me to buy a new toy. I could by a P700 or a P900. I don't want one.
A note about me. I became an amateur radio operator at 11 years of age. Advanced Class at 13 years of age. I worked my way through college, in part, repairing audiovisual hardware; both analog and digital. Nonetheless, my career work is human repair. My hobbies include coin photography and printing.
The Problem. The SC-P600 has worked flawlessly since 2018 until last week when, no thanks to me, she sucked air into the PK line. As expected, after about 20 pages of moderate PK use, the channel went dead.
Solution 01. I immediately filled a set of cartridges with Piezoflush and ran an ink charge.
Result. Unlike in 2018 when an ink charge solved the problem, in 2023 an ink charge destabilized all channels. The yellow channel, which had been printing perfectly on a near daily basis for four years was entirely killed by the ink charge. Ironically, the PK channel is now the only channel that often shows a perfect nozzle check. Four of eight channels are non-printing.
Interpretation. My fear was that the Piezoflush may have dislodged debris from the ink lines that, in turn, traveled downstream and hopelessly clogged the print head. This fear was somewhat assuaged in lieu knowing about filtering at the dampers. I resisted messing with the print head. I found it curious that one-half the channels were either dead or nearly so while the other half were close to perfect nozzle checks. The yellow channel, which had been printing perfectly on a near daily basis for four years was killed by the ink charge and had not released a droplet. Was this coincidental to the observation that the capping station gasket has a septum that creates two chambers and, further, that the ink pump has two waste lines? Is the pump ganged? Perhaps one chamber defined by the capping gasket is not generating vacuum and, further, that one chamber services the four channels that are nearly dead? Seems a bit far fetched. Nonetheless, my P600 has gone through three waste counter resets and the capping station is the original and, thus, nine years old. Perhaps I should have replaced it after the second waste counter reset? Further, the wiper is bent away from the capping station and is warped into an "S" along the surface that should contact the head. I plan to order a new capping station assembly from Compass Micro this Monday morning; but first I want to know that the print head is good. How am I to determine this? The yellow channel has been dead since ink charge and continues to be dead after several "super" head cleans.
Questions inspired by the failure of Solution 01. Are the two chambers of the capping station independent from each other secondary to a ganged ink pump? Do each of the two capping stations service one-half of eight channels? A fly in the ointment; why does some of the nozzle cleaning cycle appear to occur to the left side of the carriage area and not even use the capping station? In regards to the head cleaning cycle what is happening during the different sounds - the "raw raw raw raw" versus the "buzz buzz buzz" versus the prolonged buzzzzzz? Is there an online resource that explains what underlies the various sounds made during a head cleaning? In the case of my currently busted P600, ink only squirts into the waste tank during the second round of "raw raw raw raw." All other instances or "raw raw raw raw" merely generate bubbles at the waste tank. Reminiscent of Lawrence Welk.

Solution 02. I swapped in a different ink delivery assembly that included the ink tank/lines beginning with the cartridge nozzles and ending at the damper assembly. I bought this delivery system a few years ago for a mere 40 bucks. It was removed from a new P600 that was being converted to DTG. The assembly was "new" but, nevertheless, had been charged with ink. I applied vacuum to each of the dampers are verified the ink was flowing through the ink lines and dampers.
Result. No meaningful changes. Four channels continue to show nearly perfect nozzle checks and four channels are nearly dead. The yellow channel has not showed any sign of life since the initial ink charge with Piezoflush. My fear is waxing that the print head is bad. Nonetheless, I resisted messing with the print head. It is interesting that after the printer has set for a few hours, the nozzle check improves. Then a single "weak" head clean further improves the nozzle pattern. But then, an additional head cleaning results in dramatically worsening the nozzle patterns. It is as if the ink being drawn out by a head cleaning is not being replaced for four channels while another four channels may give a perfect nozzle check. More and more, I am beginning to hope that the capping station and not the print head is the problem.

Questions inspired by the failure of Solution 02. I removed the dampers from the damper assembly of the original ink system removed from the P600. The dampers, when remove, easily flowed distilled water from the inlet to the outlet. When installed, however, 1CC of vacuum applied to the damper outlet would only draw about one-half CC of fluid (ink or water) and then the flow stops. On the other hand, positive pressure applied at the air intake of a cartridge mounted on a cartridge nozzle easily flows distilled water out the corresponding damper. In summary, water easily flows from the cartridge nozzle to the damper outlet when there is positive pressure at the cartridge nozzle but little water flows when negative pressure is applied at the damper outlet. This is the observation for all dampers. There appears to be a one-way valve somewhere in the ink path before the dampers. But, if so, how does ink ever get to the head? Does the print head somehow apply enough negative pressure to suck ink into the piezo channel? Is the flow of ink somehow gated in the ink path from the cartridge nozzle at the cartridge holder?

Solution 03. I am hard pressed to either buy another printer or get the P600 working again. At most, I have three weeks to resurrect the P600. If I cannot, I may buy the P900. But, I don't even want the P900. I simply do not want to patronize Epson's restriction on third party ink. As I wrote earlier, for me, a printer is much more than a tool; it is a laboratory. Thus, I am about to throw the dice and buy a brand spanking new ink delivery assembly and a capping station assembly from Compass Micro. My fear is that the print head may be dead. The yellow channel has not fired a droplet since the initial failed ink charge. I will not take on the expense/risk of a new print head. I will either accept being a slave to Epson and buy a P900 (the P900 appears to be much cheaper to operate than the P700 and I have the space) or maybe I drive into NYC and buy a working used P600.
I caved and decided to attempt cleaning the print head. Having destroyed several print heads in the distant pass by mimicking insane videos on YouTube, I settled on a most non-invasive technique that I first saw demonstrated by Kevin at BCH. In my case, however, I was less invasive than Kevin. Not only did I not remove the print head, I attempted the cleaning with the print head parked on the capping station. I had previously determined that, with the waste tank located below the level of the printer, the capping chambers would passively drain. Thus, why clean the print head in the carriage area and risk nozzles drying out? I cleaned the nozzles one at a time. Similar to Kevin's technique, I used a 2.5" length of tubing to place a column of fluid above the head nozzle. I used a 10 CC syringe that was fresh and showed no sticking when working with Piezoflush. I never exceeded more than one syringe marking (0.25cc) against either positive or negative resistance. I never reintroduced a back flush into the head. Thus, I started with a back flow until I got air never applying more than 0.25 cc of air vacuum starting with the syringe set at the 2 cc mark. I then filled the vertical tube using a needle to avoid air gaps and let the pressure generated by a 2.5" column introduce Piezoflush back into the head channel. Once Piezoflush was flowing, I back flushed again and checked for any particles. Whether there were particles or not, I discarded the back flush. I turned cartwheels to not force any debris through a nozzle aperture. When finished all eight channels were identical in hosting flow of Piezoflush from the top of a 2.5" column down to the nozzle level.
Results and Questions. I performed a nozzle check before initial head cleaning following my flushing of the head. To my delight, all eight nozzles (including the previously dead yellow channel) printed a nearly perfect nozzle pattern for the red dyed Piezoflush. My interpretation is that the printer head is good. Not unexpectedly, after a few head cleanings, four channels continued to give nearly perfect nozzle patterns and four channels, once again, went dead. My interpretation/hope is that the four channels that go dead continue to have air trapped in them and that the capping station ink pump has failed on one capping chamber and no longer provides enough vacuum to clear air in the head. Nonetheless, I do not have much confidence in my interpretation because I don't understand the head cleaning process. Does the capping station literally draw ink through the head or does the capping station merely pump ink from the chambers that is ejected by the piezo membranes? Further, does the observation that, for a few nozzle tests, all 8 channels generate a nozzle pattern, provide a favorable indication that the print head is good?

Closing Comment. Like so many things in life, the more you know, the more you have to face what you don't know. I frankly don't know how the P600, or any none-pressurized professional inkjet printer ever worked in the first place. There appears to be a one-way valve in the delivery system that would never allow ink to enter the print head. On the other hand, if there was not some kine of one way valve, ink would leak out the print head and empty the cartridges. What stops ink from merely leaking out the print heads? Surface tension? I was surprised that when I removed the damper assembly from the print head, there was no leakage from the dampers despite that I set the damper assembly in the carriage area with damper outlets facing downward. How can there be no leakage from the dampers and, yet, half the channels are printing? I don't understand how the darn thing ever worked out of the box.
 
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Ink stained Fingers

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Wow - I must admit that I didn't read your posting in all detail but I'm coming to the conclusion that you rather should look for a new printer. You would need to decide if you stay with pigment inks like the P700 or switch to a A3+ printer with dye inks like the ET-8550 or ET-18100 - both ink types have their preferred range of application.

Inkjet printing - what happens in the printhead - it's just hydrostatics as long the printer is not printing and complex hydrodynamics once the printhead spits out the droplets. just have a look here

https://ris.utwente.nl/ws/portalfiles/portal/6085963/thesis_Wijshoff.pdf
 

The Hat

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Wow - I must admit that I didn't read your posting in all detail
I did, and am as confused as @RiverRat01, it also confirms the reason why I only use Canon printers, they either work or they don’t, and are far less confusing to work with..
 

RiverRat01

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Wow - I must admit that I didn't read your posting in all detail but I'm coming to the conclusion that you rather should look for a new printer. You would need to decide if you stay with pigment inks like the P700 or switch to a A3+ printer with dye inks like the ET-8550 or ET-18100 - both ink types have their preferred range of application.

Inkjet printing - what happens in the printhead - it's just hydrostatics as long the printer is not printing and complex hydrodynamics once the printhead spits out the droplets. just have a look here

https://ris.utwente.nl/ws/portalfiles/portal/6085963/thesis_Wijshoff.pdf
Thank you for the link. The TOC indicates that the focus is mainly on the print head and not so much on external ink flow. Nonetheless, I wish I had read this article two decades ago when I first started fiddling with inkjet repair. Despite that this is Sunday, I have to head to my day job. I shall start reading the 185 pages this evening. Do you know of a similar article regarding the ink deliver system?
 

RiverRat01

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I did, and am as confused as @RiverRat01, it also confirms the reason why I only use Canon printers, they either work or they don’t, and are far less confusing to work with..
Thank you for the encouragement. LOL I have noticed that there are convoluted ink paths in the tank base that are fed by the ink cartridge. My uninformed suspicion is that they perform some sort of dampening and may be a "functional" one-way valve. Or instead, perhaps I replaced the original ink system that may have been, indeed faulty, with a second ink system that was also faulty. The ink delivery system that I swapped in was "new" but it had been charged several years ago. I hate to throw good money after bad, but I have to know; "was it 7 or was it 8."
 

nertog

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I'll try to answer a few of your question based on my experience with the R3000.

* Both halves of the capping station are connected to a single peristaltic pump. Make sure there is no dried ink on the seal or on the mesh/foam. Each halve seals 1/2 of the nozzles on the printhead
* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail.
* The capping station draws ink through the printhead, but during cleaning cycles there is a short piezo-driven jetting part as well.
* The dampers have one-way valves

I think the filters in your dampers are clogged. Based on your comments, your printhead should be good. I would replace all dampers, clean the capping station and do an initial fill.

Good luck!
 

RiverRat01

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I'll try to answer a few of your question based on my experience with the R3000.

* Both halves of the capping station are connected to a single peristaltic pump. Make sure there is no dried ink on the seal or on the mesh/foam. Each halve seals 1/2 of the nozzles on the printhead
* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail.
* The capping station draws ink through the printhead, but during cleaning cycles there is a short piezo-driven jetting part as well.
* The dampers have one-way valves

I think the filters in your dampers are clogged. Based on your comments, your printhead should be good. I would replace all dampers, clean the capping station and do an initial fill.

Good luck!
Thank you for your suggestions. I tested dampers that I removed from the P600 damper assembly and they easily flowed water from the inlet to the outlet. I did not test from the outlet to the inlet but based on your comment, I would likely have noticed a resistance to flow of water in the reverse direction of the ink path. The "functional" one-way valve effect I am referring to does not require the dampers to be installed in the ink path. If vacuum is applied to the nipple that feeds the damper inlet, little water is drawn and resistance is sustained. On the other hand if a cartridge is place on a port and positive pressure is applied to the cartridge air port, fluid easily flows out the corresponding nipple that feeds the damper (when the damper is installed). Thus, the ink path between the cartridge port and the outlet to the damper appears to be gated by a one-way valve regardless of whether the damper is installed. All eight channels from the cartridge bay show the same resistance to free flow when a vacuum is applied to the nibbles that would, otherwise, feed an installed damper. I tend to believe that this must be by design. Nonetheless, I suppose that I need to consider that I have two faulty ink delivery systems and that I merely swapped one faulty assembly for another. This is why I may just buy a third ink delivery assembly that has never been charged from Compass Micro along with a new capping assembly. My bet is that replacing the capping assembly fixes the problem.
On the other hand, if you are correct about clogged damper filters, I doubt that the capping station will correct the problem. Then I will proceed to install a new ink delivery assembly that includes the damper assembly. Proceeding from here is as much a matter of stubbornness as it is a matter of playing favorable odds given my lack of expertise.
It seems that Epson treats the damper assembly and the capping assembly as consumables. Perhaps had I replaced them before I allowed air to get into the PK line, the ink charge would have corrected the problem and this episode would already be behind me.
I have had five years of flawless daily printing since the previous episode in 2018 when I let air into the ink path. It's hard to be proactive and replace expensive consumables when things are going well. Thank you again for providing your insight.
 
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RiverRat01

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Thank you for the encouragement. LOL I have noticed that there are convoluted ink paths in the tank base that are fed by the ink cartridge. My uninformed suspicion is that they perform some sort of dampening and may be a "functional" one-way valve. Or instead, perhaps I replaced the original ink system that may have been, indeed faulty, with a second ink system that was also faulty. The ink delivery system that I swapped in was "new" but it had been charged several years ago. I hate to throw good money after bad, but I have to know; "was it 7 or was it 8."
I'll try to answer a few of your question based on my experience with the R3000.

* Both halves of the capping station are connected to a single peristaltic pump. Make sure there is no dried ink on the seal or on the mesh/foam. Each halve seals 1/2 of the nozzles on the printhead
* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail.
* The capping station draws ink through the printhead, but during cleaning cycles there is a short piezo-driven jetting part as well.
* The dampers have one-way valves

I think the filters in your dampers are clogged. Based on your comments, your printhead should be good. I would replace all dampers, clean the capping station and do an initial fill.

Good luck!
I'll try to answer a few of your question based on my experience with the R3000.

* Both halves of the capping station are connected to a single peristaltic pump. Make sure there is no dried ink on the seal or on the mesh/foam. Each halve seals 1/2 of the nozzles on the printhead
* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail.
* The capping station draws ink through the printhead, but during cleaning cycles there is a short piezo-driven jetting part as well.
* The dampers have one-way valves

I think the filters in your dampers are clogged. Based on your comments, your printhead should be good. I would replace all dampers, clean the capping station and do an initial fill.

Good luck!

I'll try to answer a few of your question based on my experience with the R3000.

* Both halves of the capping station are connected to a single peristaltic pump. Make sure there is no dried ink on the seal or on the mesh/foam. Each halve seals 1/2 of the nozzles on the printhead
* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail.
* The capping station draws ink through the printhead, but during cleaning cycles there is a short piezo-driven jetting part as well.
* The dampers have one-way valves

I think the filters in your dampers are clogged. Based on your comments, your printhead should be good. I would replace all dampers, clean the capping station and do an initial fill.

Good luck!
"* The "raw raw raw raw" sound is the capping station pump, the "buzz buzz buzz" sound is the ink pressurization system driven by a different pump. I don't know how this one works in detail."
Ahhhhh. I think you helped me to understand how what appears to be a one-way valve against the ink path flow may be gated. As described in the original post, I replaced the original ink delivery with an assembly that I put on the shelf for backup. I bought the spare assembly from a company in Florida that was converting P600s to DTG. DTG, as you may know more than me, requires conversion of the p600 to a different ink delivery system with different dampers. They were selling the removed system for 40 bucks. It looked like a cheap spare part that might come in handy (the P600 was working fine at the time). I bought the assembly. I recently noticed that there is a thread on this forum about about this company and the availability of several copies of the original P600 ink assembly. In addition to including the three tanks (3 cartridge ports per tank) that the cartridge holder rests on top of, included was the back plate that conveys the ink channels to the proximal ribbon tube connector, the ribbon tubing, and the damper assembly. These parts were preassembled. Then, there was a second part that they included in the order - RTS27B05RA Rolling Pump. This part is not sold by Compass Micro, but is sold by several Chinese vendors. I have not been able to determine how this part contributes to the Ink delivery system. But, I think that I just figured it out.
When replacing the ink tanks located below the cartridge tray, there is a nipple located on the left side of the back plate that connects to a tube of the same dimensions/color of the tubing used by the capping tubing pump. The tube from the ink tank back plate dives downward toward what I simply assumed was a waste pad in case there was a major spillage in the cartridge tray. Now I see that my assumption was wrong.
You mentioned that the "buzz buzz buzz buzz" was an ink pressurization mechanism. To left side of the carriage area I can see an edge of the rolling pump assembly mentioned above. Thus, no doubt, the tube that connects to the nipple on the left side of the back plate of the ink tank assembly is not a drain tube, as I thought, but, instead is a pressurization tube. Obviously, the design can not be to pressurize the ink path with an air pump; at least not directly. The rolling air pump must compress the membrane walls of the ink channels of the back plate. Perhaps akin to a bellows or a bladder. My bet is that this air pressurization pump opens what I have observed to be a functional one-way valve. Thus, the "buzz buzz buzz buzz" must compress the back plane membrane to put positive pressure into the ink path and force ink into the dampers. That's my bet. At least, at this moment.
Summary. I have a busted P600. I just ordered a complete ink delivery assembly and a capping station assembly from Compass Micro. Plus, I have a fresh pressurization pump on hand. My bet is that one of these three parts, or all three acting as a team, paired with an ink charge, is going to fix this P600. I will instruct my executor to put the P600 in my casket. Thank you for your help.
 
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mikling

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Sometimes the initial cause is really simple when these initial issues start appearing. Is there a buildup of pigment ink on the left side of the carriage? If the P600 or 3000 exceeds three years of use. This buildup will end up manifesting itself in strange situations in inconsistent nozzle checks for no reason. All Epson printers need to be checked for buildup of solids on the left side,
The buildup causes the nozzles to be blocked when the printhead rides over the crest and gets this muck back on the underside and blocks the nozzles. For some reason this buildup is hardly addressed by Epson. Seems like built in obsolescence for the uninformed owners.
At the same time the wipers may needs to be cleaned at the same time. Buildup of sticky dirt will not allow a clean wipe on an auto windshield. So dirty wipers simply redeposit pigment solids back into the nozzles.
If there is buildup all this disassembly etc. might have been down the garden path of destruction due to disassembly and improper reassembly.
 
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RiverRat01

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Point well taken regarding the risk of tear down. Thank you. I have cleaned the left side of the carriage area on a routine basis over the years. As you no doubt know, an external waste tank does not drain this area. I have been studying the tear down for replacing the capping station. It seams that the capping assembly needs to drop down, meaning that the bottom plastic has to drop. The YouTube videos are mostly for DTG implementations. The procedure appears to be much more invasive for the unmodified P600/R3000. There is little to no information on the Internet about lifting the frame off the bottom plastic. I can't believe how difficult Epson appears to have made it to replace a "consumable." I have the service manual, but is is not much help. I will tackle replacing the capping station this weekend. For now I am watching videos and studying the service manual to try to stack the cards in my favor that I pull this off successfully.
I have cleaned the wiper. It is bent to the left and warped into a "S" along the surface to contacts the head. I could not locate a wiper without buying the capping station.
At this time, I have perfect nozzle checks for PK, LK, LLK, and nearly so for LC. Y, VLM, VM and C are all nearly dead. My initial problem was isolated to PK. I let air get into the line. I did an ink charge and the entire printing system went South. How ironic that PK is currently fine but four other channels are out. I am wondering if the four failed channels share the same side of the capping station cap.
My waste counters, at the moment, are at 90%. I am waiting until I replace (or fail to replace) the pressure pump and capping assembly before I reset the counters and do an ink charge. I also have a fresh ink delivery system, but, at this time, I don't think it is the problem. The capping station and ink delivery system are on track for delivery today. I may have bit off more than I can chew. I have been doing this kind of thing for more than 50 years. I have a chance; but no slam dunk on the first (and last) go. Thank you for commenting.
 
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