I have received a request for the TMDS-DVI pinout of the 20" iMac G4. Just like the other iMac G4 panels there is a TI chip which converts TMDS to LVDS, so with a DVI cable and power source the native lcd should be usable with any DVI compliant source. However, the caveat here is that I have been unable to get the native inverter to work properly. So, while there may be an image, with no backlighting - it will be very difficult to see.
That said there are work arounds:
1) Aftermarket inverters (works great, needs only 12V, 5V and ground), but I have not found one thin enough to close the case completely - but if you don't mind a little buldge, this does work fine.
2) Alternate Backlighting (LED etc)
3) Get the native inverter working:
What I've learned: It requires a 24V and 3.3V line. The Dimmer seems to work backwards of most where it requires 3.3V for maximum brightness. There is certainly a way to do this, but I have already damaged several in my attempts and I felt that even if I got it working, finding adequate power sources that would work together would be difficult. You would have to use a powersource that has a 24V line such as the native power source for the 20" or the iMac G5's. I didn't want to have to "turn on the backlights" with a separate switch. The Apple Cinema Display also uses a 24V line, so I initially thought about using its power brick. Thats when I realized that the power wiring including a brightness switch and on/off were already done for me by using the 20" apple cinema display itself. Conveniently, its the same size including thickness and weight as the iMac G4 20"s monitor and housing. This led me to my Apple Cinema Display/iMac Mod, which has exceeded expectations so far. But, I can understand the desire to get this as "genuine" as possible.
|iMac G4 20" TMDS-DVI Conversion|