Chosen Solution
Hi, those first iMac had the VGA / DB15F connctor wich could be use like a monitor with macmini or classica PC. Is possible not powering the mainboard (hard disk and fan) and use just it, for a better silence? Wich cable I must not connect? Thanks!
The VGA connection is an output connection (dual display) so you can use a projector (think class room). You require the main logic board (and the HD) to drive the signal for the display so I don’t see were you are heading here. Are you thinking of trying to make this display connect to another system? If so it won’t work.
I’m leaving this answer here for posterity. I have done this by removing the entire motherboard and drive assembly. you need to tap together the power on line on the power supply. These will be the brown and purple wires at the end of the atx connection. You can wire a switch to them so you can turn the monitor on and off, otherwise it will be always on if it is plugged in.
