HP 750c Service Manual - Page 173

Troubleshooting Tips Repair and calibrate. Cartridges fail frequently. Carriage sensor does not correctly find media edge. Drive belts wear out prematurely. Noisy carriage movement. Ink spilling. ThirdĆparty ink and offĆaxis ink systems. Troublesome plotters. After you have made a repair, consider whether any calibrations have been affected. Remove tape and align cartridges: One frequent cause of cartridge problems is that the user has forgotten to remove the tape from new cartridges. Remove the tape. Damaged encoder strip: Another frequent cause of apparent cartridge failure may be a damaged encoder strip. If the small slots on the strip are damaged, the plotter cannot position the carriage correctly during cartridge checking. Try replacing the encoder strip. Worn wipers: If the wipers in the service station are worn down, they do not properly wipe the cartridge heads. Easy to replace. Ink on roller: Excessive ink deposits on the driveĆroller surface can fool the sensor by reflecting the light. (Cleaning roller ' chapter 4.) Optical sensor incorrectly calibrated: The accuracy calibration includes calibration of the optical sensor on the carriage. You must use polyester film when performing the accuracy calibration. Otherwise the optical sensor will have problems loading some types of media. Diazo copiers: The belt may wear prematurely if the plotter is placed near a diazo copier that uses ammonia to produce blueĆline copies. The material used in the belt is very reactive to ammonia vapor. The vapor is very corrosive and can damage other parts as well. Move the plotters away from such copiers. Storing: Keep new belts in their bags with dissicant until you need to install them. This is to avoid incorrect swelling. Dirty carriage bushing: Remove aluminum or dust particles from the bushing at the back of the carriage, and from the slider path along which the bushing moves. Spittoon and ink separator: You need to replace these parts when they fill up with ink. (See ' chapter 4.) Drawer statement: HP does not support thirdĆparty inks or offĆaxis ink systems for use with any of its DesignJet series plotters or printers. If a failure or damage to such HP products is found to be directly attributed to the use of thirdĆparty inks or offĆaxis ink systems (or any other nonĆsupported HP supply or accessory), the repair will NOT be covered under HP's warranty or maintenance contract. In such cases, standard time and material charges will be applied to service the plotter or printer." Duty cycle: Plotters need increased maintenance if users do not limit use to the dutyĆcycle recommendations. (Details ' chapter 4.) C4705-90000 Troubleshooting 8-55