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Powerbook 500 series power adapter questions

OleLila

Well-known member
I was just going to leave a few comments about the power supply for a 520c.I had obtained the computer but had no adapter and I sprung for a working adapter on ebay for 30 bucks (more than the computer cost). When I plugged it in there was an instant pop, I checked the output and the voltage was low. I plugged in again and there was another pop, then no voltage...zero. I broke into the case and started to remove old capacitors as per multiple posts on the forum here. It's incredible how on you tube these things fall right out but I am apply prolonged heat and wiggling to get them out, then having to apply flux and braid excessively to get the area cleaned up. After spending 1-2 hours and getting2 out, I started to look for replacment options and found this on this forum

from misieweke in 2009 "I was able to get my PB520 working with a 1.3A@15V power supply from a cable modem (free). I cut the connector off of the dead original power supply and wired the orange/red wires to +15V; the black wire and braid go to ground. The blue wire is not connected.IIRC the PB520 will run on any voltage from 12-18V. Don't try a higher voltage because the protection circuitry will shut down. I found this out by powering mine with an 18V solar panel that put out >18V when cold. As the solar panel heated up the voltage went down, and the PB started drawing power." 

I can verify that I am running the powerbook with a 12 volt 2 amp  adapter now...in less them than it took(me) to remove two capacitors and plus I do not have to worry about my soldering or more troubleshooting.

I do want to point out that in another post there is a picture from Armor Alley in April of 2018 which gives the incorrect pinout for the power supply (polarities are exactly reversed). I was going to post straight from the apple service manual (and what is working for me) but inexplicably, my uploading of images doesn't work right now. 

In regards to just replacing the innards of the power supply with a generic and wiring them as above. What are the disadvantage? If I used a 3 amp supply and just wired the battery and computer pins  to 3 amps, wouldn't each component just draw the amperage  needs (1.0 and 1.5 amps)? If this is true, then why does the original power supply have a 3 amp fuse and why did they take the time to put essentially 2 power supplies in the Apple branded power supply? If I cannot wire them to the same generic power supply, can I put a switch on the generic power supply that I  filp into one position to supply the computer and the other to charge the battery (only one at a time)? Will I cause an explosion of the battery or are all the electronics in the computer and intelligent battery to regulate this?

I cannot figure out why people are recapping and are not just cracking open the Apple power supply and exchanging the innards with a generic 12-18 volt adapter. 
 
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Paralel

Well-known member
Most people here are restorers and preservationists, fixing broken parts and using period correct hardware. Most would rather restore the original AC adapter to working order than just use a generic, even if it is easier.

 
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superjer2000

Well-known member
Most people here are restorers and preservationists, fixing broken parts and using period correct hardware. Most would rather restore the original AC adapter to working order than just use a generic, even if it is easier.
I don't necessarily agree with this. I want to make sure the base computer is working but I couldn't care less if the inside of an ac adapter is original.  I have two se30s and a IIci with transplanted ATX power supplies and I'm not losing any sleep. 

Anyways, I have a PowerBook 520 that I cracked the ac adapter when trying to get it open for recapping. If there's another good solution I'm all over that. Please keep us posted on progress @OleLila  

 
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