HP 8550 Service Manual - Page 460

Note Note that the Print engine can operate independent of the copy module if the video IO connection on the printer is terminated. Installers have been instructed to leave the original terminator that ships with the printer on the stand behind the printer. l Printer hardware or software configuration has not changed, or the problem is not associated with any specific software. Refer customers to their software vendor for software-related problems. l If service work has been performed or parts replaced, make sure the correct adjustments have been made. l Eliminate the host computers and all items associated with it (such as drivers, applications, spoolers, etc.) as being possible causes of the problem. Process of elimination Through verification, isolate the problem to the system device. Verification step Power Display Possible problem No power The display on either the printer or the copy module is not on and showing information Solution/location of solution l Plug a device known to work into the power outlet. l Temporarily plug the printer power cable directly into the wall outlet. l Verify that the three power switches are ON. Note: The printer switch will be covered by a plastic tab. If the plastic tab is in place, the switch underneath it is ON. l Verify that the power cables are functional and connected correctly. l Verify that the circuit breaker in the copy module has not been tripped. l Verify that the power requirements for the system have been met. l If the control panel display on the printer is not working, see the HP Color LaserJet 8500/8550 Printer Family Service Manual. l If the control panel display on the copy module is not working, see wiring diagrams and system block diagrams ("Copy module" on page 178 of chapter 5) to locate and check for loose connections or failed parts. 458 Chapter 7 - Troubleshooting EN