dc vga hack question/monitor

[Jason Spivey]

Hello all I am new to the boards and to all this.

First i will start off I am working with with a pelican vga box, and and a sega astro city cabinet.

How exactley do I find the H&V sync from the monitor.(edit found the H&V) Near the rear of the monitor I see a harness with the r/g/b/h/v/ and ground. With the vga cable hack would I just hook up the hs to pin 13 and vs to pin 14. I read somwehre about twisting cables this is why I am con fu sed. Now with that 1 ground wire do I chain it to all the rgb ground pins.

Another question. the H&V sync wires go from the monitor to the what???



Jamma connector.

I am planning on putting jumper wires from the appropriate wires to the vga hack cable. Please I am new so be gentle with me. Also I would be wiiling to purchase a premade vga hack cable if I cannot complete this my self.


(edit) I did not find both the H&V sync dorectly on the hookup it says hsync. On the very tiny diagram that I found it says sync.

How would I go about hooking up just the sync when there are 2 pins 13/14 that require both.Do I just hook it up to the hsync and leave the vsync blank

[Jason Spivey]

OK once again I was able to stoop myself. i figured out the rgbhc. I was in the state of mind from an already made cable. i am building mine from the ground up so it threw me off.

One more question. How many ground wires am I hooking up.
ground to pins 5,6,7,8,10,11,. thank you in advance.

[Dave_K.]

All of the grounds in the VGA cable are connected together...so you only need one of them to go to your monitor or jamma connection.

I know you already figured it out, but just for anyone else reading:  If you interface directly to your arcade monitor, use H and V sync.  Horizontal on most monitors will also accept "composite sync or csync" which is both h+v tied together.  The only time I see people going this route is if they do not want to interface directly to the monitor, and instead interface to a jamma connector (which only has csync).

[Jason Spivey]

Well my first attempt was a no go very disappointing.
I plugged everything in and got a black screen with a white line going down the middle. I know I did everything correct so maybe my monitor is non compatable. When I plugged the jamma back in to the game the monitor acted like it didnt want to come on for a sec wich was unusual but I rechecked the connector then it came on. i guess that was it and my monitor still works thank god. Hmm I am very disheartened about this. Any ideas or could I have not wired it up correct.

Now for my question, I have a pelican vga box and dc's have a 16 pin layout. the wires coming out of the cord (from the back of the dc to the box)there are only 15 wires. Is there a chance I could have disconnected the wrong one. Also is it common for a vga box not to have all the wires hooked up.

http://www.gamesx.com/grafx/dricas.gif

In this pic it looks like #10 compsite sync is hooked up for there vga box. Would that be a problem for what I am doing.

Question#2 is the vga cable hack the same thing for a pc to jamma setup?

[Dave_K.]

Follow instructions here for hacking your Pelican VGA box to output 15khz for arcade monitors.

http://www.arcadecontrols.com/arcade_consoles.shtml#dc2arcade

Sounds like this is the problem, and not the cable which then goes from the vga box to your monitor.  You should use a mutlimeter (continuity test) and the gamesx diagram I have linked on that page to find which wire to cut inside the VGA box.  

How most VGA boxes work, is they ground both wire 6 and 7 resulting in a 31khz signal.  All you need to do is cut wire 6 inside the VGA box, and it will output 15khz rgbhv.  Remember when looking at the picture on gamesx, the pins of your cable will be the reverse order....and you are cutting the wire inside the VGA box (at the point where the cable inserts into the VGA pcb).

When making your cut, try to leave enough wire on either side so you can twist them together again in case you cut the wrong one.  Also its not good for your monitor to leave an imporperly synced signal on the monitor...if you don't see a picture after 5 seconds, turn off power on the dc or disconnect the cable.  Oh, one last thing, some games don't support the vga box in 15khz mode, so for testing just turn on the DC without a CD in it (so it will display the time/date/play menu....that should display fine).

[SNAAAKE]

okay if it helps..i know which wire is for the "HAIS" dreamcast vga box.

its the purple one.

100% sure of this.

and yes..all you do is cut wire 6.