Are there diagnostic LEDs on an iMac emc2105?

My iMac EMc2105 recently stopped working. There is no sign of life whatsoever, light, sound, etc...

I am assuming it is a power supply issue. However before ordering parts and replacing, I am trying to diagnose the problem to ensure I do the correct repair. I have removed the front bezel to check the diagnostic LEDs. There are is only one led that I an find on the logi board. It is to the far right of the ram under the speaker. There is a hole through the speaker to view it. Are there any other LEDs on this model?