PowerBook G4 Aluminum laptops with 12 inch displays

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How to test battery and power adapter using multimeter?

Replaced DC-in and DC-to-DC boards. Have new battery and new power adapter. Powerbook will not start.

It could be the new (cheap) adapter malfunctions. Last time I tried testing one, I discovered the circular metal thing on the outside is just a shield, whose purpose is to make poking multimeter probes at the tiny separated sections of the male pin about impossible without arcing! So, how can I test the adapter with a meter?

It could be the battery. I don't know whether they ship charged at all. Maybe my old one is fine! They have a connector with six conducting slots. I don't want to damage the battery or my meter. How do I test the batteries with a meter?

It could be I messed something up installing those boards, or maybe another part is faulty. I've already spent too much on these pieces! If the adapter or battery is faulty I can exchange them. If they're both fine, I'll dismantle the laptop to check my previous repairs for damage. Or I'll give up!

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I ordered another adapter while I wait for someone to post an answer. How to test Powerbook batteries and adapters using a multimeter? Just need to know what to poke with the probes; somebody's got to know in this community! Right?


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dzturbd, here is the pinout of the power adapter.

tip not connected

tip/ring negative

ring + 24V

shield connected to negative with a .5MΩ R

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To test the battery, use a voltmeter to locate the positive and negative battery terminals and establish the polarity. Usually it is the outside (L+R) contacts that are positive and negative.Connecting the voltmeter to the outer terminals, take a 100-Ohm resistor (other values may also work), tie one end to ground, and with the other end touch each terminal while observing the voltmeter. If no voltage appears, the battery may be dead. The 100-Ohm resistor is low enough to engage a digital circuit and high enough to protect the battery against a possible electrical short. check here for more info. As for your battery pinout, depends on which PB you have. For that the last 4 digits of your serial number might come in handy.

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Still very unclear as to how to check various of the ipad air, power packs i have which function at different levels! ( but which if course they wont tell you pre purchase!!)

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dzturbd will be eternally grateful.
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