Over-tightening screws on damper unit cause of head failure on 9900?

Dear Dana, Walker, other members of the forum,

Many of you might have read my recent misfortunes with the Epson 9900 due to the exchange of the dampers unit and cleaning station by a technician here in Switzerland.

Reading the Service Manual of Epson, I read that the screws that attach the ink lines to the dampers unit should be tightened with a torque of 3±0.5kgf⋅cm.

When the technician was tightening the screws, I remember seeing him doing it with a conventional screwdriver I think, and tightening them really strong.

I just wonder whether an over-tightening of these screws can squeeze the O-rings, preventing the ink from freely flowing into the dampers and the head. If that is a possibility, I just wonder whether my head might have been dry in some nozzles, and then ulterior cleaning operations might have fried them due to overheating? I think I read something related to this on another post of a member with a 9900… ?

I am just trying to understand why and how it is possible that a normal “maintenance” replacement of pieces on my 9900 has led to having a massive boat anchor I need to throw away now. I am convinced something wrong happened there, and the repair company is not claiming itself responsible for the damage.

On a different note, this information is also important, because if I decide to change the head for a new one but the dampers were the culprit, then a second head might get damaged too…



Hi Rafael,

Sorry about your problems with the 9900.

When I replaced the Ink Selector on my 7900, I also noticed in the Service Manual that a torque screwdriver was needed for tightening the screws which secure the Ink Tubes. I decided to buy one in the correct torque range from Amazon and I’m glad I did. I found that the recommended torque setting is pretty low, which means it is probably very easy to over-tighten them if you aren’t using a torque driver. Also it is really important to use a NEW O-Ring Seal (part number 1518317) on each Ink Tube when putting things back together.

It’s hard to say if over-tightening the screws on the Ink Tubes could lead to your problems, but it is certainly possible. I believe that EPSON’s recommendation for using a torque driver must be for a good reason that is based on their experience in manufacturing the printer.

If you are comfortable doing it, I would consider getting a torque driver (make sure it has the right range of settings needed) and a set of new O-RINGs and re-doing the Ink Tube connections to the Ink Selector. You can do this without removing any covers or anything else. Only thing needed is to move the carriage to the center where you can work on it. MAKE SURE YOU DE-PRESSURIZE the system before removing the tubes (best thing is remove one of your cartridges then power down to guarantee you have no pressure in the system).

If you aren’t comfortable doing this yourself, I’d call the service tech and have him come back out with a torque driver and new O-RINGS and have them do it properly.

Will this fix your printer? Can’t really say. But it’s an easy thing to do before trashing the printer.

Good luck.

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