2007 MacBook Pro, Short Circuit, Magsafe

[BrianBaughn]

Booted my 2007 MBP (2.2, 15") today and all was well until a few seconds after I connected the Magsafe charger. A pop, some burning smell and it's dead. The burnt smell is definitely on the IO board.

I'll probably get a $15 used IO board to see if that fixes it.

I've checked the Magsafe (unplugged) to see if the pins are shorted. I'm getting 0 ohms (no resistance) between pins 1 and 5 and also 2 and 4. Between 1 and 2 (and so forth) I'm seeing 60K ohms. Is this normal?

It's not uncommon for these IO boards to fail...I'm just wondering how to know if the charger could be at fault. It's in good shape.

 

[BrianBaughn]

My IO board is arriving today and I still haven't found any definitive info on how to verify if my Magsafe charger is faulty.

Does anyone have a suggestion?

 

[Smoothie]

The pin outs for the MagSafe are shown in this diagram.

According to Wikipedia, the adapter supplies 18.5 volts for the 15-inch MBP. Try checking the voltage between pins 2 and 4 (separately) and ground.

Edit: I just measured the voltage at those pin outs on a MagSafe power supply I have for a 13-inch MBP and it's 6.92 Volts. You can't really measure the true supplied voltage unless it's connected to the MBP, and that makes it impossible to get a probe in there to measure unless you have access to the power connection inside the machine.

 

[BrianBaughn]

With the charger unplugged, what resistance do you measure between pins 1 & 2 and pins 4 & 5?

Thanks.

 

[Smoothie]

With the charger unplugged, what resistance do you measure between pins 1 & 2 and pins 4 & 5?

Thanks.

54 kilohms for each.

 

[BrianBaughn]

54 kilohms for each.

Thanks. Looks like my charger is probably OK.

 

[BrianBaughn]

The $15 replacement IO board revived the dead 2007 MacBook Pro. The charger seems fine.