I responded off list, but will copy/paste the response I sent for others to read. One important detail you included here, but not on your email is that you replaced the LM cartridge, but now your printer says "NO cartg" with the LC icon flashing. Have you been using a refill cart in the LC channel, and it's been working well until you installed the LM cart? If so, does the error change or stay the same if you reinstall the Epson LM cart you were previously using?
After reviewing your order history, I see you purchased a set of refillable carts and inks for your Epson 3880 in March of this year.
The plastic base of every 3880 reset chip should have three small plastic tabs around the side that hold it onto the cartridge. If any of these tabs are broken or bent inward, the chip will not stay secured to the cartridge, therefore not have a good connection with the Epson chip underneath, which will cause an error. Also, on the back of every reset chip, there should be three metal pins that stick out and touch the Epson chip- the three pins should be equal length for proper contact with the Epson chip. Please check the plastic base to make sure there are three plastic tabs, and if they are all in place, gently bend them outward slightly to ensure they catch and hold onto the cartridge. Also check to make sure the three metal pins are present and equal length. On the front of the chips, please check the gold contacts to make sure nothing is on the contacts that would interfere with the printer's ability to read it- if you see anything on the gold contacts, gently clean them with either an alcohol pad or pencil eraser. After checking all these things, push the reset chips back onto their corresponding cartridges and make sure they are pushed all the way onto the cart for a good connection with the Epson chip, then reinsert the cartridges into your printer and see how the printer responds.
Occasionally, a cartridge doesn’t fit perfectly into a printer, causing a cartridge error such as you’re experiencing. Most times, removing + reinserting the cartridge solves the problem, but sometimes people add a thin wedge of paper under the cartridge to push it up slightly, and a few people have reported they added a piece of folded masking tape to the front edge in the small rectangle notch in the top of the cart (where the printer latch holds the cart in place), to get a tight/good connection between the cartridge chip and printer’s chip sensor.
I hope this helps, please let me know if you have further questions or there’s anything else I can help you with.
Best regards~ Dana