HP Laserjet 4345mfp after memory count finishes control panel goes blank(display is working but all black) nothing else happens. I've already replaced formatter, dc controller and engine power supply, any suggestions?

You can try to go in the service menu.
You can find this in the administration menu, go all the way down and you will see "service".
You need to insert the service code : 11434506
From there you can reset the maintenance count i guess.

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?

After printing 215,000 pages, the MFP alerts you to order a maintenance kit. The message can be
temporarily cleared for approximately 10,000 pages by using the CLEAR MAINTENANCE
MESSAGE item on the RESETS submenu. When the page count reaches 225,000, you can no
longer clear the message and you must install the maintenance kit. To check the number of pages
that the MFP has printed since new maintenance-kit components were installed, print either a
configuration page or a supplies-status page
the maintenance kit is Fusing element , pickup rolls for all trays, and transfer corona
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.

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

Perform a cold reset

1. Turn the printer on.
2. Watch the control panel.
3. When the memory starts counting, press and hold the green (Select) button. Continue to hold Select button until all three Control Panel LED's are illuminated and on solid.
4. Release the (Select) button.
5. The control panel will display SELECT LANGUAGE .
6. Press (Down Arrow) button until control panel displays COLD RESET .
7. Press (Select). The printer will perform a cold reset and then continue its power-on sequence.

The only way to reset the total page count back to zero is from the service mode. Link for service code.
http://www.printertechs.com/tech/pin-servicemenu.php


Link for user guide, menu map under contol panel will show where service mode is.


http://www2.bvu.edu/departments/businessservices/infoservices/2fix/documents/manuals/lj4345userguide.pdf

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

BLANK or BLACK?, if it's Black, clean the SCANNER GLASS.

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.