Matching cartridges

I used to own a Stylus 600.... then moved on to a 640. Although the cartidges had different code numbers, they were

in fact totally interchangeable between the two machines.

Then I purchased a model 810, which used totally different cartridges.

During the guarantee period it went dud on me, and Epson exchanged s succession of replacement machines, three

in all, for it; all faulty on delivery. Finally, they told me that they were going to upgrade me to a Photo 890, which I

received yesterday, and it seems to be working fine, but the cartridges have different product numbers from the 810,

although again they look identical. What I want to know is:-

a. Are the cartridges for the 810 interchangeable with the 890 cartridges ? Would fitting an 810 cartridge cash out

the software in the printer ? The cartridges has that tiny chip on the side, would that cause a problem ?

and-

b. Can anyone confirm that Epson are having problems with the 810 ? The fault on the new replacement machines

was the SAME problem with all of them, which was that when you switched on for the first time, and fitted the cartridges

supplied in the box, you could not cancel the red "ink out" light. After my second replacement, the Epson call centre

rep almost accused me of not fitting the cartridges correctly ! But after the third faulty delivery, a different rep didn't

seem surprised to hear of my troubles with the 810.

Thanks

Richard