Like most I'll start by saying I have read every post, thread, comment and opinion from Jan 26 2012 when this first started until today. Taken me all of 3 weeks but worth every minute.
I myself have had over 40 of these wide format Epson printers over the past few years and that's just the X900 generation, if we included the 7800 and 7600 series then I dread to think how many we've had. Right now we have 5 x 7890 and 2 x 9890 (we have had the 7900 too but we honestly CANNOT see any visible advantage having orange and green.
Anyway, we have so many of these because of the amount of use they get, every printer prints roughly 60-80 metres of media PER DAY, so our machines don't have the issue of not being used enough. We tend not to have issues with the smaller 24" machines but we have the exact same issue over and over with the larger machines, it's ALWAYS the Light Magenta and Matte Black that block, and always in the same places too, it's about 50% of the nozzle that gets blocked rendering it almost useless.
So today after a few emails back and forth with Eric I decided to go for it and try and save myself some money. I had two goals here, firstly see If I can take apart one of the 9890, clean the head and put it back in and see what happens, if that fails then remove a head from a 7890, put that into a 9890 so then I only have to buy a new 7890 saving myself £2k ($3000) in the process.
Here's what happened, I stripped the 9890 down and got the head out.... This is what it looked like....
So after cleaning off the obvious gunk I soaked in the Red Epson cleaner I bought from Gedat for about an hour, then syringed back and forth for another 20 mins or so, I could clearly see the jets were all spraying nice underneath, all looking good.
So I let it dry for an hour and placed the head back in..... No difference whatsoever.
So I then removed it again and this time went for a more forceful technique, I figured the head is knackered anyway I may as well treat it as a learning curve. So this time I hooked it up to some tubing and at the end of it a steam cleaner, I decided on this as a few companies I spoke with had said the only way to clean and dissolve dried pigment ink is with hot water. So distilled hot water in the steamer and let it do it's thing for about 10 minutes. All looking good so head back in.... And Voila.... The head is F****d... Fatal Error.
So anyway, I expected this, now onto my second goal, try and swap heads with a smaller machine, I removed the head from a 7890 (by now I have the dismantling process down to less than 15 mins), this one looked worse than the one above (I forgot to take pics, although I did video it), so I gave it a clean up and placed it into the 9890.... Two major things happened... Firstly when I turned the printer on it worked straight away, cleaning, nozzle checks and printing, not what I expected, I thought I needed to use this servprog.exe software to register the new head but NOOOO, I did not.... Secondly the head in the 7890 had about 7-8 lines blocked that had been blocked for a long time, after cleaning the face of the head the nozzle check is PRISTINE.....
So today I learnt 3 things....
1. I can take the head out of a 7890 and put into a 9890 very easily
2. I can clean the odd line caused by blockages to the front of the head (presumed).
3. Steam cleaning doesn't work
So now I have learnt how to easily strip these things down I am going to service them myself, I am sure with the state of the head you saw above which was from a printer only 4 MONTHS OLD that after a year it will be totally covered and blockages almost a certainty so maybe we won't need to buy as many printers now??? they normally last us about 8-10 months and seeing the head I can now see why.
Another thing I found was the software servprog.exe that certain people may or may not have got hold of covers the Epson 7700, 7900, 9700 and 9900 and NOT the 7890 and 9890 so I had to buy this from a certain not be named site for $50, and I didn't even need to use it (yet).
So from now on is my larger machines get a problem, I'll be swapping out the parts from a 24" one and save a fortune.... (why is the 44" version more than twice the price of the 24" version anyway???, they share the same electronics and printhead just a bit of extra metal and plastic in the middle).
A HUGE thanks to Eric, I wouldn't have even attempted this without the video (donation to the cause on it's way now), one thing to note is the 7890 and 9890 have an extra ground wire that needs disconnecting to remove the carriage and damper assembly, connects at the top by the 3 ribbon connectors (unless I missed it in your video somehow).