Hi Nic,
I've never used resetting the PRAM to fix a USB port issue before on a
Mac -- only used it for audio sound repairs. However, the part about
removing a battery and holding down the power button with the battery
out (to discharge the capacitor) is something I've had to do before
with an IBM ThinkPad laptop to reset electronic components. So that
may work in your case, too.
HTH
Cheers,
Esther
Nicolai Svendsen wrote:
Hi Esther,
Thank you. I'll try this. Resetting the PRAM has been tried before,
but I'm supposing holding down the power button when battery is
removed is some sort of cycle? I'll add it to resetting the PRAM
again and let you know how it works out.
Regards,
Nic
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On May 7, 2010, at 2:18 AM, Esther wrote:
Hi Nic,
I'll cc this to the viphone list, since the last part of this post
is about USB power usage and charging for the iPhone, iPod Touch
and iPad. I'm not sure I qualify with respect to knowing a lot
about hardware, USB devices, and electricity, but I'll try to
answer your question, although I've never had OS X shut a device
down with a message that it was drawing too much power. However, I
did just make a recent trip where I had to troubleshoot one of the
USB ports of a MacBook. Devices that were plugged into that port
didn't work properly: printer cables wouldn't relay signals to the
attached peripheral, iPods would not be recognized by iTunes, and a
plugged in mouse was evidently powered (lit up), but not enough to
register clicks on the machine. All these devices worked correctly
when plugged into the other USB port. Power cycling with restart
and repairing permissions didn't help. (I only tried the
permissions repair because the Software Update had just been run to
install a security update before the problem behavior.) What did
work was resetting the PRAM, which apparently restored the USB port
to its full power. If the source of your problem is not the aging
of your headphones but the USB current support from your computer,
this fix might help. I'll give you the instructions I received from
Apple's Tech Support, since they're slightly different from what is
in the Knowledge Base article.
1. Power down the computer and remove the battery from the MacBook.
(On my model you need to get a thick coin, like a U.S. nickel, to
insert in the slot of the lock for the battery, and give it a
quarter turn clockwise to rotate it into the unlock position so the
side of the battery near the lock will pop up, and so that the
battery can be removed.)
2. With the battery removed, hold down the power button for at
least 12 seconds.
3. Replace the battery. (On my model, you insert the side near the
left edge of the laptop so that it engages, and then swing the
other end so that it slots into the lock position. Then you use
the coin to turn the slotted lock a quarter turn counter-clockwise
to lock again.)
4. Hold down the Command, Option, P, and R keys while you power on
your laptop. I press down the Command, Option, and R keys with my
left hand (little finger on the Option key, ring finger on the
Command key, and either middle or index finger on the R key). I
press the thumb of my right hand on the P key and push down on the
power button with the middle finger of my right hand.
5. You need to keep the Command, Option, P, and R keys pressed for
at least 3 start-up chimes before releasing them in order to reset
the PRAM.
6. Log in as usual and check your USB port connections.
This fixed all the problems with the USB ports. I think, because
the mouse was being powered, but not enough to register clicks with
the system, that full power wasn't going to one of the USB ports.
I'll point you to the Apple Knowledge Base article on "Apple
Computers: Powering a peripheral through USB":
http://support.apple.com/kb/HT4049
Computer USB 2 ports are supposed to be rated for 500 mAH. That's
less than the 1000 mAH you'll get from an AC outlet (in the U.S.)
with a USB charger for the iPhone or iPod Touch, which is why
charging your device on the computer's USB port is slower, and
which is also why the earlier iPods and iPhones could charge from
FireWire connectors that didn't have the same limitation. Apple
shifted the standard connector for its iPods and iPhones to USB2
because most Windows computers didn't have FireWire (a.k.a. IEEE
1394) ports. This is the source of some of the battery charging
error messages that are seen with some iPhone cases -- all devices
are now supposed to use chargers that adhere to the more limited
current capacities for the USB2 standard. This is also the reason
why some 3rd party batteries will take a long time to charge an
iPhone if they only supply 500 mAH of current. I suspect that this
is also why some cases, like the Mophie JuicePack Air, require you
to discharge the secondary battery before draining the main iPhone
battery for maximum charging use, since most batteries do not
maintain power regulation as they discharge and may go out of the
regulation specs. (This is of interest to me as an iPod Touch
owner, since Mophie just came out with a JuicePack Air for the iPod
Touch -- however, it appears to disable the internal speaker
whether or not the earbuds are plugged in when the iPod is in the
case, and also appears to disable use of the volume, start/stop,
and voice control functions of the headset earbuds that com with
the iPod Touch 3GS if they are used while the device is in the
Mophie JuicePack Air case. This is based on user comments for this
product at the Apple Online Store.) Incidentally, the 10 W Power
Adapter for the iPad will charge iPods and iPhones, as well as the
iPad (which draws 2100 mAH). However, the iPad will apparently not
charge (even slowly) off the USB ports of non-Mac computers, and
when connected to a Mac's USB port (not through a keyboard USB
port, and not through a hub), may even give a message that the
device is not charging (although, if you wait long enough, it will
charge).
From the same Apple Knowledge Base article that I linked above,
here's the information about USB charging on newer Intel Macs:
"On some newer Intel-based Macs, such as the MacBook (13-inch, Late
2007), when a device requiring more than 5V and 500mA is connected,
the port with that device connected to it becomes a high-powered
port capable of offering up to 1100 mA at 5 V. That port will
continue to operate as a high-powered port until the device is
removed. "
That same Knowledge Base article (about USB charging) is referenced
in a link in the Knowledge Base Article about "iPad: Charging the
battery":
http://support.apple.com/kb/HT4060
HTH
Cheers,
Esther
Nicolai Svendsen wrote:
Hi guys,
So, I'm looking for someone here who knows a lot about hardware,
specifically on the Mac-side and someone who knows a lot in
particular about USB-devices. Oh, and electricity, perhaps.
Here's the deal.
I've got a Skype Wireless Freetalk Headset, the old model. I've
been using it for a while with no issues at all. Eventually, my
Mac would disable the device because it said it was drawing too
much power and had to be disabled.
The headset setup consist of a round-shaped small box with one
button to turn off the receiver completely, and to pair it
properly to the receiver and the headset. On this box there are
two buttons, one extending to the plug of a USB and the other
extending to a small, round plug which plugs into the right side
of the headset for charging. Both of these aforementioned wires
both extend away from the round box. When I get the message above
in a dialog box, the headset promptly turns off because there is
no signal being received from the USB port as it becomes disabled,
and when touching the wire charging the headset, it becomes
boiling hot. The USB wire feels fine, but all the way from the
point from which the wire to the charger extends, to the plug that
goes into the headset for charging, becomes incredibly hot and
almost impossible to touch.
My question to those knowing about this type of issue is this: Why
would this happen after a year or so of using this headset just
fine? Is it because the wire is broken? If that is the case, why
could I use it for a couple of hours prior to this happening
today, regardless of twisted the wire became?
Thanks, and I'd be grateful for any advice.
Regards,
Nic
Mobile Me: nic2...@me.com
Skype: Kvalme
MSN Messenger: nico...@home3.gvdnet.dk
AIM: cincinster
yahoo Messenger: cin368
Facebook Profile
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