I'd like to install a new modern motherboard in a Compaq Presario 425
just for kicks and run Ubuntu. Anyway, the motherboard sort of slides
into a socket which connects it to the integrated crt monitor. Any
ideas on how I could get the schematic or just figure out those "pins"
. (It is a one-piece computer so the motherboard lacks normal pins
etc.)




--
Grendal

On Fri, 18 May 2007 04:49:27 +0100, Grendal
<Grendal.9316f8 (AT) computerbanter (DOT) com> put finger to keyboard and
composed:

The 3 RGB signals should be terminated by 75 ohm resistors inside the
monitor. A DMM should be able to find these. The H & V sync signals
would probably best be seen on an oscilloscope, or maybe a frequency
counter, or you may find a printed legend inside the monitor. Another
way to determine the pinout is to identify the graphics chip and
consult its datasheet. Still another way is to find the monitor's
vertical output chip and work backwards toward the connector.

This site ...

http://home.worldonline.dk/finth/adapters.html

.... states that the Presario 425 uses Cirrus Logic's CL-GD5420
graphics chip.

Here is the datasheet for the "CL-GD542x True Color VGA Family":
http://www.datasheetarchive.com/data...rticle=1162723

See page 12.

Pins 68 and 69 are VSYNC and HSYNC, and 77/76/75 are the RGB pins.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Thanks for all that info. It turned out that beneath a glob of glue (or
something now crystalline) I have found markings : r,g,and b in pairs -
so 6 wires are now identified. Also I see an H and V - so those are
identified. Then there is a large Black wire soldered like a ground
wire. So the only remaining unidentified wires are a brown and a white
wire (no markings) which were just above the H and the V wires. I
think the monitor is SVGA. I will go consult all your data and post
more info. My idea is to solder these to a 15 pin video plug so that
this monitor will henceforth be connected to a 1.2 ghz motherboard.
Hope that will work. Any guesses on what the remaining two wires must
be? (This is my first ever look at monitor wiring). Thanks again.




--
Grendal