I work with a small community center that
has a computer lab, and we were
donated an iMac that works but has a
dead monitor. Because we don't have a
lot of space but would love to have
another G3, we would like to drop the
motherboard, hard drive, and CD drive
into an older Mac case that we have lying
around, either a PPC case or a Centris
610 case.

Because space is the issue, and if this
doesn't work we can't use the machine
anyway, we took, the motherboard, and
components out of the shell.

So my questions are as follows:
What are the compatability issues with
power supplies? ( I read on the iMac rack
mount project that they are close to a
standard PC power supply)

Can the modem be removed from the
motherboard?

Can the iMac CPU fan be reatched, or do
we need a new fan to be powered from
new supply?

Any help would be greatly appreciated

What iMac is it? That'll make a LOT of difference in how much work it will take to make it work without a monitor.

p

I really think you'd have been better off
leaving the iMac's guts in the original
case--I can't imagine it would take that
much more space to sit a working
external monitor next to the iMac, but then
again, you know your lab's space
requirements better than I do. I'm unsure
how successful your retrofit is going to
be--getting an iMac to work is rather iffy
once you've removed its innards. You say
the iMac has a fan, so that makes it a
tray-loading iMac. The power supply
board (on the left side as you face the
rear of the iMac) is iMac-specific--you're
not going to find something in the PC
world like it, though the iMac rack-mount
project you refer to (can you cite a URL?)
sounds interesting--maybe someone's
worked out a way to substitute a PC
power supply. Whatever the video
problem the iMac is having (analog/video
board, on the right side of the iMac, as
you face the rear of the iMac; or picture
tube trouble), the logic board won't
function unless the analog board is
plugged into it. It might be possible to run
the iMac without the picture tube being
plugged into the circuit board on the neck
of the tube, but then again, something
weird might happen to the analog/video
board if you try to run the iMac without the
picture tube plugged in. So you see that
most everything in the iMac as it was
originally assembled, is required to get
the iMac to run. I've seen black screen
iMacs about equally divided between
logic board problems and analog/video
board problems, so before you go much
farther, you should reassemble the iMac
and plug an external monitor into it to see
if the logic board is the culprit--if it's not
putting out video, then the project is moot.
I'd advise reassembling the iMac, but
unplugging the 15-pin video cable from
the video port on the rear of the mass
storage assembly, and plugging an
external monitor into the video port; if you
have a 15-pin Mac monitor, it will plug in
directly, but if you have a monitor with a
VGA (3-row) video plug, you'll need a little
adapter to allow you to plug it into the
iMac's 15 pin video port.

The modem card is plugged into the
underside of the logic board, and it's
removable, but since it's iMac-specific,
and you might want to use this iMac for
modem communications, I can't figure
out why you'd want to remove it, except
possibly to use it in another tray-loading
iMac that has a bad modem.

The fan is a standard 12 volt DC fan; any
computer power supply will deliver 12
volts you can tap off of.

I really think your time would be better
spent clearing a little extra space to sit an
external monitor next to the black screen
iMac. Your success is much more
assured. Then again, projects like this
can be great learning experiences.