My printer won't print yellow even when I replace the cartridge.

Desperate measures!

I have a PIXMA MP 750 and months ago my yellow ink stopped printing. I was only able to use the printer for black and white printing. Every once in awhile I would try multiple deep cleans, new ink cartridges, etc. etc. I talked to the very unhelpful folks at Canon who suggested a new print head ($70), but they couldn't guarantee this would actually work. They really thought it would be best just to buy a new printer.

Although I was feeling bad about adding yet another cheap printer to the landfill I'd pretty much decided to get a new printer. As a last resort I decided to use a suggestion I came across (at pcuser.com) to run hot water through the print head. It was easy to remove the print head (check your manual). I propped the head up in my dish drainer and ran hot water straight from the tap first through the end with the little circular parts and then through the end with the metal strips. I eventually used boiling water from the kettle.

As I poured water through one end I started to see yellow ink coming though the other end so I figured the ink had dried in the head. I kept pouring water through (from both ends) until the water ran clear. I dried the print head, put it back in with the cartridges and VOILA! after MONTHS without yellow ink it's working beautifully again!

If you've tried everything else and feel desperate enough to buy a new printer you might want to try this and report back.