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VGA out / VESA DDC?
Those last 3 pins?

New MessageVGA out / VESA DDC? (modified 0 times) Tackhead
OK, I've got my external VGA connector all set up, but three pins confuse me.

There are three pins (pin 2, pin 4, and pin 6) on the 10-pin connector that read +2.5V, +3.2V, and +5V (in no particular order). Pin 8 is like pin 10 - a GND.

I assume the three unknown pins are for VESA DDC, but which pin is which?

04-30-2000 06:47:59

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
You got it working? If so can you post detailed directions and parts needed. thanks
05-07-2000 16:36:31

New MessageRE:VGA out / VESA DDC? (modified 0 times) Tackhead
Works fine - just hook up the pins on the 10-pin motherboard VGA connector to the pins on a 15-pin VGA connector. I was just trying to figure out what the three unknown pins were; they carry voltages and are emphatically *not* grounds.

Parts required: 1 * 10-pin female 2mm-pitch IDC connector, a few inches of 2mm-pitch ribbon cable, 1 * 15-pin female high-density D-sub connector.

Pinouts were from around the original IO hack page:

Vga Port CN1
1 R
2 <<<<<< Something weird
3 G
4 <<<<<< Something weird
5 B
6 <<<<<< Something weird
7 H
8 GND
9 V
10 GND

05-08-2000 00:31:53

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
What about the other 5 pins?
you say hook a 15 pin vga connector to the 10 pin on the board, what about the other 5 pins?
05-08-2000 04:06:30

New MessageRE:VGA out / VESA DDC? (modified 0 times) Tackhead
Do a search for pinouts for the 15-pin VGA connector.

Match up the pins you can match up. Don't connect the pins you can't match up.

For better image quality, make sure you connect all GND pins on the 15-pin connector to GND.

Bonus points - if you can find one that's encapsulated in something non-conductive, consider adding a ferrite bead onto each end of the ribbon cable, and/or enclosing the ribbon cable in an insulated, shielded sheath, should also give you better quality. There's a hell of a lot of RF noise inside the IO's chassis.

I get a _bit_ of ghosting of characters on my VGA-out. My hunch is that this is due to capacitative munging of the signal down the ribbon cable and not RF interference, but it's strictly a hunch. I haven't used the IO on my monitor long enough to determine whether I'm annoyed by it or not. (I got a lot of ghosting when I only used one of the GNDs on the 15-pin connector. Grounding the rest of the GND pins helped a lot :)

05-08-2000 11:27:14

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
Ok, thanks, sounds good. I couldnt find any of the parts at local storess. Do you know where i can buy the parts online?

Thanks,

05-08-2000 15:10:23

New MessageRE:VGA out / VESA DDC? (modified 0 times) radio S
radio shack, sheez
05-09-2000 00:01:38

New MessageRE:VGA out / VESA DDC? (modified 0 times) Shane
My guess for pins 2, 4, and 6 is that perhaps they're for the VESA DDC stuff? The other pins you've isolated account for the video signal, but if the connect is VESA DDC compliant, than they're responsible for receiving (and sending?) the DDC data from your monitor.

Have you measured the voltage for a standard monitor connect to see what the voltage should be?

05-09-2000 00:48:58

New MessageRE:VGA out / VESA DDC? (modified 0 times) Shane
Oh, forgot.

The wiring diagram for a 15-pin VESA DDC connect can be found at http://www.hwb.acc.umu.se/co_VGAVesaDdc.html.

05-09-2000 00:50:24

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
I went to radio shack already, i had a list of like 10 components, they didnt have ANY of them.
05-09-2000 03:58:51

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
i forgot another thing,
would this crimper work for the job: http://www.jameco.com/cfm/viewdesc.cfm?part_num=73251
05-09-2000 04:01:38

New MessageRE:VGA out / VESA DDC? (modified 0 times) Tackhead
Shane: I put a scope on the three suspect DDC pins, and each was a solid voltage, not a waveform. I agree they're probably DDC, but I'm flummoxed by the fact that they're not all TTL-level. 2.5V? 3.2V? What's up with that? :)
05-09-2000 09:32:25

New MessageRE:VGA out / VESA DDC? (modified 0 times) Shane
Sorry, I must have been really tired when I wrote those posts.

First, the correct URL for the VESA DDC 15-pin connector is http://www.hwb.acc.umu.se/co_VGAVesaDdc.html.

According to the pin-out diagram, pin-9 of the DDC connector is supposed to be +5V, so at least that's explained. Pin-12 and pin-15 are used for the DDC (data line and clock line, respectively).

Have you tried to scope pin-12 and pin-15 of a 15-pin VESA DDC from a video card?

05-09-2000 12:41:19

New MessageRE:VGA out / VESA DDC? (modified 0 times) Jim Hearne
Maybe they have just used the spare pins as test points for testing the boards.
5, 3.2 and 2.5 volts are the same as the 2 power supply outputs and the power supply reference voltage.
Maybe CN13 is only used on the motherboard test setup, perhaps before the lcd display is connected up.

JIM

05-10-2000 09:07:03

New MessageRE:VGA out / VESA DDC? (modified 0 times) Shane
Well, I just put my cheap RadioShack multimeter up the pins 9, 12, and 15 (actually, all the others as well) of two of my video cards.

The first is a Diamond V770U (TNT2U). Pin 12 and 15 were both +3.45V. The second is a ATI Xpert128 (Rage128) card. Pin 12 and 15 were both +4.85V.

I checked both of my monitor cables as well. On my Viewsonic P815 AND Samsung 700IFT, pin 12 and 15 were both around +5V. Pin 9 was missing on both monitor cable.

I don't have a scope or anything, so I can't begin to figure out what pins 2, 4, and 6 are on the VGA out of the I-Opener. Either way, it's safe to leave them unconnected.

05-10-2000 21:56:54

New MessageRE:VGA out / VESA DDC? (modified 0 times) Mac-
Profile
Couldnt you use one of those extra wires that is +5v to connect a fan instead of using pins 9 and 10 of the serial port?
05-13-2000 10:09:44

New MessageRE:VGA out / VESA DDC? (modified 0 times) RavTon
Mac: Yep, I'm running my fan off pins 6 and 8. Its the same size as the COM2 header so you can use the same cable and just plug it in. That frees up COM2 so you don't have to split the power at that point. Works slick.

ravton@yahoo.com

05-13-2000 13:48:28

New MessageRE:VGA out / VESA DDC? (modified 0 times) i's wide open
I'm trying to impliment this, but am having trouble finding the parts. Can someone post their DigiKey part number?
06-28-2000 10:36:50

New MessageRE:VGA out / VESA DDC? (modified 0 times) boykster
DigiKey Parts:

2mm connector - 10 pin
MSA10A-ND $1.98 - no Strain relief
MSE10A-ND $2.39 - Strain relief

2mm (1mm pitch) ribbon cable - 44pin 5ft
AM44G-5-ND $3.19

15pin High Density D-sub Female
T815F-ND $2.45

gonna have to order more to make the $25.00 no surcharge order....

boykster

06-28-2000 11:39:05

New MessageRE:VGA out / VESA DDC? (modified 0 times) Tackhead
If you're using the stock heatsink, you'll want the version with *no* strain relief. And you may still want to shave away a small chunk of the heatsink to get it to fit nicely.

(The VGA-out on the IO's motherboard is _very_ close to the standoff pin, and the no-strain-relief 10-pin 2mm connector is _just_ a little bit too tall.)

One implementation is mine: "Day 5" at

\briefcase.yahoo.com/tackhead_1999

Honestly, I'm not sure I'd recommend doing it this way. With the connector epoxied to the backshell, putting the RF shield and backshell back on are kinda tricky.

If I were doing this mod over again, I'd try something like this: if you're using the unpopulated USB port, put down a 1-2mm layer of hot glue on the motherboard (for insulation), then plunk the 15-pin connector into the glue.

Then surround the thing with glue and while the glue is still soft (think "gooey", not "runny"!), throw the RF shield and backshell into place. Set it aside for 10 minutes.

The glue will "set" and hold the 15-pin connector in *exactly* the right place for the backshell. Remove the backshell and (gently!) the RF shield from the molded glue, and you're done.

I've used this technique successfully for a 40-pin IDE-out connector and two line-out jacks. I hope to get the pics of those mods up in a week or so.

06-28-2000 12:35:03

New MessageRE:VGA out / VESA DDC? (modified 0 times) i's wide open
thanks to all who've offered help in this matter.. I've built my cable, very well, I might add, but cannot get a VGA signal out of my iopener. I'm trying to get it to output to a magnavox video projector that has VGA in. I've never used the projector for this, so I'm not sure where my problems lay. Obviously I've got to do some more trouble shooting, but I thought if anyone had any suggestions, better to ask for help now.

For those of you who have gotten this up and running, was it an immediate thing, (meaning: as soon as you powered up, the video signal was output), or did you have to select CRT in the display device properties? Does LCD/CRT work concurrently? Does the LCD need to be unhooked.

Thanks for any help.

07-07-2000 14:52:00

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