Backstory: In order to move my 7900 down a set of stairs, Epson recommends draining the ink and running their cleaning cartridges. These two sets of 11 cartridges costs over $2000. The fee for a tech fro come out and perform this task could run $500-600. $2600 service for a $3000 printer - crazy.
So I purchased set of empty cartridges to run the drain program myself. All good except the yellow cartridge would not be recognized.I tried resetting the chip, shimming top and sides per forum comments but no go. Plus, neither the drain nor the initial fill programs would run - so that I could drain the ink. Since I had left this until the last minute I wound up running several cleaning cycles with the 10 working empty cartridges installed and the stock yellow cartridge, which was about a quarter full. When the yellow cartridge was empty, and the other cartridges showed about a quarter down I was able to move the printer. For this I built a cardboard brace for the printer head and because the printer had to be stood on end to move it, moved it head side up since I figured ink might drain out if it were head side down.
The printer arrived at the bottom of the stairs without an apparent leak. It will be a couple of weeks before the printer reaches its final destination and I can fully test it but so far so good.
However I would still like to get a working yellow cartridge from Inkjet Mall, either a replacement or a new chip - as this seemed to work for another user.
I suggest keeping set of empty cartridges around for moving purposes.