HP ProDesk 405 G2 Microtower Maintenance And Service Manual page 91

Blank screen and the power LED flashes Red seven times, once every second, followed by a two second pause, and the computer
beeps seven times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause
System board failure (ROM detected failure prior to video).
Monitor does not function properly when used with energy saver features.
Cause
Monitor without energy saver capabilities is being used with
energy saver features enabled.
Dim characters.
Cause
The brightness and contrast controls are not set properly.
Cables are not properly connected.
Blurry video or requested resolution cannot be set.
Cause
If the graphics controller was upgraded, the correct graphics
drivers may not be loaded.
Monitor is not capable of displaying requested resolution.
Graphics card is bad.
The picture is broken up, rolls, jitters, or flashes.
Cause
The monitor connections may be incomplete or the monitor may
be incorrectly adjusted.
Monitor needs to be degaussed.
Solution
Replace the system board.
Solution
Disable monitor energy saver feature.
Solution
Adjust the monitor brightness and contrast controls.
Check that the graphics cable is securely connected to the
graphics card (if applicable) or video connector and the monitor.
Solution
Install the video drivers included in the upgrade kit.
Change requested resolution.
Replace the graphics card.
Solution
1. Be sure the monitor cable is securely connected to the
computer.
2. In a two-monitor system or if another monitor is in close
proximity, be sure the monitors are not interfering with
each other's electromagnetic field by moving them apart.
3. Fluorescent lights or fans may be too close to the monitor.
Degauss the monitor. Refer to the documentation that came with
the monitor for instructions.
Solving display problems 83