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Hi all,
I picked up a G4 iBook (1064GHz) on eBay to fix up. As the description said it starts up with a loud fan noise and black screen. I'm waiting for a power adapter for it so I just have the charge on the battery to play with for now. What are the first things I should do while there is some charge left? How does one 'reset' the backup battery?
Thanks,
-Erik
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I'd remove the extended RAM and Airport just to rule those out, and then immediately reset the PMU and PRAM. Another test is to see if target mode and option mode happen to work immediately upon powering up, and before the fan-on-high situation kicks in.
You're not likely going to be able to effectively test external video in the fan-on-high/black screen state...generally this state is sort of a defense mechanism that the computer goes into when something is wrong, and video will not appear until the problem is alleviated, so if you don't see anything on an external screen, I don't think that necessarily means anything at this point.
The most likely cause in this situation is logic board failure. Second most likely is that removing RAM/Airport/battery and doing resets may resolve the issue. 3rd most likely is that if you go inside the machine and do exploratory surgery, you'll find something goofy (loose screws, bent shielding causing a short, etc.) that is forcing the laptop into this state. I would be tempted to disconnect the hard drive and then the optical drive, and see if that causes the machine to behave differently.
Once (but unfortunately only once) a machine in this state went back to normal when I disconnected the fan and then powered on with it disconnected. When I re-connected the fan and powered on again, the machine was fine. But again, it only happened once, and this is not typically a fix that ends up working.
Also, it's a longshot, but if you pop the back of the screen casing off, check to see that the video cable is fully seated. Sometimes loose connections can cause a laptop to panic and go into this state.
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Rdklinc,
There's no ram (probably salvaged previously)and no airport card. How do I check the target mode and option mode? If target mode is using the iBook as an external HDD, I do still have a Pismo that works with 10.3 on it. I just don't know the steps. I'll try Googling it though.
Check target mode by holding down "T" while powering on, and option mode by holding down "option" while powering on. Also, while I think there's some valid info in my post, and that there are many issues that can cause the "fan on high/black screen" issue, I think Lemerise is very much on target, and if the resets, etc., that I suggest do not help, then the problem is very likely what he describes.
rdklinc, I finally opened up the bottom and the loud noise is coming from near the grill on the side
with the ports. The fan in the back middle is not turning at all. I tried unplugging/plugging it in but it still doesn't spin. I'm guessing the noise is
actually the HDD. Still, the fan should spin and I should get a grey screen with spinner even if the HDD is kaput, no? Would a bad fan stop the unit from at least booting to bios?
You're right, a laptop generally still functions to a certain level even when it has a bad hard drive, so I'd guess the problem is more than a bad hard drive (if the drive is in fact bad). Could you describe the noise it's making? I take it option and target mode didn't work at all? You might try disconnecting the hard drive, and then powering on, and seeing if the laptop behaves differently, and that will also tell you without a doubt if the sound is the hard drive or not. Beyond that, I'd refer to the procedure Lemerise suggests. I suppose it's possible you have a bad screen AND a whining hard drive, and not the condition that Lemerise's suggestion solves, but that seems unlikely. Connecting to an external video source will rule that out -- if you see something on an external display, you know the problem is the screen or the video cabling. But hey, you've got the laptop open, so check for the de-soldered pin as Lemerise suggests...that's the most likely culprit.
I tried heating the pins already when I had the bottom open. I'll order a vga adapter to try external view. I did power it while open and the fan does not spin. Should it run
right at startup? I'll try removing the HDD soon.
I had not gotten that far and reassembled the unit to try and run it.
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Clearly a U28 desoldered chip on the logic board. Just apply solder iron tip on pins 1 and 21 to resolder them.
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To quote you on 11/23/09 "That's micro soldering stuff so a skilled technician should do the soldering job."
Yes, there's always the risk to bridge the other pins if you don't know what you're doing. But it's an easy job if you use a fine tipped solder iron.
Wow, that's awesome, thanks! Do you happen to have a diagram, or a link to a picture? Thanks again!
I'd be interested also. The cheapest logic board I've seen for sale is $90 and I'm a little short on R&D funds this month.
If you Google <<ibook g4 u28>> you'll get more info about this ibook G4 failure but you can also check these links:
http://macintoshhowto.com/hardware/how-d...
http://s291.photobucket.com/albums/ll306...
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Mayer,
I have a 10.3 disk somewhere. I don't have an adapter for the apple style vga port but I was planning on getting one eventually anyway. I'll try booting with the disk and reporting back. I found instructions on how to clear the PMU (shift-control-option-pwr button) and the first time I tried it I got the tone but after that nothing and trying it again brought no more tones. Is there also a PRAM to disconect in the iBook?
staggerwing 의
Just tried the disk but it looks like there's already one in the drive. Guess I'll have to open it up to get that out first (no eject button on the slot-loading DVD drives, right?)
staggerwing 의