Yes sfblue, right now they have a decent price listed. Sometimes they have ridiculous prices listed. It seems unpredictable at best.
Yes I have experience with americaninkjetsystems (the way my browsers break that page up on scrolling really brings back bad memories..). Also others that advertise head cleaning services. Also plenty of other options (paths, even journeys) to partake in considering printhead clog clearing (including re-fillable cleaning carts, solutions, wet paper towel techniques, all configurations of menu settings cleanings, service mode cleanings, shaking the machine, even throwing it off a cliff - which I tried once but the clogs never budged).. You will find, as did the rest of us, that none of these work. You will also find that all lines of communication go blank once you mention to these printhead cleaning websites that it's a "4900/7900/9900". I even shipped our X900 printhead to Canada where one specialist machined brackets to fit our heads to his ultrasonic cleaning machines so he could break up the clogs. Three months later our head came back as a very shiny paperweight. So far, best I know, we are on our own. But there is hope. Research is forging us ahead into a new realm of understanding. Soon enough we will have a far better grip on exactly what we are up against.
To answer your previous question, all channels are handled by the same printhead - there is just one. You fix one channel, you fix them all. Unfortunately, you break one channel, you break them all.
If you get cornered I'll change your head. Hell I came about a minute from flying to Oklahoma last week for one of our other family members. Problem was we couldn't find him a head for under two grand, so flights ended up making it not worth while. 11880s are more expensive. You challenge is your head most likely, not your pump and cap assy. Changing the pump and cap to clear a clog is like Left Eye singing about chasing waterfalls. Depending on how many prints you've run, which in your case sounds minimal, it's better to clean the pump and cap, but replace the head. My two cents anyway. The parts changing procedures are completely separate. Left side of the machine comes apart to swap the head, right side of the machine comes apart to change the pump and cap assy.
And no, your D1 serviceman will not be able to change both parts in one hour. More like three, and that's if he's on the ball.
Glad you like the story. Hesitated to tell it here.