We have restored several “dead” 4900’s. Unfortunately some have turned out to have a head issue, but others just some serious cleaning.
The 4900 head is sort of “spring” loaded, so it is pretty easy to dampen something and place it under the head, then use something like foam core to push the head tight. Normal procedure for us in AIS solution CLF007+ solution on paper towels and head pushed tight. We usually do this several times and the result should be a pretty colorful paper towel as ink will wick out through the nozzles. This solution is also good to put directly into the capping station. After that we do a power clean, then we run an epson nozzle exercise test (which is similar to printing one of the
cleaning pages I’ve made or others have discussed on this forum) from the Epson software. At that point we should see nozzles clearing ... if after all this we get a blank nozzle check we know something more serious is going on.
Often the nozzle check isn’t totally clear and the procedure varies depending on what we have. It it’s still pretty bad, we repeat the above procedure. Sometimes we use the solution in the capping station and it let sit overnight. Once we get a decent nozzle check we will continue to work with cleans, channel cleans, printing the exercise page etc.
One thing to watch once nozzles are firing is if you have a section that no matter what you do nothing changes. As long as you see a few nozzles appear, and maybe a few others drop, then it’s a matter of working with the head until it clears. but if you get things to a point that nothing changes at all and section of nozzles is missing, the head is probably toast.
All power cleans should be followed up by printing a page which exercises all the nozzles before printing a nozzle check. We haven’t ever had to resort to flushing the head itself, but we also use AIS CLF008P once we get most of it restored (or on printers with less serious problems), again moistening a paper towel and pushing the head down tight to it.
For me the issue seems to be the capping station seal ... it is no secret that the 4900 might be the worst printer Epson has ever made in regards to clogs and missing nozzles. There are rumors that I’ve never been able to substantiate from Epson that the capping station was revised so newer 4900’s are better at this. I also wonder if the dampers have issues, I know my 4900 required a damper changeout after only a month.