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Rev A iMac G3

Mars478

Well-known member
Aren't the Monitor and computer two different sub-systems? When I took apart the iMac there was a DB-15 connector connecting to the iMac Logic Board/

 

Gorgonops

Moderator
Staff member
Aren't the Monitor and computer two different sub-systems? When I took apart the iMac there was a DB-15 connector connecting to the iMac Logic Board/
The built-in iMac monitor is very limited in the video modes it supports, and the ones it does support are "nonstandard". (It has a fixed horizontal scan rate which gets divided by larger or smaller numbers to produce the various vertical resolutions.) You could "in theory" drive it with another computer, but you'd have to custom-program appropriate video modes. Pretty sure that just 'plugging and going' via that 15 pin connector doesn't work on anything but an iMac motherboard. (Which has the appropriate video modes present in its firmware and recognizes that monitor when it's plugged in.)

What's more useful is being able to plug in a different monitor to your iMac's motherboard when the built-in one dies. ;^b

 

LCGuy

LC Doctor/Hot Rodder
I'm at uni now, and all my Macs at home, so I can't power up my iMac for confirmation, but I'm fairly sure I remember that the iMac supports these resolutions, ONLY at these refresh rates:

- 640x480 at 117 Hz

- 800x600 at 85 Hz

- 1024x768 at 75 Hz

Nothing more, nothing less. Even though the hardware could probably handle 640x480 at 67 Hz (the typical basic resolution supported by just about all beige Macs with built in video), it simply will not allow you to run the display at any combination of refresh rate/resolution other than the ones above. I've tried it and it doesn't work.

Connecting an external monitor to the iMac though, is a different story - you can connect any multisync Apple display, or with a VGA adaptor, just about any PC display, and run an external display at any resolution up to 1600x1200. :D

 

Mars478

Well-known member
Yeah those are what I see on mine...

So Can I just try it out for fun or will my iMac s'plode?

 

LCGuy

LC Doctor/Hot Rodder
You can try it, I have.... it won't hurt anything.......but it won't work either. :p

 
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