Macbook won't start after being connected to a powered USB hub

Globesearch · Jan 28, 2007

Hi there.
I connected a powered 4-port USB hub to my macbook and it stopped working. Then I discovered that the power adapter for the hub was a 12 volt adapter.

When I start the Macbook it spins up for a second and then dies. At the same time the screen briefly flashes on - then nothing.

Have I damaged something by connecting an over-powered USB hub?
Is there a remedy for this, such as some form of reset, without having to send it to Apple to replace cooked parts?

Thanks.
Globesearch

neye:

NanoBite · Jan 28, 2007

Globesearch said:
Hi there.
I connected a powered 4-port USB hub to my macbook and it stopped working. Then I discovered that the power adapter for the hub was a 12 volt adapter.

When I start the Macbook it spins up for a second and then dies. At the same time the screen briefly flashes on - then nothing.

Have I damaged something by connecting an over-powered USB hub?
Is there a remedy for this, such as some form of reset, without having to send it to Apple to replace cooked parts?

Thanks.
Globesearchneye:

G'day Globesearch & welcome to Mac-Forums.

I'm sorry I can't give you a definite answer but you really need to work through the troubleshooting steps:

Basic OS X TroubleShooting

Let us know how it goes or if you need further help.

Globesearch · Jan 28, 2007

Hi Marty and thanks for your reply.
I've tried the process in your suggestions, but the macbook won't do anything beyond a short spin of the HD and a quick flash of the screen. It then stops with a weird little squawk and then nothing.

I really think I've cooked something.

Any further thoughts?

Thanks
Peter.

NanoBite · Jan 28, 2007

Sounds grim ... I suppose the recommended Adaptor is less than half what you sent through your MacBook?

So you reset the Open Firmware and zapped the PRAM ... Have you tried booting from your Install CD/DVD?

Globesearch · Jan 28, 2007

Well, I think the hub was supposed to operate on about 5 Volts and 500mA, but I fired it up with an adapter which pumped out 12 volts and about 1 amp.

Unfortunately, it won't start for me to be able to do anything with PRAM or firmware - and of course it won't accept the startup DVD.

cazabam · Jan 28, 2007

I'm not sure how you could cook the machine by connecting it to a powered hub. The power from the hub's supply goes to the peripherals, not back to the host machine. If the hub came with a 12V supply, that's what it's meant to have

A couple of things to try (assuming you haven't already) is to plug it in with the power brick and press and hold the power button until you hear a long beep. This should let you get as far as hardware diagnostics, at least. Other than that, call AppleCare.

Globesearch · Jan 28, 2007

Hi Cazabam,
I gave that a try, but once again, it just did the same thing as before and died again.

Could the original attempt have caused a short circuit somewhere?

Globesearch · Jan 28, 2007

Thanks to all the kind folks with the suggestions for my problem. The machine was under warranty, so it's now with an approved repairer.
Thanks again.