I bought a 7890 some months ago. I also purchased from Inkjetmall a complete set of replacement carts, a set of refill inks and also a second set of carts to use for piezoflush when needed.
Now the first Epson supplied initial cart (LK) is out of ink, so I took my brand new Inkjetmall LK cart, filled it with ink, primed it and replaced it in the correct bay in the printer. When I did, I noticed that it was pretty hard to push into the bay. After I got it in, the printer recognized it and was able to print. I had to go out of town for a few days and had my printer printing nozzle checks in my absence, just to keep it printing to avoid developing any blockages.
When I came back, the light on the control panel of the printer was flashing and the message was that no cart was installed in the LK bay. I opened the bay and pushed the new cart in a little and got it to recognize it.
The next morning, not recognized again. This time, I tried to pull the cart out to examine it and a piece of plastic (a side plate on the cart) came off from the friction of the cart in the bay. What's happening, is that the cart does not latch when pushed into the bay like the Epson carts do. It's also just a little too snug. Now, it's also come apart, as I described above. Because it doesn't latch into position, it pushes back out and then the printer says no cartridge.
I've been a good Inkjetmall customer for quite a while and trust your products, so I'm not sure why the fit is so tight and the latch doesn't catch. I put the original Epson cart back in place of it. It slid right in without undue friction and latched.
Is this unusual? Right now I've got a damaged LK cart and it wasn't working properly or fitting properly before I pulled it out for the last time.
I'm concerned, because I have two sets of brand new cartridges that I haven't used yet, except for the LK which isn't working. It cost me a lot of money to buy all that stuff in the first place. Any help/thoughts would be much appreciated.