To get into maintenance mode, press copy on the screen of the printer, then hold down the home button until you get into a black screen with The serial number of the printer, the ROM version, and some other thing I forgot. Hold down the *th button, which is blank. When you get to the keypad, quickly press *, *, * in that order on the numberpad. If done correctly, your printer will say MAINTENANCE at the top of the screen. After that, press *, *, * in that order on the numberpad. If done correctly, your printer should say uINIT*P ALL at the top of the screen. Find the keypad page with the arrow buttons on it, and use the arrows to select what color you would like to deep clean. it should say one of these codes: uINIT*P CYAN, uINIT*P YELLOW, uINIT*P MAGENTA, or uINIT*P BLACK. Select the color to deep clean, and press Mono Start on the screen. The printer will now begin cleaning only the cartridge you selected, and it will clean it deeper than it usually does with all of them. Once it's done with that, go in and manually print a quality check page. If the color affected is back, you've successfully fixed the issue! Congratulations!