Hi,

I just realised my iMac has a VGA port on the back of it!! (and looking around other message boards, i am not alone, i saw someone telling someone else that iMac G3's never came with VGA ports).

Apple did completly cover it up with a plastic strip. But anyway.

My LCD screen that I attached instantly mirrored the iMac's screen - no configuration require - which was great, but this is not exactly the configuration i what i want...
three questions:

1. Is it possible to make the iMac span to both displays (separate images)??
2. Can the iMac's CTR be turned off but not the pluged in LCD screen? (it defeats the purpose if both are just mirrors and they are both on and the LCD is not any benifit - even though it has a better resolution)
3. Can i independently change the resolution of the LCD screen - to its native resolution of 1280 x 1024, the iMac's CTR is 1024 x 768. Can the graphics card inside support this resolution anyway???

A note... after pluging in the LCD, the iMac doesn't seem to 'see' the new LCD, in the system profiler, and the iMac shows up as "mirroring: Off", can this be changed or does this mean it doesn't support something.

Another Note, the main reason i want to scrap the CTR is it is having horible issues... (really scary - honesty), when it hasn't been on for a little bit, when it is turned on it, the picture violently shakes around and flickers and so on... then after a few minutes (usually) it goes back to normal.

G3 iBooks were able to use an external monitor but were only able to mirror the primary display. However, a hack was developed that I used happily that allowed the extra screen to be used as additional desktop - not mirroring - that hack may work on the iMacs.

http://www.rutemoeller.com/mp/ibook/ibook_e.html

That's the Screen Spanning Doctor hack which enables extended desktops on many G3/G4 macs.

I sincerely hope it was not someone here who said that ALL CRT iMacs dont' have a VGA out. The early 66 MHz bus tray loaders and the first 100MHz bus 350MHz iMac didn't have a VGA out whereas all later models (400MHz plus) did.

None of the G3 iMacs that have an external VGA socket support anything other than screen mirroring. As a result your screen resolution will always be limited to the iMacs maximum of 1024x768. It makes no difference what resolution your external monitor will support.

Be mindful also that that some LCD's don't run happily for extended periods at 75Hz which is the CRT iMacs minimum refresh rate. My LCD, for example, will display images at higher frrequencies than its reccomended 60 Hz but will switch off to prevent damage after 15 minutes.

Finally I know nothing about disabling the internal CRT on the iMac and thereby having it detect the external monitor as the primary display. It'd make an interesting experiment.

EDIT: the screen spanning doctor hack does not work on any G3 CRT iMac.