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Title: Building a 2 Output - 1 Input VGA Switch
Post by: Aryu Limitless on May 31, 2006, 06:43:08 AM

I'm tryting to figure out what I need to build this switchable y-cable.

If I tie all of the inputs and ground leads to the appropriate places on a PCB, can I get away with a DPDT across the input cables' common ground?

Or would it be more feasible to locate a 15-pole 2-throw switch for my dilemma?

Title: Building a 2 Output - 1 Input VGA Switch
Post by: NFG on May 31, 2006, 07:59:56 AM

You only really need six pins to switch between them. Ignore all the data lines, and connect all the ground lines to the same pin. All you need:

Rred
Green
Blue
H-Sync
V-Sync
Gnd

Title: Building a 2 Output - 1 Input VGA Switch
Post by: viletim! on May 31, 2006, 09:31:08 AM

Aryu Limitless,

You can't switch just grounds but you don't need to switch grounds...if that makes any sense.

BTW if this is for a desktop computer (high res video) then switching this way will distort the video a bit.

Title: Building a 2 Output - 1 Input VGA Switch
Post by: Aryu Limitless on June 23, 2006, 03:39:08 AM

The other question:
I'm connecting a 680x0 Mac and my Dreamcast via a BLAZE DC VGA box. I'm using a Viewsonic 21" flatscreen. My mac displays at 1024x768, the DC not-so-much.

Should I use diodes on the lines to prevent signal feeding back into the the other source when I'm only one?

(Did you get that?)

Title: Building a 2 Output - 1 Input VGA Switch
Post by: viletim! on June 23, 2006, 01:39:04 PM

I think you should buy (/borrow/steal/build or otherwise obtain :) ) an electronic VGA switchbox and use that.

Diodes can't be used in this fashon - your video is an AC signal (which, at any given microsecond, could be at anything between 1.4v and -1.4v ... or maybe something else), not a DC voltage.

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NFG Forums => RGB + Video Discussions => Topic started by: Aryu Limitless on May 31, 2006, 06:43:08 AM