Thank you guys for your suggestions.
I did not notice any cracks on the nipples when I replaced the dampers twice but to be honest I did not pay attention to and did not check them. I have just found used 4800(mine is 4880) for a good price and if I get it I will try to get the print head from 4800 and install it in mine to see if it makes any difference.
As I mention I would love to go back to original ink delivery but it seems there is no way for me to do it. If I put these valves back there will be no room for the UV lamp attached on the left side of the print head carriage. I think that is the reason why MFG has to remove valves on the left side and get the ink sucked from the top of each cartridge.
If I get a bulk system shown on the link below do you think it will help me to fix the problem?
Air Pressure Bulk Ink System for Epson 7700 9700 Printer ( Large Bottle Ink Supply System, CISS)-in Consumer Electronics on Aliexpress.com
It comes with regulated air pressure. I do not know if I can get it with 8 channels but they sell it in 4 channels configuration and I think I should be able to hook up tubing from this system to my flatbed one if their tubing diameter is different. With this system the ink will be supplied from outside of current ink system but I will keep empty ink cartridges just to get around the problem with the chips.
Any other suggestions would be much appreciated. I do not want to recycle $10 000 printer just because there are some problems with three channels. It makes very great prints straight after power cleaning and I love UV inks. I have tried solvent based printers and UV inks much better and easier in printer maintenance than solvent ones.