Using CRT Monitor Only

Question

I just attached my 19 inch IBM C92 CRT monitor to my iMac G3/400. The picture appears on both monitors? How can I turn off the iMac monitor, so that only the IBM is working?. The IBM monitor is far superior. Thanks, Ken.

Answer 1

With that old of a computer, the options are few.
If you can sleep just the internal display and keep the
external one on, or dim the internal and not have the
external 'mirror' every detail on the iMac's, that could
do the trick. However, 'mirror' displays is what it does.
There had been some kinds of display hacks that had
some followers (and detractors who found problems)
so that idea, to attempt to hack the display code to
have an external display do more, may not be an idea.
A screen span doctor (extended desktop) patch will
NOT work on the iMac G3 and other computers. That
was originally a hack for some portable Macs from the
website at rutemoeller.com with a workaround.
The other possible software that may work, may not on
that CRT iMac model since the graphics processor and
other items don't work the same way as newer ones.
Switch Res X: (control panel options for some Macs)
older versions: http://www.madrau.com/download/oldies/oldies.php
(The newest Switch Res X4 is for OS X newer than 10.4)
In some situations, people have tried to dim the internal display
or have it somehow 'sleep' but in the older iMac CRT G3, this
tends to make the external one mirror the internal, too. To cover
over a warm-running CRT may create a heat problem in the Mac;
so perhaps to not have the iMac were its internal display is visible
while viewing the better quality external, is about all you can do(?)
And it is very inconvenient to open the case and unplug the CRT
so only the external will work. If you were to make a hack tower
out of the iMac G3 and forgo the CRT altogether, then you could
choose any display including LCDs as the main one...
Good luck & happy computing!