Some of you here might know this :) I've got a system here where I need to
make it think that there's a monitor plugged into its VGA port even when there
isn't (long story).
Plugging a real CRT into the port even when that CRT is switched off and
unplugged from the AC supply works, so there's obviously some way of doing it.
Measuring the CRT above (switched off, unplugged from AC, and unplugged from
the device) with respect to the VGA connector's shield gives me the following
readings:
pin sig value
1 R 76ohm
2 G 76ohm
3 B 76ohm
4 NC GND
5 GND GND
6 GND GND
7 GND GND
8 GND GND
9 NC infinite resistance
10 GND GND
11 NC GND
12 DDC DAT 8.1Kohm (initially 7.6Kohm, rose at first then steadied)
13 HSYNC 4.6Kohm
14 VSYNC 4.7Kohm
15 DDC CLK 8.1Kohm (initially 7.6Kohm, rose at first then steadied)
Any suggestions? Do I just need 76ohm resistors to ground on the RGB lines
(and possibly 4.7Kohm resistors to ground on HSYNC and VSYNC)? Or is there
likely something more subtle going on that I need to incorporate into my
"fake" connector? (Given that VGA supplies no DC out, it can't be anything
too
complex!)
cheers
Jules