Thank you for your quick response Eric
that's right you have to be very attentive to all the screws and especially the magnetized screwdriver is essential (on the photo below the tools I used !)
Disassembling reassembling the head took me nearly 3 hours, as my 9900 is relatively new o-rings are in good condition and remain in place
I had the shop that sells print heads on the phone yesterday (luckily I speak German!...Französisch mit einem Akzent...lol) And there seems to be no problem with them for a new head, (around 900$) if i order it I will receive it within 48 hours, in fact this store is the largest reseller for Europe, after there are also many other stores that sell print heads but mainly in Asia and in China, but that makes me a little scared!
the technician also asked me to check the cables connecting the head to the motherboard, I did it (again) and the printer display (again) : "connection error", so as i think motherboard and cables seem beings in order I must say that the German technicians are very accurate and professional compared to the French!
I also filed a complaint with Epson France, first by the way that my printer as only 82 pages printed and with Epson premium photo paper only, the head had to have a factory default
! and secondly by the fact that a manufacturer is required to supply spare parts of equipment that it sells, it seams that epson voluntarily refuse to sell parts!
So i'm ready to file a legal complaint with the help of a lawyer and an organization of Consumer Inquiries if necessary!
Regarding the procedure of ranking of the head, I am in touch with a photographer friend from spain he
had many problems with the quality of maintenance work epson, and finaly... changed the head of his Epson 9880 himself 8 months ago, without in the end entering the code ranking, he have to do several cleaning before printing of course, but the printer works fine since ... (may be my friend was lucky and bought a head ready for 9880, but there are many users who say that this is just a trick to Epson to provide work for their service maintenance!)
In fact this type of print head (ref: F191040, or x6 in asia) is mounted on several Epson models, the German dealer explained to me yesterday that "recording code heads parameters" in the computer of the printer helped it to synchronize properly...I know the operation principle of a piezo print head but somewhere it leaves me dreamy
He did not know if the given program with the 9900 allow by itself this kind of change, he said that some models have it directly in soft whith acces from the control panel and others do not, he also told me that I would find on the net a cd called epson resources,who can help me if the 9900 don't have the option, I seeks for this cd... in case!
So in summary, I do not have any problems for disassembly reassembly (I must say that my nikon d3 is much more difficult to disassemble!... ....oups !! no trouble for disassemble but to re-assemble
: see the picture of nikon dismounted below and you can cry whith me...)
But as my printer is bloqued into a fatal error I have no more access to internal programs and I do not know if it can execute any procedure of ranking...
Did you know if your 7900 authorizes by itself this procedure? if it does I think the 9900 will as well!
thank you again