PRAM Capacitor to PRAM Battery in the iBook and 12" PowerBook G4 models

[retr01]

I noticed something with my 12" iBook G4 that I recently picked up. It would keep forgetting the time and date every time I remove the battery. PRAM reset didn't resolve the issue. I discovered that none of the iBooks and the 12" PowerBooks have PRAM batteries. Those have PRAM capacitors, instead. Oh boy.

PRAM and Battery Issues in iBooks and 12″ PowerBooks | Low End Mac

The PRAM capacitors are relatively inexpensive, but the procedure is difficult. This is what the PRAM capacitor looks like:

I could not find a guide by iFix for the step-by-step procedure for the PRAM capacitor. However, getting to the logic board iFix has the steps for various iBooks and 12" PowerBooks. For the 2004 12" iBook G4, this is the guide:

iBook G4 12" 800 MHz-1.2 GHz Logic Board Replacement

The motherboard includes all ports except the DC-In board.

www.ifixit.com

Then, the location of the PRAM capacitor depends on the iBook and 12" PowerBook model. For the 2004 12" iBook G4, the location is shown below:

 

[retr01]

Hey @rjkucia, is your 12" PowerBook G4 having this issue, too?

 

[retr01]

Hmm, I stumbled on an interesting "heated" discussion about the PRAM capacitor in the iBooks and 12" PowerBooks.

PowerBook 12" clock battery?

Steven Fisher wrote on 21 December 2008: Does the 12" PowerBook G4 (1GHz, i.e. early DVI) have a clock battery? I know it doesn't have a full backup battery, but it seems to be losing the system clock a lot lately and I don't remember that happening before.

www.dssw.co.uk

 

[rjkucia]

Mine does have the capacitor as well, I haven't really tested it but it seems to hold a charge for long enough? In any case, my battery works fine enough, and I can't imagine this would motivate me to open that damn thing up again anyways lol

 

[retr01]

Mine does have the capacitor as well, I haven't really tested it but it seems to hold a charge for long enough? In any case, my battery works fine enough, and I can't imagine this would motivate me to open that damn thing up again anyways lol

Yeah. Even if the removable battery pack dies and cannot be recharged sufficiently, the iBook and 12" PowerBook will lose time, date, and maybe a few other settings because the PRAM capacitor only can power the PRAM for a handful of seconds. So, best to have a well-conditioned battery pack in those laptops.

 

[3lectr1c]

The ones in the clamshells are starting to leak.

iBook G3 pram capacitor schematic

I disassembled my iBook G3/300, and the PRAM supercapacitor was fairly yucky I tried to put a replacement in but couldn't get the solder to stick well to one of the holes. In the process of trying to do that I brushed the side of the cap with the iron and ruined it, so I'll need to get...

68kmla.org

It certainly isn’t unheard of, the original Xbox uses a similar but larger cap and it’s infamous for leaking.

 

[retr01]

I have tried to find out if anyone has ever converted from a PRAM capacitor to a PRAM battery. A tiny board solders to the original hookups, and it already has the necessary resistors and other components with a holder for a coin-sized battery.

 

[retr01]

By the way, if anyone wants to replace the PRAM capacitor in an iBook or 12" PowerBook, the specifications are:

5.5V and 0.33F​

New battery won't charge - PRAM capacitor problem?

Bilingual Website: Informationen rund um die iBook Clamshell Serie, die Apple 1999 auf den Markt brachte. Hardware, Software und Wissenswertes zu den bunten iMa

ibook-clamshell.com