iMac G4 Internal Video Connector Pinout/Schematic?

Posted by: kenif

iMac G4 Internal Video Connector Pinout/Schematic? - 10/13/06 11:08 AM

Hi, I have a Mini, and an LCD monitor off an iMac G4 Flowerpot... and evil ideas start to wander through my imagination...

Anybody have the pinout of the tiny little internal G4 iMac video connector?
Or a schematic of the iMac motherboard?

Help appreciated, otherwise I will have to put on my reverse-engineering hat and get all technical.
Posted by: Waragainstsleep

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 10/13/06 12:37 PM

Some LCDs have the pinouts printed their end. You might get lucky.....
Posted by: mrtotes

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/12/07 06:10 PM

I have a spare iMac G4 20" and although I don't yet have an Intel Mini I'm thinking along the same lines. 

I couldn't find any indication of the pin-outs on either end of the video cable :-(

Did you get anywhere?
Posted by: Protocol6v

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/12/07 08:29 PM

It won't work. It's discussed over at AppleFritter all the time. The panel in the G4 iMac is just plain LVDS. It will cost a minimum of $300 to get an adapter made, or a LOT of technical knowledge to do it yourself and a LOT of time. The best way to go about it would be to buy a cheap LCD VGA or DVI monitor with the same aspect ratio that will fit in the iMacs bezel and figure out how to run a DVI or VGA cable through the neck of the iMac. That is another story too, because from what I've seen, the neck is tight enough as it is.
Posted by: kenif

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/12/07 08:30 PM

I've been buried and haven't yet got back to this project, but I'm thinking it's not doable without some hairy electronics. The mini output is DVI, the iMac television is native LCD.

In other words, the mini video is a standard pinout rather like the old VGA standard only for digital.

The iMac is completely different, they do not convert to any external bus standard and the internal connector is producing only raw LCD signals. There are chips that do this but they are hairy QFPs with lots of legs and programming required. Not easy.

It might be easier to convert the old VGA analog signals on the DVI connector to the iMac LCD. There are cards that do that, but very expensive.

Will let you know if I make any progress on this.
Posted by: Protocol6v

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/12/07 08:33 PM

Just remembered the AppleFritter FAQ explaining...

http://www.applefritter.com/holygrail
Posted by: Waragainstsleep

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/13/07 11:04 AM

Running cables through the iMacs neck is almost as tricky. If you try and disassemble the neck, be seriously careful. There is a spring in it under incredible tension, and if it flies apart, it will hurt you badly. It took two of us using all our strength and weight to get one back together once, and I weigh well over 200lb on my own.
Posted by: Protocol6v

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/13/07 12:58 PM

Maybe you could use the iMacs LVDs cable as a VGA cable if you soldered a VGA connector on either end to the same pins as the other end...
Posted by: TCPMeta

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/14/07 05:29 AM

I thought the G4 iMac already had a port for a external monitor?

Heres a idea. Find out how much it would be for a OEM replacement LCD and see how much it would cost for the converter. Go with whats cheaper. If they both cost too much sell the iMac on ebay. Sadly every mac isn't hackable/modifiable. 
Posted by: Waragainstsleep

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/14/07 01:09 PM

Originally Posted By: "Protocol6v "

Maybe you could use the iMacs LVDs cable as a VGA cable if you soldered a VGA connector on either end to the same pins as the other end...


Sadly not. It really is alot more complicated than this. You need an IC to provide some IO. GPUs have non-standardized outputs, LCDs have non-standard inputs. This is not an issue for machines with built in displays, since the one is matched to the other (now I mention this, I wonder if LVDS is actually a standard, just with different ordered pinouts at one end or the other). Computers using external displays have to convert the signals into VGA or DVI standards. These are a different type of signal and hence a controller chip is required.
Having said that, the iMac already has one such controller on its board, since it has a VGA output. In theory, you could steal one from another iMac board if you were really handy with an iron, but this is no mean feat and wiring it up to yours would even tougher.....
Posted by: Protocol6v

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/14/07 02:25 PM

War, I meant instead of taking apart the neck to route a VGA cable through if he got a Reg. monitor he could use the LVDS cable that already runs through as a VGA cable.
Posted by: Waragainstsleep

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/15/07 12:59 AM

Maybe. Not sure how well it would work. You may not get a brilliant signal the other end. VGA cables are pretty well shielded if memory serves. They may well be significantly higher voltage too. That could burn out the LVDS cable if its too high.
Posted by: mrtotes

Re: iMac G4 Internal Video Connector Pinout/Schematic? - 08/20/07 01:54 PM

Oh well, it was a nice dream whilst it lasted.

Thanks

mrtotes