i have the above printer and it reports a cartridge related problem. In trying to solve this, i cleaned the contacts of the cartridges i had as well as those on the cariage as details suggested by hp. nevertheless, i still could not get it to work. Additionally, i finally rulled out the cartridges i had and purchased new one with a hope that the old one are somehow faulty and still has not solved my problem. The problem as it is reported relates to either dirty contacts, incompatible cartridge, and or faulty ink cartridge. My cartridges are compatible, new and i'm now stanned and have run out of ideas as to what to rule out next or what to fix

Hi, may seem like a silly question but have you completely uninstalled the printer and then re-installed it? Also, how is the printer connected? Maybe you have a faulty cable...try another to test.

My printer is currently connected through parallel. i do not get an error message on my pc, but i get blinking lights (when i power it up)on the printer itself (status lights) which reports a cartridge problem. Unintalling will not help as the lights blink even when the printer is not connected to the pc.

The 840c is an old printer (by todays standards). I would have done exactly the same things as you have...clean everything in sight, check the contacts, buy new cartridges, check for jams, check the rollers and the carriage. Did you clean everything with a swab and alcohol?

yeah, that is what i used. What do you recommend now, throw in the bin?

Hehe...I probably would but let's give it a while and see if anyone else knows of a reason why this is happening