Random shut offs?

[misspaperwait]

I had a mid 2007 iMac that I've had for roughly 3 years now.

I love the thing, it runs beautifully BUT it has begun shutting off with no warning.

I'll be in the middle of something like say, watching a YouTube video or today I had a video lecture going and suddenly it's just off.

No warning or anything just a black screen.

I just clicked the power button and now came right back on like nothing happened.

I checked the console and noticed it says "cause of shut down: 0"

I've been researching a bit and it seems that might mean the power supply might be dying but I'd like to know for sure before I order a part.

Does this sound like a power supply issue? I grabbed istat pro and my temps are all good, kept an eye on them for the two hours I was on it before it clicked off so I don't think it's a heat issue.

I did run the apple hardware testing thing and it never crashed and all the hardware checked out as good so I'm hoping that's a good sign at least lol

 

[jerwin]

https://georgegarside.com/blog/macos/shutdown-causes/

0 Power disconnected. Check power supply/battery on a laptop, or the power supply for a Mac without a battery. On a laptop, the Mac should hibernate before the battery becomes so discharged it is unable to shutdown correctly, therefore if you see this shutdown cause on a laptop it may indicate a hardware issue with the battery or with the battery controller for reading the charge. Try resetting the SMC by connecting the switched off computer to power, holding ⌃control+⌥option+⇧shift and pressing power.

 

[misspaperwait]

Looking up the SMC thing it says to do that if your Mac shuts down unexpectedly and can't be turned back on, my Mac did shut off unexpectedly but you can always turn it right back on when it does.

Should I still reset SMC?

 

[chscag]

It does sound like a flaky power supply. You can probably find one on eBay but be careful not to spend too much on that dinosaur.

 

[misspaperwait]

I just like it so much haha it's been a great computer so far and runs so damn fast, the random shut offs is the only issue I've ever really had with it aside from having to swap out a hard drive early on.

I'm kind of hoping it's the power supply because I can swap that out fairly easily

 

[jerwin]

could also be a brownout-- it's summertime.

 

[misspaperwait]

Brownout, that's over heating right?

I've been keeping a close eye on my temps, the highest they've gotten today was 60C and that was the GPU diode, the CPU has been staying at around 38C, HD around 30C.

No crazy temps reported, I even checked them right after it went off being as I turned it right back on and the hottest temp was the GPU diode which was around 65C at the time

 

[jerwin]

Nope. A brownout is a drop in mains voltage. Very common in areas where electrical demand (from e.g. air conditioners) exceeds supply.

 

[maflynn]

Brownout, that's over heating right?

No, its that your computer is not getting the sufficient voltage/amperage from the wall plug. Usually this occurs the summer when everyone is consuming more electricity then there's available, i.e., everyone is running all of their air conditioners

 

[misspaperwait]

Oh lol well we don't have an air conditioner or anything to run at our house

The plug I'm using is brand new as well, older house but we had new plugs and such put in not long ago.