Powerbook g4 wont turn on.

Welcome to discussions, SSMMAC. This is definitely a good place to come and there is help to be found here.

The backup battery is a coin-type Li-Ion cell mounted into a circuit board and tucked under the optical drive and modem/inverter board. It's not overly difficult to replace, if you have T-8 and T6 screwdrivers handy. I think you'll find what info you need here:

http://www.ifixit.com/Guide/Repair/Installing-PowerBook-G4-Titanium-DVI-PRAM-Bat tery/102/1

That being said, you may need to charge it overnight with the main battery out of the computer. What is the condition of the main battery? Do you get four green LEDs when you hit its test button? At the probable age of the computer, though, it is quite likely that the backup battery has gone past end-of-life into not working at all.

Are you getting the normal "glow light" from the power adapter plug when it is plugged into the laptop? The TiBook power adapters that shipped with the computers proved to be problematic over time, as there was not sufficient strain relief on the cord coming out of the computer connector.

SSMMAC wrote:
Ok, the charger is not making a light but it is a off brand (not apple) charger, will it still work? I think the main battery is out of power completely, but, if the backup battery (internal) is drained will the powerbook still run with just the main (external) bat.?

If the power adapter is actually compatible, though you probably wouldn't have the charged/charging (green/amber) LED indication feedback. The Titanium adapters provide 24.5 volts DC and 2.65 amps of current.

With respect to the main battery, you should have the green four-LED array and test button and when pressing the button, four LEDS will light for a fully charged battery, fewer for partially charged batteries. If you are unable to charge the battery in the computer, then either the battery has completely failed (which will happen after several years, though I do have an eight-year-old Apple battery that still holds up pretty well), the DC-In board in the computer has failed, or the power adapter is not working.

The backup battery is there mainly to hold up the system time of day clock and parameter RAM contents, though it is supposed to be able to support a couple of minutes of "sleep" to enable battery changes with the computer on. If the backup battery is weak or gone, then what can happen is that data read from PRAM at boot can be bizarre and cause strange boot-time behavior, up to and including not being able to power the machine up.

That being said, you need to verify that you can charge the main battery, because even with a working backup, if the machine has no DC power available (which could be the case if the power adapter or DC-in board are not doing their things) then nothing is going to happen. Charging the main battery will more or less eliminate those two failure suspects and you can work from there.

Just as an aside, what is the acutal power adapter you are using? I guess I haven't acquainted myself with aftermarket power adapters for the TiBooks.

Message was edited by: old comm guy

SSMMAC wrote:
Thanks so much. But no luck. I researched and I am going to unplug the internal PRAM, they say it should boot up then, your input? The charger I have no idea as I bought it from a computer store. Thanks.

Assuming you meant the PRAM battery, the logic board connector to the battery is under the keyboard basically at the lower right of the opening, a three-wire connector with red, white and black wires going to it. Much easier than disassembling things to get the connector off the battery PWB itself.

First off, try a safe boot by holding down the shift key when booting. You should be able to get to the login screen. Now...how do deal with the password issue? You can outfox the system by making it think the next boot is the first one after a new system install. You have to go into single-user mode, but it is really straightforward if you follow the instructions here.

http://gigaom.com/apple/reset-os-x-password-without-an-os-x-cd/

If you can't get that far, though, we have a couple of other things to try before things get too drastic.

SSMMAC wrote:
One More thing......I remembered when i first turned on the mac it said something like "date set back to Jan 1972 may cause problems" would that be my problem with startup?

That wouldn't be a problem, just an indication that the backup battery ran down completely so the clock would default to 1/1/70 midnight GMT. Normally we don't see that because during the boot process, provided you have an internet connection, the system will query the Apple timeserver and get the current time.

That might help, but here is another thing to try: open firmware

Boot up holding the cmd-option-O-F key combination until you get a white screen with open firmware information. You are not involving the disc or probably even parameter RAM much at this point. Enter the following three commands and see what happens:

*reset-nvram <cr>*
*set-defaults <cr>*
*reset-all <cr>*

The third command will cause a normal reboot, which may or may not proceed well; we'll have to see.

NVRAM reset is kind of like a PRAM reset but actually goes much deeper into the machine and often cures a number of sticky problems.