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

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fadil8 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)  fadil8 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)  jpaureli8 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 years ago

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


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.


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

smodi16 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.

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