iMac not booting at all

Hi there !

I've got 3 iMac intel 17" (owned in 2007) and here is my problem on one of them.

Sometimes, it used to self shut down, without any apparent reason. Since 2 weeks now, impossible to turn it on ! No led flashing, not any sound...

I tried to change the supply cable with another iMac's one : Failed

I tried unplugging it, witing 10s, pressed the power button for 10 to reset everything, then plugged it back in, then waited again but still no life...

SO, I have 3 possible explainations :

• The power supply is dead
• The Logic Board is dead
• Both are dead

I was hoping you to help me. Is there any way to see or to test those parts (i mean with steps because i never electronically tested such an iMac). Do someone know about similar/common problems on the same model ?

I hope it to be back to life soon with his 2 brothers perfectly working...

Thanks in advance !

EDIT : I've not been able to find any diagnostic LED. These apparently are not on every macs.

The mac booted once but self shut down after 15mn. So i think That the motherboard is stil ok.

Still waiting for help !