Troubleshooting Using the Power Switch LEDs to Troubleshoot In certain circumstances, the LEDs located on top of the power switch (located at the rear of the Printer) can help to troubleshoot the Printer. The LEDs can either be ON or Off and using different combinations can indicate different problems: Amber is on the Left Blue is in the center Green is on the Right Make sure you look directly at the LEDs and not at an angle. 1 When only the Amber LED is On: „ The Printer has been switched Off from the Front Panel (after having pressed the On/Off button).
„ The Power Supply Unit only delivers a 5 V "Standby"; power that is needed to restart the Printer after the Front Panel On/Off button is pressed (the Formatter/Main PCA will initiate the Printer to start). 2 When the Blue LED is On: Deliver standard "ATX" power for the Electronics Module PCAs (+12V, +5V, -5V, -12V, etc...). All the functions of the Electronics Module are fully operational (EWS, etc...). 3 When the Green LED is On: Deliver "analog" 24V and 42V to enable printing. The Printer monitors and reports different signals: PSU fan issues, 24V and 42V delivery failures (specific System Error reported pointing to PSU failure).
hp designjet 4000 series printer service manual 1-13 PSU Blue LED Status PSU Green LED Status Left LED (on Front Panel) Status Printer Status ON OFF Red (Front Panel Black) Standby (with Embedded Web Server up and running) ON OFF Green (flashing) Initializing ON ON Green Ready (but not printing) ON ON Green Printing or preparing to print OFF ON Any Not possible ON ON Red (Front Panel Black) Not possible