I've got to say Eric, this work you are doing is amazing. I'm glad there are other people out there as stubborn as I am about not paying out the ass for "dumb parts replacement" and more to the point, with just a general obsessive thirst for knowledge!
I too have had some pretty absurd experiences with epson print heads, and I am now also experiencing a clogging problem with a 9900.
My first experience with head removal was with a 4880 which was completely missing a Lk channel. (very) long story short, after all sorts of soaking and pulling solutions through the nozzles, the problem ended up being with the motherboard of the printer, and it ended up needing to be replaced. In this instance however, the tech that ended up working on it caused so much more damage to the printer before finally fixing the thing, that we didnt end up getting charged at all for the repair! A very uncommon occurrence indeed, but maybe the only case of things actually working out positively in the end that I've heard of thus far.
My next experience was a clogged yellow channel in an 11880. This one was serious. I went through every imaginable procedure for attempting to clean it, including basically disassembling the entire printer. Every day I was covered in ink, cleaning flushing boxes, puddling the head on the capping station, and eventually removing the head entirely to soak it. This is where the real trouble started. Somehow somewhere in removing the head, soaking it and replacing it, something got corrupted in the firmware. When I finally replaced the head It would give me an error about the head temperature being too high to run, but it wouldn't let me power-clean, or do anything else that would otherwise charge the head with ink to cool it off. A couple times I was able to get around this error by injecting a bit of ink manually into the top of the head, but something else remained the problem.
After weeks of fruitless messing around, eventually a tech needed to be called in (I work for a company that needed to get back up and running, so time was an issue) and of course the tech immediately wants to just replace the head. He does this, and..... nothing. Same problem-- can't charge it. After talking on the phone for hours, and coming back day in and day out he says nobody knows what this error code means (SOMEBODY knows....) and he needs to replace the main board. He replaces the board, and viola! things are back up and running. Then, for some idiotic reason, he decides to flash the new board with the settings from our old one, which brings back the corrupted data, and stops it from working again. This whole time I'm seething over the fact that they can't simply re-flash fresh information instead of replacing the whole f'ing board, since obviously its a firmware issue at this point. So FINALLY, a third main board installed, a new print head, and the tech now sitting there for about 6 hours printing auto head alignment patterns on an unnecessarily wide roll of paper, and we are back up and running.
Never did I get to find out if my soaking of the head cleared out the problem, and we ended up having to pay for a new main board as well as the head, AND the time of this tech who knew less than I did. Out of the goodness of their hearts, the repair company capped our cost at $5000. So theres that. I think a new 11880 at the time would have cost $7000. So theres my horror story-- basically, just be ridiculously careful that you have everything off and the capacitors discharged (switching the printer back on once unplugged) before you go pulling the head in and out---
My current issue is our 9900 began experiencing a nozzle deflection problem in the orange channel. A nozzle check showed all the nozzles firing, but some oranges were bent over to the right-- this was causing banding in our dark grey areas (go figure). Our company has a RIP, so my initial idea (after trying to clear this clog) was to simply set up a new printing linearization that doesn't use the orange (or green) ink. BUT of course, in my attempts to clear the orange issue first (the idea of not having a 100% working print head scared me too much to simply ignore it, lest more problems arise because of it) now i'm missing nozzles all over the place. I puddled the cap with windex, with isopropyl alcohol, with lighter fluid, and what I'm really kicking myself about now, I used a tiny bit of goo gone. I'm really thinking that last one may have contributed to my new problems, and now i'm letting it sit with windex in the caps for 5 days turned off in hopes that something miraculous may happen, but if not, it looks like I may be popping off my print head too.
Anyway, I do have a question, and forgive me if you mentioned this in detail already, but when soaking your head, what solution did you use? Have you used any of the ones from americaninkjetsystems? I was considering buying some of theirs to try out on this problem before i get too dirty from it. My real concern now is whether or not the solutions I submitted my head to somehow could have permanently damaged it (melting some plastics?) or if it was simply all the power cleanings, initial fills, and normal cleanings that caused these extra clogs.
anyway, I'm here willing to help, i'm a bit reckless (as you can no doubt tell) but I have a stubborn persistance that when paired with someone a little more levelheaded could really get us all somewhere....