Front panel?

[xilefian]

This is my first ever mod, and at the moment I have to put a screwdriver against the jumpers to make it startup, as I have no on button!

I wish to use an original power Macintosh G3 front-panel, as that is already compatible with my case, an original power Mac G3

This is the motherboard's front panel connector
http://i40.tinypic.com/zwdkj7.jpg
I touch pins 5 and 6 (Reading left to right, top to bottom) to start it up (It could be 6 and 8 though, unsure, trying to check now)

This is the G3's front panel connector
http://i42.tinypic.com/ibe4nq.jpg

I have the original G3 front panel cable that I can split to re-wire, i just don't know where to do it.

Here is a picture of what someone else has done in the same situation:
http://i39.tinypic.com/zmlfuu.jpg
Although I don't understand what it is he has done here! I'm not an electronics guy...
Although: The top button here is the On button, the left is the Reset button, the right is the Mystery "NMI" button.

[slaveofconvention]

Before you can do anything you're going to have to try to identify what the button on the mac board connects to - you'll need to work out which two pins it's connected to (either trace the tracks on the PCB or use a multimeter set to measure resistance). Basically you'll have to check the pins in pairs by touching the multimeter then pressing the button in question. If it's connected to the pins, the resistance will drop probably from 1.0 to 0.0. Then it'll simply be a matter of connecting those two pins to the two pins on the motherboard you have already identified.

As for what the other guy has done, he's simply bypassed the interface altogether by soldering the wire going to the motherboard power button pins directly to the microswitch. Not the most elegant solution, but it'll work perfectly.

What are the other buttons for? (just curious)

[xilefian]

One button is a reset, the other is a mystery button (Will need a G3 manual to find out what that does)

How do I follow the board? (I don't have a multimetre or any normal equipment)

Can I just test each connection with the board power pins until one works?

[Airbozo]

The other button may be an NMI (Non Maskable Interrupt) button that some of the MAC's did have. This is not something that is used on many desktop boards and recently very few server boards (the nmi is there just not a button to initiate it). In most cases it causes the system to stop what it is doing and service the interrupt which normally puts the system into a debug mode. In almost all cases it prevents the data in memory from being cleared so the debugger can diagnose any issues.

I have an email into a friend to verify this as he is a MAC fanatic...

EDIT: I am pretty sure I am right. See here: http://support.apple.com/kb/TA27026?viewlocale=en_US

EDIT 2: If you have the original flat cable you can find which lead does what by using a meter to see what wires get shorted by pushing the buttons.

[x88x]

How do I follow the board? (I don't have a multimetre or any normal equipment)

The quickest and best way will be to get a multimeter. You can pick up a decent quality one for pretty cheap (<$30) at Sears/Lowes/Home Depot/etc.

[Luke122]

+1 to all above. Good advice, very simple stuff to do. :)

Looking forward to more details on this build!

[Airbozo]

If you are careful you can follow the trace from each switch to it's corresponding pin on the header. Ground will more than likely be common between all switches and you can verify that by looking at the switch connections on the PCB.

It really would be easier to use a meter, but another way is to use a battery and light to check for continuity.