Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

What's the polarity of a powerPC adapter plug!? Please help.

beachball doom

beachball doom

macrumors member
Original poster
Feb 1, 2016
40
8
I looked all over the internet and amazingly couldn't find this information. I have an old powerbook and I want to get some files from it. I have the plug but it has been cut off the powersupply. I think there was a reason for this but I can't remember why. Anyway, no big deal to wire the plug onto another adpater but I don't want to risk getting the polarity wrong! Is it inner negative or positive? thanks!
 
I wanted to make sure you got an answer to this because I know how important it is. I've made the mistake of mixing up power polarity at the cost of some dear equipment and a scare that probably took an hour or two off my life. Thankfully I avoided a fire.

You're right, this information is hard to find. I would have thought it available with a cursory search, but my google-fu failed me. And, searching through my trove of powerbook power adapters yielded only one that had a polarity symbol on it, and that one was an aftermarket off-brand. None of my Apple OEM bricks had one.

Here's what it looks like:

IMG_20200509_125945360.jpg

And closer:

IMG_20200509_130049752.jpg

The pictured brick will power every PowerBook G4 I have, from a TiBook to a DLSD. Assuming you can trust what's printed on that label (which I have no way of verifying), there it is. Keep in mind, this is for a G4 - you didn't say what kind of PowerBook you have, so this may be applicable or maybe not.

I'm not an electrician, I'm a dufus, so I can't tell you whether that's inner-negative/positive, or what have you. All I know is that when trying a different power adapter, polarity is one of the things that must exactly match, so I've learned to compare symbols.
 
  • Like
Reactions: YesWeCat and RogerWilco6502
Raging Dufus said:
I wanted to make sure you got an answer to this because I know how important it is. I've made the mistake of mixing up power polarity at the cost of some dear equipment and a scare that probably took an hour or two off my life. Thankfully I avoided a fire.

You're right, this information is hard to find. I would have thought it available with a cursory search, but my google-fu failed me. And, searching through my trove of powerbook power adapters yielded only one that had a polarity symbol on it, and that one was an aftermarket off-brand. None of my Apple OEM bricks had one.

Here's what it looks like:

View attachment 913523

And closer:

View attachment 913524

The pictured brick will power every PowerBook G4 I have, from a TiBook to a DLSD. Assuming you can trust what's printed on that label (which I have no way of verifying), there it is. Keep in mind, this is for a G4 - you didn't say what kind of PowerBook you have, so this may be applicable or maybe not.

I'm not an electrician, I'm a dufus, so I can't tell you whether that's inner-negative/positive, or what have you. All I know is that when trying a different power adapter, polarity is one of the things that must exactly match, so I've learned to compare symbols.
Click to expand...
That's center positive. I believe (but don't quote me on this) that any New World PowerBook can use any adapter that came with a New World PowerBook or an iBook, but I don't know for sure. IIRC, the older PowerBooks used a different size of jack, but I don't know if they are also different electrically or not. I only have an iBook G3 Dual USB and the brick that came with that, so I can't test my theories in any way.

Also, the reason why I specify New World is because, as you may know, not all PowerBook G3s are New World machines. IIRC only the Lombard and Pismo are. I know PowerBooks older than the G3 use a different connector than the newer PowerBooks, but I don't know what the G3 uses. I suspect they either switched to the newer (smaller) connector with the Lombard, but I don't know for certain.

Again, you'll want to verify all of my information, as I am not an expert on this either.
 
Thanks guys! By the way, if anyone has an ordinary multimeter you only need to put the probes across the plug head. The voltage will read +24volts or -24volts, depending on how you have the multimeter probes. So if the red probe is on the middle and it reads positive, you know the centre is positive. If the red probe is on the middle and it reads negative, you know the centre is negative. (PS: This is completely safe, 24volts is too low to get through human skin, the adapter could in theory be damaged however if you short the plug).
 
Last edited:
  • Like
Reactions: Raging Dufus and RogerWilco6502
beachball doom said:
Thanks guys! By the way, if anyone has an ordinary multimeter you only need to put the probes across the plug head. The voltage will read +24volts or -24volts, depending on how you have the multimeter probes. So if the red probe is on the middle and it reads positive, you know the centre is positive. If the red probe is on the middle and it reads negative, you know the centre is negative.
Click to expand...
No problem! That's a cool tip, thanks for sharing! :D
 
:-( Turns out that this plug isn't as simple as inner/outer. I had a look and in fact the outer and the tip don't directly connect to the power! Beneath the tip are two bands, almost like a stereo minijack. The power connects in fact to these bands. So it's more a case of base band / mid band. If someone has a plug like this they maybe could test it for me with a multimeter?
 
G4fanboy said:
I am sorry to came here to correct people. 2 12V bateries/transformers on parallel are still 12 Volts but DOUBLE the amperes. 2 bateries on series are 24 volts but with the same amperes
Click to expand...
You are completely correct. Embarrassing mistake. I meant to say series.
 
  • Like
Reactions: G4fanboy
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back