cm6040mfp; blank control panel 1

[yerington]

We're having a problem with an CM6040mpf. After completing the boot process the control panel remains blank. Printing Jobs are normally executed but control panel still without any display.
We need to reboot the device after about 15min. to get the control panel operating properly.
Changing Control Panel and DC Controller did not solve.
Any Help? Thanks.

 

[hpwizzard]

I have information about two cases where a faulty memory dimm on the formatter caused the display to turn blank and unresponsive until the dimm was replaced.
In both cases, the printer seemed to be working fine hardware wise, since the ADF, ITB, Fuser, etc; make the normal movement noises as they normally do during the power ON sequence, but the display remains blank and the LEDs never turn ON and also there is zero functionality at the front panel.