[Judge_Fire]

Oh noes, there goes the living room iMac (G5 iSight)

This morning it had shut down and become unresponsive to the power button. I did a SMU reset, but to no avail.

Then, in a Darwin award moment I plugged/unplugged the power cord a couple times and woohoo, success! Fans power up, power LED lights up and ... a familiar smell fills the air. Then rapid disconnect, contain, curse and now a trip to the repair shop. Hopefully just the power supply is busted. (Backups a plenty, so no prob there. )

I wonder if Firewire device load may have contributed to this. It has had two daisychained EyeTV boxes attached, one which requires its own power supply. After sleeping it, the power supply has emitted a high buzz for half an hour or so if these are connected. Similar observations have been called normal, simply a quality issue in Apple's choice for the power supply (stepper frequency blah something?).

Let's see what repairs reveals.

[Pao|o]

At first I thought Blendtech did a number on the new mid-2007 iMacs.

[mduell]

If the Firewire did it, then it's probably damage to the $$$ logic board instead of the power supply. Previous Macs have had issues with that happening.

[Simon]

Damn you! And I was already thinking, "How the heck did Tom Dickson manage to get a whole iMac into that blender???"

[Judge_Fire]

If the logic board is busted, Tom Dickson might just have my iMac

[ghporter]

Believe it or not, you can sometimes tell from the smell just what kind of component has died-and it's usually a resistor or circuit board substrate (two very different smells). Fortunately, it will be easy for the shop to tell what went out-it'll be nice and toasty brown and smell retched! Think good thoughts and hope for the best!

[Judge_Fire]

Logic board frizzle fry, thankfully covered by insurance and fixed now.

I'm still puzzled about the power supply's behaviour, namely the fact that it could be provoked to actually let the current through, having safely shut down the machine before. It wasn't replaced, so I'm kinda worried about its safety a bit.

[mduell]

That's not the power supply's fault (it just provides 5V to the logic board), that's the brain-dead Firewire power control logic.

[Judge_Fire]

Ok, I'm a bit slow when it comes to hardware

I had already disconnected all FireWire devices by the time smoking restart occurred, so the (possible) FireWire damage was done already earlier and the power supply had somehow auto-shutdown as a safety procedure?

[seanc]

Originally Posted by ghporter 

Believe it or not, you can sometimes tell from the smell just what kind of component has died-and it's usually a resistor or circuit board substrate (two very different smells). Fortunately, it will be easy for the shop to tell what went out-it'll be nice and toasty brown and smell retched! Think good thoughts and hope for the best!

Cringe worthy smells they are. Put a power supply into a dead PC earlier this week, hit the power button, BANG. We're unsure as to whether the motherboard took out the PSU or the PSU took out the motherboard. Either way, the motherboard is toast, blown caps all around the ATX connector area and we won't be putting that PSU into anything else.

What smell = what glenn?

As far as I'm aware, the two smells I can remember are, burning plastic/metal and an oniony/burning smell.