I have a Powerbook G4 400mhz that will not turn on. I plug the power in the power cord goes amber, then I press the power button and nothing happens. I replaced the inverter board no change. Would it be the PMU or the logic board? Is there a way I can tell before I buy one?
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Dead powerbook 400mhz
- Thread starter trainguy77
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My trusted old 400mhz Tibook died when I updated from 10.3.8. to 10.3.9 -- it was the motherboard battery -- the thing under the optical drive.trainguy77 said:
hmm so thats a battery strange...I was wondering where the battery was. I will have a look at that and see if it still has a charge.California said:
trainguy77 said:
this is way out of left field, but:
Perhaps you've got a bad capacitor in your power supply? Have you tried using your power supply to start up another Powerbook, or have you tried using a different power supply to start up your own Powerbook?
EDIT: though I do think California's solution is more likely
I have not tried the power adapter idea. I will give that a shot if i ever see someone with the same adapter. Well I have the battery in front of me, how many volts is it suppose to provide? I can not find that number. ONe side(red) is giving me 1.5 Volts, and the black side and the other side gives me nothing(from what I can tell) I am getting those readings from going the black connector to the white and red connector to white. However when I go black to red I get about .2 volts. So it looks like one side of the battery is dead. I don't know how much power it is supposed to give so that would help. Thanks.
YES! I think I have got somewhere, but not done just yet. I looked at the battery again and figured out its wiring method. So its dead for sure. Now finding a replacement, I think i may just make my own, however I think this is the problem. As when I try to turn the computer on now the power cord turns green, which makes me happy. However a joint that I soldered broke on the power adapter so I need to re-solder that and see if it turns on, see this computer has its fair share of mods............. But this is good I have been trying for weeks and this is the first sign of hope. So thanks I will get back to you guys soon, but would making my own battery replacement work if its the same voltage and wired the same?
However a joint that I soldered broke on the power adapter so I need to re-solder that and see if it turns on, see this computer has its fair share of mods............. But this is good I have been trying for weeks and this is the first sign of hope. So thanks I will get back to you guys soon, but would making my own battery replacement work if its the same voltage and wired the same?well I fixed the power button problem but it still does not turn on so maybe it needs the PRAM battery to turn on. So I think I will try make my own because new ones are not cheap.
trainguy77 said:
yea...it actually prolly is the PRAM battery. I just brought up the power supply issue because I had it with a desktop once. Enough electricity leaked through to run the lighted switch on the front (barely) but that was all it would do. Drove me freakin' crazy.
That I am still thinking about. For you that don't know what it looks like here is a pic i found(not mine) http://www.ifixit.com/Guide/21/images_large/29.jpg its in the top right with the numbers: 616-0114A. So it has 4 3v cells. I think I should be able to go make my own and wire it in using the current wires. I took the black cover off and they are wired very interestingly. But I should be able to make my own, however I don't know if they are rechargeable. Any help would be great. I am going to phone around and see what I can do. I have never done this before though.........disconap said:
So I phoned around and this one company will do it for about $20 cdn. They have the same type of cell and they will do the labour of connecting it. They told my soldering on batteries decreases there life I have heard that before so I am not going to take the chance, i will let them do it.
They told my soldering on batteries decreases there life I have heard that before so I am not going to take the chance, i will let them do it. 
So what happened?
So what happened after you replaced the PRAM battery? Did your Powerbook come back to life? I'm in the same situation right now. My Powerbook was rejected for a trade-in because it wouldn't turn on, but I'm very suspicious that it might just be the PRAM battery because it was acting very difficult for several weeks whenever it was powered off or restarted, but not when it was put to sleep mode. During normal use, it worked fine and it passed the full battery of TechTool Deluxe tests right before the last time I powered it down.
So what happened after you replaced the PRAM battery? Did your Powerbook come back to life? I'm in the same situation right now. My Powerbook was rejected for a trade-in because it wouldn't turn on, but I'm very suspicious that it might just be the PRAM battery because it was acting very difficult for several weeks whenever it was powered off or restarted, but not when it was put to sleep mode. During normal use, it worked fine and it passed the full battery of TechTool Deluxe tests right before the last time I powered it down.
I still don't have it working. Its dead.....With the new battery no go. However, the lights changed on it again(the power cord) So I think that helped but I think the PMU is dead. So I have not had time to find one for cheap. I have already replaced the inverter board....but that did not help...I just hope its not a logic board.....I don't know if its worth the money for a PMU....
I have already replaced the inverter board....but that did not help...I just hope its not a logic board.....I don't know if its worth the money for a PMU....
I got my PB back today and I actually managed to coax it into starting up. I don't know if this'll help you or anyone else, but the way I get my comatose PB to start up is like this:
- I leave it powered off for a while (12 hours to several days). Sometimes I'll try running only on AC. When I got my PB back, the battery was completely discharged. Don't know if that helped me get the machine restarted or not.
- I plug it back in
- Start up by pressing and holding the power button for over 30 seconds or until it shuts down. When it fails to start, it powers on, but the screen remains black.
Sometimes it won't start right away, but it'll make it through hardware tests and beep. I got one beep this time (No RAM installed), but I've had multiple beeps before in the past (can't remember how many). If it gets to the point where I get the hardware test error beeps, it'll usually start up if I keep the power button held down or it starts up the next time I try to power it on.
- If it doesn't start, I wait a minute after it powers down and press and hold the power button again.
Don't ask how I came upon this odd ritual. I tried everything else imaginable before and this appeared to be the only thing that got the PB revived. Resetting the PMU didn't work. Running on AC didn't work. Changing the RAM didn't work.
Now that I got the machine past the boot-up phase again, it's working fine. It wakes from sleep and does everything else normally. I just can't shut it down unless I want to go through the whole circus I listed above.
I think I'm going to try replacing the PRAM battery and see if that works. I've been finding some online for $20/us.
Well, I'm happy to report that my G4 Ti Powerbook is back from the dead after a PRAM battery replacement. It didn't come right back without some coaxing though.
After I replaced the PRAM battery, nothing changed. When I hit the power button, the machine would power up, but it'd never get to the point of doing hardware tests and there was no startup chime. I repeatedly turned it on and off by pressing and holding down on the power button and reset the PRAM multiple times until it finally gave me the start up chime and turned on like nothing was wrong. If several tries failed to get the machine to start up, I tried taking the battery out and unplugging it for a day or two before going back to it. I have no idea if that does anything, but before it totally died, there was a period of time when I could get the machine to eventually start up again if I left it alone for a day or two.
Anyway, after it powered up, I put the machine in sleep and it woke just fine. I kept it on for a while and powered it down after a while. It powered up just fine. I tried a restart and had no problem.
After I replaced the PRAM battery, nothing changed. When I hit the power button, the machine would power up, but it'd never get to the point of doing hardware tests and there was no startup chime. I repeatedly turned it on and off by pressing and holding down on the power button and reset the PRAM multiple times until it finally gave me the start up chime and turned on like nothing was wrong. If several tries failed to get the machine to start up, I tried taking the battery out and unplugging it for a day or two before going back to it. I have no idea if that does anything, but before it totally died, there was a period of time when I could get the machine to eventually start up again if I left it alone for a day or two.
Anyway, after it powered up, I put the machine in sleep and it woke just fine. I kept it on for a while and powered it down after a while. It powered up just fine. I tried a restart and had no problem.