Filed under: Hardware, PowerBook, Troubleshooting
On power adapters, PMUs and the new PowerBooks
As I
was using my one month old PowerBook yesterday, I was alarmed to see the charging light on the power adapter randomly
shift between orange and green. I came up empty handed after some googling and searching Apple's Support pages, so I
started plugging the adapter into other outlets in the apartment. No go; my adapter was still putting on its own little
glowstick show for me. I then decided to look up Apple's support document detailing the procedure for resetting a PowerBook's PMU (Power Management Unit),
which brings me to the first lesson I learned: Apple changed the PMU reset procedure for the most recent 15" and
17" Dual Layer SD PowerBooks, so definitely check
it out if you go down this same road.Unfortunately, a PMU reset still didn't solve my dilemma. Getting nervous, I finally decided to take advantage of Apple's insulting "90 days of complementary support" to see if they could bail me out. Fortunately, after some troubleshooting, I learned my second lesson of the day: PowerBook and iBook adapters, if left plugged into a wall for too long, might need to actually be reset. This can easily be done by unplugging both of an adapter's ends for at least 60 seconds. We didn't delve into the inner workings of these power adapters for an explanation, but I've kept one plugged into a specific outlet in my apartment for probably at least a month or two, and I guess that might be just enough to make a power adapter a little confused in the head. So kids, remember: don't be like me. Keep your power adapter happy and light-show free by unplugging it from time to time.
![TUAW [Cafepress]](http://www.blogsmithmedia.com/www.tuaw.com/media/tuaw-cafepress-promo.png)
Reader Comments (Page 1 of 1)
djones said 11:14AM on 1-07-2006
You know what happens when devices start getting too much electricity...
http://www.gotfuturama.com/Multimedia/EpisodeSounds/1ACV09/04.mp3
http://www.gotfuturama.com/Multimedia/EpisodeSounds/1ACV09/06.mp3
;)
Reply
fra said 11:20AM on 1-07-2006
Call Apple, if they give you support for free, use it.
Reply
Jon said 11:27AM on 1-07-2006
Why did it continue after you moved it around to other outlets? I call BS.
Reply
djones said 12:18PM on 1-07-2006
Why did it continue after you moved it around to other outlets?
Reading comprehension FTW. Both plugs must be detached for the adapter brick to reset. Unplugging just the wall plug over and over wouldn't do it.
Reply
skip said 1:32PM on 1-07-2006
And then there's my problem. I get a slight light show if the laptop end of the plug jiggles (green, off, green, off green, off, orange, off, ...). And then I decide to unplug it from the laptop and KERNEL PANIC.
This has happened several times in the past week. Is my adapter wearing out (the plug end) or is it the little board in the laptop itself?
(15" 1.25GHz Powerbook)
Reply
David Chartier said 4:30PM on 1-07-2006
Jon: When I was moving my adapter between outlets in the apartment, it was a quick 5-second process. From one end of a tiny apartment living room to the other, for example. For a true reset, both of the adapter's ends need to be unplugged from any source for at least 60 seconds.
Hope that clears things up.
Reply
Aaron said 4:37PM on 1-07-2006
Actually, I experience this problem only when using the power adapter that came with my new PowerBook. My older adapters can remain plugged in as long as I need them to.
What's more, unplugging the adapter from the wall always fixes the problem for me. There's never been any need to remove the power from the PowerBook, too.
Reply
Neutrino said 7:11PM on 1-07-2006
I've have similar problems when using a shredder plugged into the same extension cord as the PB. The PB is OK but the the noise from the electric motor makes the adapter stop working. Simply unplugging the adapter for a short time and plugging it back in fixes that. I don't recall unplugging the adapter from the PB.
I've also had problems with the plug getting out of shape. After two plus years I've managed to step on it a few times or accidentally yank the cord causing it to get out of round. I bought a second adapter for business trips and on that adapter I keep the plastic shipping cover on it when not using it. This is really helpful.
Reply
starwxrwx said 8:27PM on 1-07-2006
my ibook adaptor sometimes stops charging my ibook - eg one time when the power was shut off and turned back on, the ibook didnt resume charging (the power adaptor ring showed no light) and hence the ibook was out of juice when I found it :/
unplugging the AC end of the power adaptor (even momentarily) from the socket and then plugging it back in and turning it on again reset it somehow and then it worked
Reply
Eric said 9:27PM on 1-07-2006
Take a look at the metal connector on your power adapter where it plugs into the powerbook. Mine was doing this same thing and upon closer inspection the metal (outer loop of metal around the piece that is "inserted") was actually dividing vertically into 2 pieces. In other words there was a split in the metal that wasn't orginally there... I took it in and they are giving me a new adapter.
Reply
MILE said 2:51AM on 1-08-2006
By the way, does anybody know how to reset the PMU on a 2 year old 15" PowerBook G4 1,25 MHz?!? The info on Apple's site seems to refer only to other models, but I haven't found anything that works for my Book so far...
Reply
David Chartier said 11:16AM on 1-08-2006
MILE: the support document I linked actually does cover your PowerBook model, it's simply referred to with a different name in that document. Your PowerBook is also listed as "15-inch FW 800," as it was the first 15" PowerBook to feature that port.
So follow the instructions for that group of PowerBooks and you should be good to go.
Reply