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A Mac issue that has me stumped: anyone else ever had this?
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A Mac issue that has me stumped: anyone else ever had this?

DJMark 10:57 AM - 19 December, 2010
DJ-ed in a place I've never played in before. TTM57SL, and a pair of Stanton straight-arm turntables in individual cases all sitting on two tables. Super simple, plugged in and everything worked fine for about 4.5 hours. Just ScratchLive, no video.

End of the night, quit SSL and shut down the computer. Seconds later I hear the startup chime, and the computer's on and booted again...all by itself.

Unplugged all cords (power and USB)...shut it down again...same thing.

It wasn't the power-button sticking, cause once on it stayed on fine...and the power button worked as expected.

Wound up carrying it home in sleep mode (it would stay in that mode OK).

I got the computer home...and now it will shut off and stay off. WTF!

The only possibility I can think of: I had the computer sitting on a (metal) Stanton laptop stand. The bottom was tucked in under one of the turntables. Power to the setup looked kind of sketchy (don't know if stuff was really grounded or not, lots of long extension cord between the wall outlet and the DJ setup. Maybe there was some current leakage to the Mac's aluminum case through the stand? Not even sure if that would cause spontaneous powering-on, and I'm obviously not up for experimenting with feeding live voltage to my MBP's case!

Anyone have any other ideas?
Laz219 11:24 AM - 19 December, 2010
No messages saying the laptop couldn't shut down because a program was keeping it open?
DJMark 11:48 AM - 19 December, 2010
Quote:
No messages saying the laptop couldn't shut down because a program was keeping it open?


No. It was shutting down in a completely normal way...but then immediately powering itself back on. It did that maybe a half-dozen times. Never seen anything like it before. Now at home, it's acting normal (staying off when shut down).

Sure wish I had thought of the possibility of the metal laptop stand somehow carrying current to the computer's case before leaving there...
Laz219 11:58 AM - 19 December, 2010
I can't imagine that would be the issue, I'd be expecting more some process was preventing a full shutdown.
I'll have a look into it tomorrow, theres a few relevant looking links here though:
www.google.com.au
DJMark 12:27 PM - 19 December, 2010
I watched it 5-6 times...shutdown was happening completely (desktop faded to blue, then screen power off)...and then the startup chime was heard a few seconds later. There were no delays of any kind.

I've seen situations in the past where some process delayed/prevented shutdown...and in those cases the screen did NOT get powered off nor did the computer reboot itself. Instead, it would just sit there for a long time (or infinitely) on a blue screen, sometimes with the little grey "wheel of dots" turning in the middle of the screen.

I also don't see anything in the logs that would indicate any process was preventing shutdown. (Also strange, of course, that any such problem would magically clear itself up...that isn't my typical experience in cases where something goes wrong with a Mac OS installation).

I'm curious enough that I may pay the place a visit again just to see if the issue repeats itself at the venue. If I do that, I'll also bring a multimeter to check for power leakage from the turntable underside. (Hell, maybe I had the laptop stand touching a frayed power cord or something crazy like that).
DJMark 12:29 PM - 19 December, 2010
I watched it 5-6 times...shutdown was happening completely (desktop faded to blue, then screen power off)...and then the startup chime was heard a few seconds later. There were no delays of any kind.

I've seen situations in the past where some process delayed/prevented shutdown...and in those cases the screen did NOT get powered off nor did the computer reboot itself. Instead, it would just sit there for a long time (or infinitely) on a blue screen, sometimes with the little grey "wheel of dots" turning in the middle of the screen.

I also don't see anything in the logs that would indicate any process was preventing shutdown. (Also strange, of course, that any such problem would magically clear itself up...that isn't my typical experience in cases where something goes wrong with a Mac OS installation).

I'm curious enough that I may pay the place a visit again just to see if the issue repeats itself at the venue. If I do that, I'll also bring a multimeter to check for power leakage from the turntable underside. (Hell, maybe I had the laptop stand touching a frayed power cord or something crazy like that).
BERTO 2:34 PM - 19 December, 2010
do you run caffeine? or something similar perhaps this may have kept computer on
DJ TOGTFO 3:48 PM - 19 December, 2010
Check your battery cycles. I had a similar issue when my battery was starting to go haywire
sixxx 11:29 PM - 19 December, 2010
I haven't had this issue but a few times I turn my computer on and the chime keepa going gading away on the 2nd, 3rd, 4th time like an echo.

The other issue i've seen is turning on my computer and the green light to the webcam is on. No issues whatsoever playing throughout the night though.
DJMark 1:02 AM - 20 December, 2010
Quote:
I haven't had this issue but a few times I turn my computer on and the chime keepa going gading away on the 2nd, 3rd, 4th time like an echo.

The other issue i've seen is turning on my computer and the green light to the webcam is on. No issues whatsoever playing throughout the night though.


I've never seen (heard) that first thing, but I have seen a couple 2008-era plastic MacBooks that had the green webcam light come on for no apparent reason (and with similar results as you...it doesn't seem to disrupt anything else including SSL).
DJMark 1:05 AM - 20 December, 2010
Quote:
do you run caffeine? or something similar perhaps this may have kept computer on


I don't run Caffeine or anything similar, I just have the standard power-management settings all maxxed.
DJMark 1:14 AM - 20 December, 2010
Quote:
Check your battery cycles. I had a similar issue when my battery was starting to go haywire


Battery has a grand total of 6 cycles, and shows "normal" health in System Profiler. I've had this computer since April...rarely run it off the battery.

Charge Information:
Charge remaining (mAh): 12716
Fully charged: Yes
Charging: No
Full charge capacity (mAh): 13025
Health Information:
Cycle count: 6
Condition: Normal
Battery Installed: Yes
Amperage (mA): 0
Voltage (mV): 8296

The computer is still acting normal at home, so unless I see the symptoms I was at the club last night re-appear at home or elsewhere I'm pretty much left with the theory about electric current somehow getting into the laptop stand at the club and causing what I saw there.
DJJorel 2:03 AM - 20 December, 2010
Maybe there was a heat issue with the Macbook at the time? I'm taking a shot in the dark...but that might be another thing you might want to explore.
DJMark 6:40 AM - 20 December, 2010
Quote:
Maybe there was a heat issue with the Macbook at the time? I'm taking a shot in the dark...but that might be another thing you might want to explore.


Hmm..if it was overheating, I'd expect to have seen other symptoms as well...and I'd also expect that if the overheating was really extreme that the computer would go off (by itself) and stay off.

Anyway I'm sure that wasn't it, because I keep SMCFanControl running and have the fans cranked, and I keep an eye on the menu-bar readout of temperature when I'm playing as well. And this was just SSL with audio, no video running (so my 17" i7 MBP was not being taxed at all).
Corex 7:03 AM - 20 December, 2010
Dude, you should definitely do some full cycles on your battery every once in a while. I rarely take mine off the charger but I do it too – keeps the battery in good condition.
DJMark 7:47 AM - 20 December, 2010
Quote:
Dude, you should definitely do some full cycles on your battery every once in a while. I rarely take mine off the charger but I do it too – keeps the battery in good condition.


You are no doubt correct...and that's really the one "maintenance" type thing on my computers that I *don't* do regularly. Mostly because it's very time-consuming now (with the newer high-capacity batteries) and because in 5+ years of using Mac laptops I so far haven't seen any negative effects.

But...if that problem comes up again somewhere else besides the place I was playing last night, the battery would probably be my first suspect for trouble.