Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 171

Problem
Blank screen
Monitor does not function
properly when used with
energy saver features
Video colors are wrong
If you encounter display problems, refer to the documentation
that came with your monitor and to the common causes and
solutions listed in the following table.
Cause
Monitor is not turned on and
the monitor light is not on.
The cable connections are not
correct.
The QuickBlank feature has
been enabled through
Computer Setup.
The energy saver feature has
been enabled.
The RGB (Red, Green, Blue)
input switch on the back of the
monitor is incorrectly set.
You are using a fixed-sync
monitor and it won't sync at the
resolution chosen.
Monitor without energy saver
capabilities is being used with
energy saver features enabled.
This indicates that either the
cabling or monitor impedance
is incorrect.
Solution
Turn on the monitor and check that
the monitor light is on.
Check the cable connection from the
monitor to the computer and to the
electrical outlet.
Run Computer Setup and disable the
QuickBlank feature.
Hit any key or type your password.
Set the monitor's RGB input switch to
75 ohms and, if there is a sync
switch, set it to External.
Be sure that the monitor can support
the selected resolution and refresh
rate.
Disable monitor energy saver feature.
1. Ensure that the Red, Green, and
Blue BNC cables are connected
to the corresponding monitor
connectors.
2. Be sure your monitor's RGB
inputs are set to 75 ohms.