HP Latex 330 - Printhead issues after replacing FI Towers

[simocyz]

Hi there!
I purchased an used HP Latex 330 and after some jobs that went perfectly ok, it started to make few transparent/yellowish drops on printed media. Inspecting the printheads carriage, I found a massive ink quantity inside it.
FI Towers (HP spare part code M0E29-67109 - be careful if you want to replace all of them, only 8 towers are contained in each set!) replaced, leak gone.
Now I am facing issues with some of my printheads, that were printing perfectly good before the repair. On some of them, a whole color is missing (for example on a Cyan / Black printhead, Black is completely missing). Tried swapping it with the other printhead, the problem passed on the other slot, so I think it's not a cable/connectors fault.
I also tried the head wash with few drops of distilled water sitting on the nozzles and cleaning with a lint-free cloth, no luck.
Printhead cleaning from menu (tried several time) doesn't change the result.

There's something I can do to recover these printheads? It's happening on four of them, changing them all would be quite expensive.
Thank you!

P.S. : ink is flowing in the tubes, tried to pull it with a syringe (black, yellow and optimizer have a valve, as I don't know how to manually open it, I went trough the diagnostic menu and ran the ink refill with an attached syringe - stopped it after a while, to not waste ink, as it was coming correctly).

 

[Morten CHristensen]

Did you purge your lines through the service menu after replacing your FI towers? If not, that could be your problem, printheads probably Fubar

 

[simocyz]

Well, I purged them with a syringe pulling ink from the FI towers, probably that wasn’t enough?
This morning I tried doing it from the service menu, doing the ink tubes refill, but wastes a lot of ink (pumps for two minutes). Is there a way to do it for less time?

 

[balstestrat]

Push the syringe back, only let out as much ink as you want. In won't leak out, it's the normal pressure it operates at.

 

[simocyz]

Oh okay interesting, I thought it would make too much pressure and leak somewhere because of it. Can I make it push out only few milliliters, as far as there’s no air?
And, another thing: should I do it on both the FI towers of each colour?

 

[balstestrat]

Yes you can and if you want to do it properly you should do it on every FI. You replace FI -> air gets trapped there.
But to save some time.. people might do it only on the furthest away one.
It's not the end of the world to have a little air there.

 

[simocyz]

Okay, I think it’s better take that extra time to be sure to not screw the new printheads.
About the maintenance station, to make sure it’s not going to contaminate new printheads with Optimizer residues, what should I carefully clean? It’s only 30%, I wouldn’t throw it away if possible. Should I clean only the rubber parts with something like isopropyl alcohol or… distilled water?