I have an HP g7 Pavilion (B5Z48UA). Powering up produces nothing, no BIOS on-screen, nothing but a black screen. The computer was left operating correctly on Windows 7 overnight, to get upgrades in the wee hours. In the morning, when I awoke, the screen was black, andhas remained so. The CPU fan has been noisy, but still seems to work. The unit was a hard surface, so there should be no circulation cooling problems, unless it stopped - but it has worked so far as I know. Is there a possibility the computer went into sleep mode, and won't come out? I pressed the power key several times trying to awaken it, but got no response.
There is a possibility the system board has lost power. When the unit first powers with the battery installed and AC power is connected, the LED light comes on white for two secondsbut then turns orange even though the battery is fully charged. With the battery is installed but without AC power, this LED remains white, correctly indicating the the battery is fully charged. It seems possible that there is a short on the system board affecting this LED, or the AC power supply is not functioing correctly. This unit is very frustrating, trying to diagnose with no screen to help -- so far I am running blind.
I bought this unit as like new in the box from an independent seller, but used slightly. The warranty date is 06/08/2012.
I carefully disassembled the entire unit (per the service manual) to inspect all parts, and no obvious problems exist. It seems to me there are three possibilities: either the CPU has overheated and failed, or the screen lost power, or the power supply is causing problems. Does anyone have any idea how I can test these parts?
Thanks, N5YS