Instructables

DVI to VGA Conversion on a Budget

I didn't make this into an Instructable because my wife is visiting Minnesota and took the digital camera with her. If anyone wants to build this and photograph their process, just include me as a collaborator and I'll be happy... :) I just acquired a new (used) video card for my Mac. Unfortunately, it has a ADC (Apple Display Connector) and a DVI (Digital Video Interface). While the card is capable of driving two displays, I only had a DVI-VGA adapter and ADC-VGA adapters run $50-100US! I decided that I'd just have to figure out how to wire my own adapter and run it to an unused PCI plate. The following schematic is a DVI-VGA adapter. I've included the pins that would be used for the equivalent points on an ADC connector. I just finished wiring an ADC connector to a VGA connector on another plate. It works perfectly! I hope this saves someone else a few bucks... Vegas

Picture of DVI to VGA Conversion on a Budget
fadil5 years ago
lasvegas: hello its a note i wont to tell you about it ,my vedio projector dvi output is have 30pin not 24 what can i do for this proplem help me please ..
LasVegas (author)  fadil5 years ago
Ah! You had me confused. You cannot convert VGA to DVI-D. A display with a DVI input port expects digital video and VGA only supplies analog. Reversing the above schematic would only work if the display accepted DVI-A or DVI-I, but if it did, it would also supply a VGA in port.
LasVegas - great service you are providing here. Trying to save money here as well - on my mac laptop is a DVI out - I feel confident doing the wiring - need to convert to RGB RCA composite wires. I purchased a non powered adapter which did not convert the signal correctly or my television was not compatible. Any thoughts on DVI to composite/RCA conversion for a non HDTV?
LasVegas (author)  jpaureli5 years ago
If you have a monitor/TV with RGB input it actually appears as RGBHV or RGsB. If there are H (Horz Sync) & V (Vert Sync) ports, you can drive it with 5 RCA cables to the like signals in the DVI/I connector. If, on the other hand, the display expects a "Sync on Green" signal, you will have to build/find a circuit to combine the G, H and V signals into a composite signal. My HD TV has the ability to accept RGB in the Component ports using the audio ports as H and V. LasVegas

Your TV does that?! Omg! I just tried it with mine... But no go. It's not using the L & R audio as a proxy for H and V. :(

LasVegas (author)  Koppenhoefer3 months ago

Yes. It was a feature of the early Mitsubishi rear projection HD TVs.

LasVegas

Hello, I have purchased an adapter (non-Apple) and have tried using it as follows: Mac Pro -> DVI-I cable -> adapter -> VGA input of monitor (So, the adapter is DVI-A female to VGA male.) I have verified the pin connections through the adapter, but in using the adapter, my video screen is blank. Is it possible that Apple's DVI-I port has a non-standard pin-out? By the way, if I use Apple's DVI-VGA adapter at the computer, then run a VGA cable from the adapter to the monitor, the monitor works fine. Thanks. Robert
I found the problem: my DVI cable is not, in fact, a DVI-I cable, as it lacks the four pins that would have surrounded the ground blade, and those four pins carry the analog signals for colour. Sorry for the false alarm.

hi

I am having a HP laptop with HDMI port only i have HDMI-DVI converter with c1,c2,c3,c4,c5 at the dvi port.

can i use the above circuit to covert the DVI to VGA ?

i think the that the signal from HDMI to DVI would be digital and it would not worlk with the above diagram.

please help

smodi13 years ago
Hi everybody,

I am looking for DIY solution for DVI to TV - out convertor.
I want to connect my PC to TV with full screen out put without any loss.
please share the complete info about how to make DVI to Tv - out convertor at modi.sachin@gmail.com

Your help will be really appreciated.


g.rocket smodi12 years ago
http://pinouts.ru/VideoCables/hdmi_dvi_cable_pinout.shtml

this website details a full pinout for dvi-d to hdmi (they use the same format)

hope it helps
If it's DVI to baseband composite video, forget about it. There is no easy way, other than ordering an expensive box from the kind of store that TV stations shop at. Just get a new or used video card that has the appropriate kind of TV output.
LasVegas (author)  bassbindevil2 years ago
DVI-I (as used above) does not require any expensive conversion to get a composite signal. If your computer has DVI-D (the four pins surrounding the flat ground pin are missing) then the above adapter wouldn't work anyway.
LasVegas (author)  smodi13 years ago
This entirely depends on your TV. There are five possible inputs on your TV:

Composite: This signal is normally not available on a DVI connector. It would require a conversion circuit.

Component: Sorry, the data is not available for Component and would require a hardware converter.

RGAHV: Most TVs that accept Component will also accept RGB on the same terminals. You should be able to use the VGA adapter here, a VGA to BNC cable and 5 BNC to RCA addapters. Of course, you could always build your own cable. :)

VGA: Just use the given adapter.

HDMI: HDMI is pretty much the same as DVI-D with audio inlcluded. You can purchase a DVI to HDMI very inexpensively from your local Frys, Bestbuy or similar stores.
smodi1 LasVegas3 years ago
Thanks for your reply. So i have to use DVI>VGA>Tv - out technic, i want to put my video on cable TV network and for that it require to connect graphic card tv out to modulator so i need only component tv out . unfortunately in india mostly shops or computer dealers don't know what to use for what. and readymade VGA to Component adapter are fail to provide me TV - out, now i need help to build my own VGA to Component conversion adapter with reverse current protection.
Red.Dwarf2 years ago
To turn off a monitor using the VGA connector you can disconnect the sync lines which forces the monitor to power saving mode just like a PC would do.

I was experimenting with this as I wanted to be able to turn off my PC monitor while having a 2nd display active. Windows doesn't allow independent power saving for displays, therefore I had to find a way of doing it as I didn't want my PC display on. It's the same when using a TV out on a graphics card, if the PC monitor goes into standby, the TV display goes black.

See the following page at the bottom.
http://www.epanorama.net/documents/pc/vga_bd15.html
Thanks !

For your Help I will try this..

GOD BLESS..
jun
junbata2 years ago
HI everybody ! Hope you can help me.

Which pin i will going to Isolate from the D-SUB connector. 15 pins.
To be able to force to Blank the screen by using remote relay.. (Without damaging the Monitor).

I understand that i can put relay to power source of MOnitor to CUT OFF or FORCE to STOPPED. the monitor. But, this is not good for the unit.

So, my plan is to control only the signal. by d-SUB pins. One of 15 PINS.
My Question which one ?

Thanks a lot..
vga-pinout.jpg
spanagiotis3 years ago
Hi everybody!!!!!

I have a monitor (FORMAC 2010) that has an ADC connector and i want to connect it to my PC who has a card with DVI and VGA !!!I just want the signal not the usb from the monitor!!!!is it possible to work just by connecting the pins from the ADC to a DVI male connector? The monitor also has an external power supply on the cable (15V ) so i believe that i don't have to connect the 25V of the connector!!!

I'd be greatful is someone could help me!!!!
Thanks a lot guys!!!!!
goldivox4 years ago
I'm looking to use an Apple 17" Studio Display (with ADC, full sized connector) into my PC's DVI only video port - will these 11 ADC pinouts run to a DVI plug (according to your diagram) get me there? It's hard to justify $99 for Apple's DVI to ADC adapter for this oldish Apple Display that's probably not worth the price of that adapter.
steakbread4 years ago
Is there a way to wire a dvi-d to a component?
LasVegas (author)  steakbread4 years ago
 Component, while analog, is not RGB. Without a conversion circuit, a TV that supports RGB in place of the Component inputs (mine does) or a VGA port, you would not be able to feed Component from an ADC port.
 I think he doesn't have ADC, he is just asking for DVI toComponent, conversion. Some TV-s lack RGB input  so synchronized video signal is required as S-video or only yellow video chinch.
Think I saw somewhere scheme to get RGB  signal from ADC connector on Apple computer and use it to give it to TV , just to use as second display if there is lack of the original ADC monitor. It's simple and just need to short the detection pins so the signal should be released.
LasVegas (author)  pichaga9334 years ago
 There is also no Component signals present on DVI. DVI-A and DVI-I contain RGBHV signals which can be processed by some HD sets or can be converted with a hardware circuit. It can not be achieved with a simple adaptor.
 Why does everyone love dvi so much anyways? Maclovers?

Btw, how long have you been back LasVegas, I just kinda found my  way out of the woods myself. I remember you just sorta..... disappeared
LasVegas (author)  Punkguyta4 years ago
 What's wrong with DVI? Currently, it's the digital video standard. You can't get 1080P without it. Also, what's wrong with Mac Lovers? I happen to be one. Windows has always seemed to be designed to make its users feel stupid because the way you think it should do something isn't the way MS does it. It's MS's way or no way.

I only come back to respond to legitimate questions. Contributing just isn't worth it when other's can freely steal your material and call it their own and questions pertain to my psoriasis or my wife's less than teen-aged hands rather than the topic in question. When the kids are no longer in control, I'll contribute again.
Crikey - you're still here. Nice to know you are still around and alive etc.

Best wishes and regards

L
LasVegas (author)  lemonie4 years ago
 Thanks! Love your new (young) avatar. :)
 I can't argue that one bit.
nope,

DVI-D port runs only digital signals

Component ports runs only analog signals 
Read more aboute pinouts and ports here:
http://pinouts.ru/

BUT it is possible to wire

VGA port to Component port with  home made adapter herw you are a scheme:
http://www.tkk.fi/Misc/Electronics/circuits/vga2tv/circuit.html

Thats why is theoretically possible to use the same adapter from the link above to wire :
DVI-I port(DVI-I, digital and analog) to a Component port(analog only), just have to wire dthe analog pins from the DVI-I adapter to those meant for the VGA port, 
All of these are awaliable at:
http://pinouts.ru/search.php

but you have to read carefully..

I wish you good luck. ;)
 you for responding. I know the fromat of the wires, I read though, that there is analog composite and digital composite. I am trying to run a digital signal from my geforce 8800gt's dvi rather that the s-video adapted to composite to my cathode ray HDTV Toshiba 34hf81c. I know there is a digital board inside the set. the deal is i keep seeing that composite can also be digital.....
I google digital composite and there is info on both analog and digital, so what am i missing?

Sorry. I meant component not composite.
LasVegas (author)  steakbread4 years ago
Component is always analog. 

 

Component (YPbPr) requires three analog signals consisting of Y (luma or brightness), Pb (Blue minus Luma) and Pr (Red minus Luma). Green is derived through the above three signals. Horizontal and Vertical signals are also sent through the Y signal in much the same way as Composite

 

RGB is simply the Red, Green and Blue analog signals. Horizontal and Vertical signals are usually sent separately through H and V lines but sometimes they're sent with the Green signal as Composite.

 

DVI-I and DVI-A always supply RGB-HV and cannot directly drive Component.

 

If your HD-TV has HDMI, you can easily adapt DVI-I or DVI-D since they are electrically compatible. At current prices, you would be best off, purchasing an adapter or cable.

 

If you're interested in building your own RGB/HV to Component Encoder, you can visit this site. There you will find schematics and kits.

 

Good-luck!

 

LasVegas

LasVegas (author)  LasVegas4 years ago
 Sorry... The above link only supplies the Encoder pre-assembled.
(removed by author or community request)
LasVegas (author)  steakbread4 years ago
 I'm confused… What kind of converter box? YPbPr is already Component and is Analog. The digital signals from HDMI are the same as that from DVI-D or DVI-I.
LasVegas (author)  LasVegas4 years ago
 Ah! Okay… I understand. No you wouldn't see a difference except, perhaps in the format the video is sent through the Component lines. HDMI/DVI is capable of displaying 1080p (1920x1080), 1080i (interlaced - 540 lines per scan), 720p (1280x720) or 720i(interlaced - 360 lines per scan), where Component can display 1080i, 720p or 720i. Depending on what the device is sending will effect the display quality. On my TV, 720p tends to be a lot darker than 1080i, but about the same quality.
would I notice any difference between Ypbpr straight from the blue ray
and hdmi to a converter box since it is converting it to analog?
pichaga9334 years ago
Hi, LAS Vegas.

Im doing a conversion of Apple Cinema Display 17" LCD with ADC port to a PC with DVI.. and separate power supply for the monitor

I red all your instructions and on many other sites
and I'm planning to do this:
pics.data.bg/zoom/albums/2777c7ffa4e0dfb59394539c82844cea
http://pics.data.bg/zoom/albums/2777c7ffa4e0dfb59394539c82844cea

As I see it, you are GURU and almost  God in these tematics so I will ask some questions:

1. Where to connect 13pin(Soft Power) from the ADC connector( or what type of signal should I give to this pin so the monitor should start up, how to power up the monitor

2. On the DVI connector-14 pin, there is 5volts that are supplied by the Video card, I dont see the logic to conect them to the 5 volts given by  ADC-3pin?, you said that to one of the others before, but it seems not logical?

I tought to conect : Pin3 from ADC to pin 16 on DVI on the card, and LEAVE pin 14 on the DVI on the v.card NOT CONNECTED to nothing.

3. Why to connect pin11 from ADC to pin 15 of DVI.  First is groud for 25v, second is ground for 5v from the external supply for the monitor it seems not logical too.
Can't I get the needet ground for pin15 of the DVI from pin 23 on ADC: it is grond for 5 volts ?


  
LasVegas (author)  pichaga9334 years ago
 1 - You'll have to experiment with this. It would either be a pull-up or pull-down trigger. I would connect a 100K or so resistor from 13 to both +5 and ground and try pulling it up to 5v or down to ground to see which performs the action.

2 - Normally an LED supply line will be +5 volts at a relatively low current (probably less than 300mA). All it's used for on a monitor is to tell the monitor that a source is connected. Pin 3 is sufficient for the purpose.

3 - Any DC return is going to be connected to the same ground in the computer's power supply. The USB return is likely going to be through current limiting (500mA limit on USB) circuitry. It would probably be sufficient to use either though.
About 1 (Soft Power). 
I have another idea, as I red from other forums ADC doesn't power until it is connected to original APPLEComputer and if is disconnected and reconnected to the ADC-DVI hacked cable with PC on it  ,the monitor is still ON and the hack is OK until you power it down then the monitor can't be powered on again with the PC.

So the  assumption is that :The ADC monitor is powering ON ,by  software signal from the USB. I can get old USB Apple Keyboard with powering ON key on it ,that  runs a separate circuit for this key and delivers it to the USB connector so it should supply the POWER ON SOFTWARE-signal and if I connect it on the ADC monitors USB hub connector  the problem should be resolved.

-Some people tried to ground the 13 Soft Power signal from the ADC monitor results in - "no success". 

-They tried also to gave 5 volts with resistor on the way , again -doesn't work.
thats why I asked you but it is  still a problem ...

So there is no need to try it out again...

PS. There are no drivers for the located on the ADC monitor USB hub so there is no way to be recognized on the PC.

I think that the Soft Power- pin 13 on the ADC is to power the computer through  a key / touch button on the monitor or so i will leave it  unconnected.

When i tried it ALL  I will write again.

 Hi,
I have got an apple display with ADC connector and a PC with DVI video card and I was looking forward to build an adapter on my own; did you manage to finish your? Do you have a working pinout? 
I have got a keyboard to do the test you were describing so I'll probably give it a try as soon as I get some spare time.
Best

pichaga9334 years ago
 
prehodadc_1.jpg
dadadata5 years ago
<strong>The Apple docs link for DVI and Apple digital video outputs has moved. This is the information no one seems to have ... you want a "29-pin" generic DVI-VGA adaptor, and not "24-pin."<br /> <br /> Cost is about $4.<br /> <br /> Figure 3-7 </strong>DVI connector<br /> <img alt="DVI connector" height="70" src="http://developer.apple.com/legacy/mac/library/documentation/Hardware/Developer_Notes/Macintosh_CPUs-G5/PowerMacG5/Art/050378001703_07.gif" width="219" /><br /> <br /> <br /> <table border="0" cellpadding="5" cellspacing="0" class="graybox"> <strong>Table 3-9 </strong>Signals on the DVI connector <tbody> <tr> <th align="left" bgcolor="#cccccc" scope="col" style="font-weight: bold;"> <p>Pin</p> </th> <th align="left" bgcolor="#cccccc" scope="col" style="font-weight: bold;"> <p>Signal name</p> </th> <th align="left" bgcolor="#cccccc" scope="col" style="font-weight: bold;"> <p>Pin</p> </th> <th align="left" bgcolor="#cccccc" scope="col" style="font-weight: bold;"> <p>Signal name</p> </th> </tr> <tr> <td scope="row"> <p>1</p> </td> <td> <p>TMDS Data2–</p> </td> <td> <p>13</p> </td> <td> <p>TMDS Data3+</p> </td> </tr> <tr> <td scope="row"> <p>2</p> </td> <td> <p>TMDS Data2+</p> </td> <td> <p>14</p> </td> <td> <p>+5V Power</p> </td> </tr> <tr> <td scope="row"> <p>3</p> </td> <td> <p>TMDS Data2/4 Shield</p> </td> <td> <p>15</p> </td> <td> <p>Ground for +5V Power</p> </td> </tr> <tr> <td scope="row"> <p>4</p> </td> <td> <p>TMDS Data4–</p> </td> <td> <p>16</p> </td> <td> <p>Hot Plug Detect</p> </td> </tr> <tr> <td scope="row"> <p>5</p> </td> <td> <p>TMDS Data4+</p> </td> <td> <p>17</p> </td> <td> <p>TMDS Data0–</p> </td> </tr> <tr> <td scope="row"> <p>6</p> </td> <td> <p>DDC Clock</p> </td> <td> <p>18</p> </td> <td> <p>TMDS Data0+</p> </td> </tr> <tr> <td scope="row"> <p>7</p> </td> <td> <p>DDC Data</p> </td> <td> <p>19</p> </td> <td> <p>TMDS Data0/5 Shield</p> </td> </tr> <tr> <td scope="row"> <p>8</p> </td> <td> <p>Analog vertical sync</p> </td> <td> <p>20</p> </td> <td> <p>TMDS Data5–</p> </td> </tr> <tr> <td scope="row"> <p>9</p> </td> <td> <p>TMDS Data1–</p> </td> <td> <p>21</p> </td> <td> <p>TMDS Data5+</p> </td> </tr> <tr> <td scope="row"> <p>10</p> </td> <td> <p>TMDS Data1+</p> </td> <td> <p>22</p> </td> <td> <p>TMDS Clock Shield</p> </td> </tr> <tr> <td scope="row"> <p>11</p> </td> <td> <p>TMDS Data1/3 Shield</p> </td> <td> <p>23</p> </td> <td> <p>TMDS Clock+</p> </td> </tr> <tr> <td scope="row"> <p>12</p> </td> <td> <p>TMDS Data3–</p> </td> <td> <p>24</p> </td> <td> <p>TMDS Clock–</p> </td> </tr> <tr> <td scope="row"> <p>C1</p> </td> <td> <p>Analog red</p> </td> <td> <p>C4</p> </td> <td> <p>Analog horizontal sync</p> </td> </tr> <tr> <td scope="row"> <p>C2</p> </td> <td> <p>Analog green</p> </td> <td> <p>C5</p> </td> <td> <p>Analog ground (analog R, G, B return)</p> </td> </tr> <tr> <td scope="row"> <p>C3</p> </td> <td> <p>Analog blue</p> </td> <td> </td> <td> </td> </tr> </tbody> </table> <br /> <table border="0" cellpadding="5" cellspacing="0" class="graybox"> <br /> </table>
LasVegas (author)  dadadata5 years ago
My instructable was to convert an Apple Display Connector (ADC) to VGA, not a DVI port. A bit more pricy for an adapter.
Yes, you're right. I was searching for pinouts on the GeForce/Apple cards in late G4s and G5s. Teh Guggle found your instructable with the link to the Tech Note on pinouts from someone else who commented. I just thought I'd add in what I found with respect to the fact that it moved, and then had a little fun pasting in the pinouts for the DVI port, since you can easily wind up buying the wrong adaptor for DVI-VGA.

Apple's been wonderfully creative over the years with video I/O connectors. Sigh. Nearly as much fun as the RAM Stick Follies.
:O HE LIVES 

Welcome back!
fadil5 years ago
please can you geve me your e mail
fadil5 years ago
thank you very much i go to connect it and tell you what happend next time sory for my brokin language because i was arabic
fadil5 years ago
hello lasvegas: the pin 9 in vga cable is is not found then when i connect the the 14,16 in dvi to it. help me please with my thanks : sltaoon@yahoo.com
LasVegas (author)  fadil5 years ago
If the vga port has no pin 9, then the device has no use for the +5v supply from the source. It isn't always required. Pin 14 (+5v) still needs to be jumpered to pin 16 (Hot-Plug) to tell the source that a connector is in place.
fadil5 years ago
the pin 9 is not found in vga cable
fadil5 years ago
las vegas :is this degram work to connect pc to all vedio projector please answer
LasVegas (author)  fadil5 years ago
You should have no problem using this to connect to a Video Projector. This would be the equivalent to a DVI to VGA cable or adapter.
fadil5 years ago
thanks for this great jop you was save my vedio projector..thanks again..
Punkguyta6 years ago
Have you seen this? You could add a serial port with your vga connector :p
Hello LasVegas, I am playing around with a DVI cable, my intentions are to make a ADC to DVI adapter by splitting the end of a DVI cable and rearranging the pins. I have an old G4 and I'm trying to connect 2 DVI monitors to it. I don't care about the 24V or the USB of the ADC, I just would like to have 2 monitors working. Can this be done and do you know if it would work?
LasVegas (author)  johnjohnjohn6 years ago
No problem. If you compare the pinout of the ADC port, all of the lines if a DVI-I port are there. Since you're only interested in the DVI-D signals, do a Google search for the DVI-D pinout and match the lines with those on the ADC port. You may have a hard time finding a Male ADC connector, so your solution may have to be comparable to mine where the lines are drawn directly from the card's port and run to an empty slot plate. with a female DVI connector.
I got a little confused with what you said, but I want to show you my little project here http://picasaweb.google.com/Inti540i/DVIADCProject?authkey=rb-IzAAuAzc
I have found this pin layout apparently for a G5 ADC port but I'm assuming that all ADCs are the same http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-G5/PowerMacG5/3Input-Output/chapter_4_section_12.html I have traced the pins and found out what you see on my last picture.
I believe I have pins 1,2,3,9,10,11,17,18,19,6,7 worked out since according to the diagram the have exact name match. My dilemma now is with 14,15,16,22,23,24 because I do not see a exact name match on the diagram and I am not sure how many of those are needed.
Do I make sense? :)
LasVegas (author)  johnjohnjohn6 years ago
Yes. Frustrating though... Isn't it? I suggest the following. We may need to make adjustments later if it doesn't work, but these should work. 8 - Analog Vertical Sync - Unnecessary for digital monitor (is pin 10 though) 14 - +5V Power -Use LED power (3) 15 Ground -Use 25V Return (11) 16 Hot Plug Detect - USE LED Power (3) 22 TMDS Clock Shield - Use Clock Return (20) 23 TMDS Clock+ - Use Clock+ (29) 24 TMDS Clock- - Use Clock- (30)
fij6 years ago
I'm looking to reverse this schematic to connect a vga port to an adc monitor. Apart from supplying the +25v for the monitor power it prettty much looks liike the same diagram. Am I being too simplistic in assuming the apple monitor supports analogue at all? Failing that the dvi spec looks very similar to adc, is it just a bit of pin twisting?
LasVegas (author)  fij6 years ago
No. An ADC monitor requires the digital information available from the ADC port. You can get those signals from a DVI-D or DVI-I port, but not from a VGA port. Of course, the 24V power line would have to be supplied externally but would be easier and safer using the DrBott DV-ator adapter.
I meant to say a DVI to ADC adapter by modifying the pins on one end of DVI cable to be able to plug it in directly to the ADC port of the video card.
gyromild7 years ago
The rest of the pins are pretty self explanatory, but what the two VGA DDC pins are for? DDC Clock (15) and DDC Dat (12)..
LasVegas (author)  gyromild7 years ago
They follow the DDC2 protocol to communicate to the computer the monitor's specs. Pin 9 supplies the +5v for this function. Note also that all three color wires should be twisted clockwise with their respective return line.
You're too damn smart...I'm beginning to think that my suspicions about you are correct.
LasVegas (author)  Weissensteinburg7 years ago
Alright... I admit it... I'm from the planet Zantique. Just don't tell anybody!
o rly? That wasn't even one of my guesses. I figured you were either"

  • The guy from "The Shooter"
  • A Robot