PowerBook G4 does not start. PRAM Battery?

[zoiko192]

Good afternoon, I recive the community of MacRumors to help me relive my old powerbook, I want to know if anyone has an idea of the reason for not starting, I have a powerbook G4 1.25Ghz 15 "(FW800 - Al)
I've been this week trying to revive it and sometimes I'm lucky and it turns on the system starts, although it lasts a few minutes and freezes.
When turning on it does not give the start beep, then the screen is simply off, it is not the screen because there is no sound or light on the keys.
A few days ago I changed the thermal paste and checked the motherboard thoroughly without finding any kind of shortcuts. Also clean the entire plate with clean contact liquid, but I still do not get results.
Try to do a pram but it does not work.
Do you think it has something to do with the internal pram battery?
Could it be the old battery?
Maybe ram memories?
Does anyone have an idea of the problem?
Sorry for my English

 

[z970]

Did you try reseating the RAM?

If that doesn't work, use one of those precious opportunities you're booted into the desktop to quickly find out if the RAM is OK. You can do this by selecting the Apple icon in the top left of the menu bar, selecting "About This Mac", then clicking the "More Info..." button, then going to the "Memory" section under "Hardware" in System Profiler, which should have launched when you chose "More Info...".

When you get there, you should see an interface similar to this one.

If both RAM cards check out under "Status" as "OK", we can rule out any memory issues and move on to possible hard drive failures. Keep us posted.

 

[covisio]

Could be that the PRAM battery is dead/completely discharged. This will cause it not to start up. This happened to mine after it had been sat in a cupboard for about 2 years. I replaced the battery and it fixed the issue.
There is a workaround I believe where if you disconnect the PRAM board from the main board, then power from the mains, it will fire up. Not tried it myself but this is what I've read.

 

[pl1984]

You may wish to try resetting the Power Management Unit (PMU). You can do this by holding down the "Shift", "Control", and "Option" keys along with the "Power" button, all simultaneously for approximately five seconds. Then attempt to power on the system using the power button.

I had a 17" PowerBook 1.5GHz which would initially power up after being powered off for a number of days. If I attempted to reboot or power on after shortly shutting it down it would refuse to do anything until I reset the PMU. I initially suspected a bad PRAM battery but, after replacing them I concluded the PRAM battery was not the issue. Something was wrong with it and only a PMU reset (or leaving it unpowered for days) would enable it to start.

 

[zoiko192]

Did you try reseating the RAM?

If that doesn't work, use one of those precious opportunities you're booted into the desktop to quickly find out if the RAM is OK. You can do this by selecting the Apple icon in the top left of the menu bar, selecting "About This Mac", then clicking the "More Info..." button, then going to the "Memory" section under "Hardware" in System Profiler, which should have launched when you chose "More Info...".

When you get there, you should see an interface similar to this one.

View attachment 765119

If both RAM cards check out under "Status" as "OK", we can rule out any memory issues and move on to possible hard drive failures. Keep us posted.

Check the ram memories on my other power pc and they seem fine. I tried other memories that I have and sometimes the white led blinks but does not ring. It could be a memory socket problem or a memory problem. the disc is discarded because I checked it. Thanks for your reply.
[doublepost=1528393647][/doublepost]

You may wish to try resetting the Power Management Unit (PMU). You can do this by holding down the "Shift", "Control", and "Option" keys along with the "Power" button, all simultaneously for approximately five seconds. Then attempt to power on the system using the power button.

I had a 17" PowerBook 1.5GHz which would initially power up after being powered off for a number of days. If I attempted to reboot or power on after shortly shutting it down it would refuse to do anything until I reset the PMU. I initially suspected a bad PRAM battery but, after replacing them I concluded the PRAM battery was not the issue. Something was wrong with it and only a PMU reset (or leaving it unpowered for days) would enable it to start.

It does not work, when I keep pressing the keys "Shift", "Control" and "Option" together with the "On" button the system remains on as explained in the first post, then I have to force the shutdown of the system. It does not get to whistle.
I suspect the pram battery
[doublepost=1528393822][/doublepost]

Could be that the PRAM battery is dead/completely discharged. This will cause it not to start up. This happened to mine after it had been sat in a cupboard for about 2 years. I replaced the battery and it fixed the issue.
There is a workaround I believe where if you disconnect the PRAM board from the main board, then power from the mains, it will fire up. Not tried it myself but this is what I've read.

Thanks for the answer, I will try to change the battery, I do not think I find similar in my country.
I will keep you informed

 

[zoiko192]

I tried to turn on the powerbook without the pram battery module, it did not work.
I measured the voltage of the battery, mark 2.52v being the 3.7v battery, do you think it affects something?
I leave images.

 

[zoiko192]

New advances
I soldered an adjustable source simulating a battery to the pram battery module and set it to 3.7v. It seems not to work although now the probability of a tone has risen, also 4 times out of 10 it does not detect the ram module and it turns on the white led and most of the times there is no single LED tone.
The system almost started once but when it reached the load it froze.
The system's general startup beep is more likely but it does not go over there.
I think the damage is on the motherboard.

 

[pl1984]

It does not work, when I keep pressing the keys "Shift", "Control" and "Option" together with the "On" button the system remains on as explained in the first post, then I have to force the shutdown of the system. It does not get to whistle.
I suspect the pram battery

I'm not surprised as the symptoms you described didn't match the ones I experienced. Thought I'd throw it out there as it's a simple thing to try.

As for the PRAM battery I do not expect that will solve your problem either.

 

[z970]

Try replacing the hard drive.

 

[AphoticD]

I would try isolating the fault by disconnecting/removing further components.

I’ve seen this behavior recently on a 1Ghz FW800 AlBook due to a failed AirPort Extreme card.

 

[zoiko192]

I would try isolating the fault by disconnecting/removing further components.

I’ve seen this behavior recently on a 1Ghz FW800 AlBook due to a failed AirPort Extreme card.

I unplug some components but it does not work
[doublepost=1528472732][/doublepost]

Try replacing the hard drive.

It does not work

 

[AphoticD]

I unplug some components but it does not work
[doublepost=1528472732][/doublepost]
It does not work

I think it would be time to hunt around for a replacement logic board.

 

[z970]

Try looking for a higher spec board, providing it physically matches up to the case.