powerbook g4 400mhz clock battery - how much voltage?

[mattkime]

i'm having trouble finding out how much voltage i should expect from a powerbook g4 400mhz clock battery. i suspect that its not powering on due to a dead batt.

[The Grim Ninja]

I think I've heard around 3.2 to test at.

(I've never had all this clock battery voodoo that people post about. I guess I'm lucky.)

[BigGuynRusty]

Here is the part number.:
922-4361

BGnR

[BigGuynRusty]

Apple Tech Doc.:
http://docs.info.apple.com/article.html?artnum=11751

BGnR

[OWC Jamie]

On a 3 volt circuit, it's usually under around 1.7 volts when you (potentially)start having problems with powered memory.

I'd replace if it measures under 2.9vdc, but I wouldn't consider slightly low a problem yet.

I'm becoming more convinced that modern volatile memory circuits are more sensitive to power source 'cleanliness' than low power.
In other words 2 volts is fine, 2 volts with a 'burp' is not.
'burp' would be like when you rap your flashlight when the light output is low and you get more. Usually the contacts age, not the batteries age.

Edit: You'd be surprised how many times people replace the batteries to fix a problem when all they really had to do was clean the contacts. Sometimes easily done by spinning the battery in place.
(or taking it out and putting it back in)<--which is what replacing a good battery often accomplished.

[mattkime]

yeah, i know the part number but i'm still having trouble checking to see if mine works. voltage output anyone? 3.2 sounds good, but i'd like to find an offical source.

[mattkime]

thanks billb - i think its measuring right around 2.9. looks like i might be replacing the PMU on this machine as a guess at what is preventing power

[OWC Jamie]

If it's this battery:
http://eshop.macsales.com/Item_Specials.cfm?ID=2524&Item=NWTBAA36VPRAM

connect your voltmeter to the battery holder contacts and roll the battery in the holder.
if you see ANY fluctuation while rolling, clean the contacts. If you're under 3.0vdc the battery may not be a problem yet(now), but will be soon.

Edit: if you've already removed the battery and put it back in the above test may be worthless. But try it anyway. (Sometimes just removing and replacing the battery can clean the contacts enough)(for a while , anyway)