HP Laserjet 4345MFP Backlight on printer display does not light. Counts up the 256MB memory then HP logo (3 sizes) appears (just visible) The 3 lights keep cycling on the display. Thats it, does nothing else. It has been left overnight and continues to display the logo and cycling 3 lights. Rear DC Cont Fan is turning. No other fans or activity with machine. When ADF/scanner/mfp or hard disk are disconnected it does recognise this and throws an error and asks for reboot. I have tried cold reset, nvram init. and hard disk init. but no difference. Your thoughts?

41.3 UNEXPECTED SIZE IN TRA 2

I recently worked on an HP LJ M4345MFP with the following problems: the display was functional, but had no backlight - the blooming logo continued to animate and lights continued to cycle, but the start-up process would not move past 6/5 "E" - and the machine would not perform a printer engine test. Tried replacing the formatter, the DC controller, and the SMPS to no avail. The resolution ended up being the engine power supply (which, unfortunately is a very involved disassembly/reassembly).

Memory DIMMs come in various flavors 1)CB420A = 32MB, 2)CB421A = 64MB, 3)CB422A = 128MB, and 4)CB423A = 256MB

When the memory counts up when turning mfp on, hold down the 6 button until all three lights on left of panel light up, then using the 3 button to scroll go to COLD RESET and touch 6 button to select. If that doesnt fix ya then you may need a hard disk drive

Ensure that you have the error message correctly written down, then go to the HP Web Site and ask them about this error, specifically in conjunction with that specific printer or all-in-one device. HP can help you find out why you are having problems.

the total page count cannot be reset, if you wish to reset consumable counts replace relevant consumable. thanks

Hi patricia_kin:
Hope this helps.

Cold reset
A cold reset unlocks menus that have been previously locked and resets all control-panel menu
items to the factory defaults. A cold reset does not clear the values in the service menu, such as the
serial number and the page counts.
NOTE Before performing a cold reset, print a menu map and a configuration page. See
Information pages. Use the information on these pages to reset customer-specific settings.
CAUTION All HP Jetdirect settings are also reset. Be sure to print a configuration page
before performing a cold reset. Make note of the IP address that is listed on the Jetdirect
configuration page. You will need to restore the IP address after performing a cold reset. See
Configuring and verifying an IP address.
To perform a cold reset
1 Turn the MFP off and then on.
2 When the memory count appears on the control-panel display, press and hold 6 until all three
LEDs flash once and then stay on. This might take up to 20 seconds.
3 Press 3 four times until COLD RESET appears on the control-panel display.
4 Press 6 one time. The MFP continues its initialization sequence.

To reset the maintenance-kit counter
1 Turn the MFP off and then on.
2 When the memory count appears on the control-panel display, press and hold 6 until all three
LEDs flash once and then stay on. (This might take up to 20 seconds.)
3 Release 6 and then press 3.
4 Press 6 to select NEW MAINTENANCE KIT.
5 The MFP completes its initialization sequence. The maintenance-kit counter is automatically reset.

Try the following steps to reinitialize the HDD:

1 Turn the printer off.
2 Turn the printer on.
3 Press and hold PAUSE/RESUME (LJ 9500) or START (LJ 9500mfp) on the control panel during the
memory count.
4 Hold PAUSE/RESUME (LJ 9500) or START (LJ 9500mfp) down until all three error lights illuminate
steadily.
5 Press (the 5 button on the MFP) until INITIALIZE DISKS appears on the display panel.
6 Press (the 6 button on the MFP).
7 The printer begins initializing the disk (this might take a moment). The control panel displays the
HP event logo and eventually displays READY.