L260 light magenta intermittent dropout

[AF]

Heat related intermittent dropout of light magenta on printhead 6. Testing has determined it is not the printhead which leaves the flex cables or PCA board as suspect. As machine warms up the issue appears and resolves when the machine is cool.

Before pulling parts off, looking to see if anyone had a similar issue and if it was the cables or the board at fault. Have not ruled out ink lines but seems unlikely.

 

[MelloImagingTechnologies]

There have been problems with light magenta over the years. What are you printing with this?
If you’re having a problem with only one head- swap it out and see if problem moves.
Text me any other questions 631-520-3074
Bruce

 

[AF]

Thanks for reply. Head swaps confirmed the issue is not the printheads. Running high heat causes the channel to drop 100% (i.e. vinyl). Most likely a cold solder joint, bad cable connector or possibly electrolytic capacitor starting to go. HP only sells the flex cables as an assembly so just looking for any experience from others who had similar issues. When the machine is cooled down, or while running a low heat media, the channel comes back 100% instantly. I will be pulling parts off shortly and will check the PCA caps and cables and connections. Maybe just reseating the cables will correct the problem. HP tech had in the past replaced the flex cables and PCA for unknown reasons. Could have not done a thorough job putting things back together.

 

[AF]

Reseated flex cable to affected printhead. Noticed the PCA heatshield has a sharp edge and that edge rubs on the flex cables. If reseating cable doesn’t fix issue, will have check cable continuity. Wouldn’t be a bad idea to put tape on the cables and edge of heat shield for abrasion resistance.

 

[MelloImagingTechnologies]

Would be a better idea to replace the printer with a reliable eco solvent printer!

 

[AF]

Just documenting what I have done here so far. Since I am starting with free / cheap / easy tests here is what I have done. The issue is NOT resolved yet, but I have a new idea. The printer does not throw an error code or other alert when the LM channel stops firing on the one printhead.

1. Swapped printheads around. Problem stays with printhead slot #6 LM channel. Will continue testing different printheads to confirm without a doubt.
2. Tried new printheads. New printhead print well for 100-150 ml, then problem resurfaces. Factory ink fill in PH could be reason for 100-150 ml. Suspect air in ink line...
3. Printer cool, LM fires at start of print but then stops a short while later as things get hot. Suspect air bubble expanding and blocking 1 printhead...
4. Reseated carriage flex cable to printhead #6. Problem persists. Could still be air bubble...
5. Did visual check of Carriage PCA capacitors. None look puffed or leaking. Not ruled out but low on suspect list.
6. Did visual check of other components on Carriage PCA at 2x magnification. No smoked parts, visible corrosion or visible solder issues. Cable sockets look ok.
7. Pulled left cover to inspect ink lines at cartridges. No air visible at this end of the ink supply lines. Clean air lines are clear, no ink. No ink leaks. Suspect air in ink line at PH#6 LM port...

Since problem appears heat related, it most likely is not occurring in the areas of the machine that do not heat up. Carriage seems likely area to focus on, especially since the problem surfaced after HP tech replaced carriage. Will attempt to purge air from line tomorrow before moving on to more involved testing. I do not want to just toss parts at the machine in hopes that something will eventually fix it. Found this video of a guy with similar issue that turned out to be air in his LM line:

 

[AF]

Had some time this morning to run service diagnostics on the machine with it cooled off overnight. Checked everything, ran all tests. Everything came back clear and ok. I primed the magenta channels. Pulled the magenta heads and cleaned them up and the electrical contacts. I then did the line purge like the video above but I used a MityVac rather than syringe. Pulled a decent amount of ink through the line in question and buttoned everything back up.

Testing now. Initial PH alignment shows all ink channels firing correctly. First print had no drop out. This same print was able to replicate the dropout within the first 12-18" of media. Second test print is good. Test plot shows everything is good. I will run some vinyl (high heat) to make sure.

I recall an HP tech mentioning an issue where they were increasing the cooldown timer from 30 minutes to 2 hours to help prevent the magenta heads from getting torched as the machine cools off. I noticed that my cooldown is the stock 30 minutes. Will increase it if I can to be safe. An extra fan to blow air around the capping station would probably eliminate the cooldown issue better than just running it longer.

 

[AF]

Issue reappeared after printing for a period of time. Replaced the affected printhead. I couldn't find a way to adjust the cooldown timer, maybe it was a firmware change. Current firmware is SP-SP_12.0.0.5 but online HP has SP-SP_0-0-02.1 so not sure if that is the latest based on numbering.

 

[AF]

Took some digging, but found out that the 2.1 firmware is the newer one. Would make sense to number them in a way that avoids confusion...

Firmware installed, printing without issue so far. Hoping the extended cooldown is included in this firmware. Looks like it would be easy to add a fan to the side of the printer to circulate air over the carriage during cooldown.