Won´t turn it on

I changed the memory ram, changed the hard drive and it turns on, i installed the mac os x leopard and after this, the PowerBook doesnt turns on again...

it doenst sounds the chime, doesnt answer for the power button

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Hi Glen,

The problem could be the power switch itself if no power when bridging the contact points just after the switch. But the top case ribbon cable could also be the culprit or the logic board top case socket. I don't remember if you can disassemble/replace only the switch or the cable or if you have to replace the whole top case to do the repair. Check ebay listings for these parts but I think you can buy the complete top case for cheap and swap your keyboard on the working top case. Hard to troubleshoot the problem without known working spare parts.

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I have a G4 1.67 with the same problem, won't turn on. Bridging the solder pads works!

Now to find the fix... I tested the power button with an ohm meter. The button works. The button plugs into a socket on the back of the top case. There are two solder pads on there also. Bridging those pads does not start the computer.

The problem must be on the cable or on the logic board, right? Any suggestions on what to test?

P.S. I considered posting a new item, but this is so closely related to this thread, I thought it would be applicable to others looking for this same problem.

Thanks!

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I was able to test the power button all the way to the inside of the ribbon cable connector. The power button goes to the first and fourth pins on one side of the connector. With the ohm meter on the ribbon cable connector, pushing the power button closes those pins. That tells me that the power button is good all the way through the connector.

This next part is a bit of a guess. At the solder pads on the logic board, I found continuity from one pad to one of the pins on the logic board socket (the first or fourth pin on one side). I could not get continuity from the other solder pad to a pin on the socket. This might mean there is some failure on the logic board.

I'm going to run the computer without shutting it down. As long as the system is always running or goes to sleep, I might be ok for quite a while. However, some day I'll need to hit the power button again. I might try to solder the power button directly to the solder pads on the logic board, obviously a risky solution. I've replaced capacitors on motherboards before, so maybe this is possible.

Maybe I'll look for a top case just in case some part of my testing was flawed.

Thanks for the tip about bridging the pads on the logic board! How awesome!

Glen

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Glen, if the problem is the logic board top case socket then solder the power button directly to the PWR solder pads would be an alternative solution and I'm pretty sure it would work. I had a discussion with Ben Eisenman on the same subject in another thread and Ben agreed that it could be a good repair solution but we never tried it. If you try it please post the result here. Thanks Glen and good luck :-)

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I soldered the power button directly to the logic board and it worked. You need a really small wire, and very short leads exposed. I used the wires from a headphone extension cable.

At first, the computer was acting like I was continuously holding the button down (ie: I got the long tone form the PMU reset) This was because I guessed wrong and had the leads reversed. If the leads are reversed, you get a continuous circuit. I just reversed the new wires on the power button since that was easy to solder.

If I ever have to remove the top case, I think I'll cut the wires and insert some kind of connector so I don't have to re-solder anything.

Thanks again for the tips!

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Thanks for the update Glen, glad that the repair worked :-)

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Reseat the RAM. Try starting from the installation disk. How much RAM do you have now? Will it start with the old RAM installed? What happened after the system install? Did the install complete?

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after system install (complete install) it boots properly, i logged into the mac os x, registered the software, so i turn it off. and next time it didn't turns on.

dont start with the old ram, neither with the new ram

tried top case connection, ac adapter seems ok the green led is on, battery almost new...

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Maybe the power switch (on the top case ) is going bad. To power up the PB with top case removed try to find two solder pads on the logic board there's an inscription near the two pads, search for PWR. I think the pads are located near the top case cable connector socket. Bridge the two pads with a small metallic flat screwdriver to power the machine. Check my answer to this question:

Computer won't turn on after replacing display.

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I'm no computer expert, but I had a similar problem with my old G3. My problem was that after I had taken the computer apart and put it back together, a main bundle of wires in rainbow color on the underside of the computer had come loose (it was somehow related to the power system)! I re-seated the conector in its socket firmly and that fixed everything! Hope that helps!

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I had the same problem with my PowerBook G4.

Do you have an airport extreme card installed? If so, take it out and try to start your computer up again, if it works, maybe your airport software is not updated.

See the following webpages for more info:

http://support.apple.com/kb/TA21384

http://manuals.info.apple.com/en_US/AirP...

http://www.thexlab.com/faqs/kernelpanics...

Hope this helps.

M

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