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imac g4 won't boot

reddrag0n

reddrag0n

macrumors 6502a
Original poster
Oct 1, 2007
624
163
Canada
i recently picked up an imac g4 800 mhz model, the 2002 version 15" and i am having the issue of it not booting.
i have tried different options but all have no effect.

tried new hard drive, same result
tried old drive, same result
tried new ram, same result
tried old ram, same result
took out some ram, same result

the result is, i can wait for 10 min and it will boot just fine. if i try to use it, it will work good for anywhere around 30 seconds to 5 min and then freeze (no beachball, no kernel panic, just frozen in time and stay that way until i turn it off). i will power it off, then power it on again and it starts, but no chime, no video. the fan spins up, the dvd seeks and there is a white led on the lcd, but that's it. power it off and on again to do pram reset and can't. it's hung. can't do open firmware, it's hung. i can press the cuda switch and sometimes it will allow it to boot but not every time. then it's right back to square 1.

was able to boot from the 1.2.2 aht and run a test, but it froze about 30 seconds into the test and just sits there.

i'm not sure what to do, wether or not i should punt this machine back to the original owner or tear this machine apart to it's original electronic components. at this rate, i'm really not liking these 800 mhz imacs as in my lifetime, this is the second failed one i have now owned. the first one got turned into a literal lamp
 
Does your iMac G4 give any signs of life? Startup chime? Flickering lights? Silence often points to a power supply issue.
 
flufftechnical said:
Does your iMac G4 give any signs of life? Startup chime? Flickering lights? Silence often points to a power supply issue.
Click to expand...
when i first start it, yes, chime and boots normally. after 30 sec to a few min, total freeze. then what i wrote above
MBAir2010 said:
check the lithium battery, that happens to my iMac g4 several times!
Click to expand...
was the first thing i changed out. i have one of those CR2032 fancy battery holders. it has a pic of a happy mac on it, and the 2032 is a brand new battery. i have the same in my quicksilver, mdd and other imac 17"
 
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i still have some of the parts to my original imac, so will be testing out the psu as per flufftechnical's post

*edit*
well, swapped in the very first psu, buttoned everything up, pressed the power button and it chimed and booted! i was able to play around in the os for a good 10 min and no hiccups. yay!!!

then i decided to shut it down and try to boot from the aht.....

booted the mac.... and now back to square 1 with no boot chime, no screen and a solid white led.
 
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well, i finally got it to boot off the aht, tried to run a test, it got past the airport test and then froze. turned it off now it won't start again.....
*bangs head against desk*
 
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reddrag0n said:
well, i finally got it to boot off the aht, tried to run a test, it got past the airport test and then froze. turned it off now it won't start again.....
*bangs head against desk*
Click to expand...
just keep trying, I wish had my Imac here to give better advice, but that is in Costa Rica now.
 
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all i want it for is another os9 machine thats a little more portable than my mdd, and a little more power and ergonomic than my pismo and titanium
 
IMG_8181.jpegIMG_8180.jpegIMG_8179.jpeg
 
Nothing sticks out as suspicious on those logic board pictures.

You mentioned that you tried a power supply from your previous failed iMac. Is it possible that both power supplies are bad… what was the cause of death of your original iMac?
 
years ago, i would say close to 10 years, was the gpu on the original. it just died. i put the default psu back in this one and pressed the cuda button then power and nada.

well i just pressed the power button again and now i have this...
image.jpg
 
ok, good news, i have now been able to do a proper pram reset, let it go for 3 chimes instead of it giving me 1 chime and continuing to boot on it's own, and was able to get into open firmware and reset that. it booted into osx and now as i am typing this is froze at the date and time screen


and back to square 1

 
from what i am reading online from other imac owners of the 17" and 20" versions, they are explaining the exact same symptoms with their units too. they are saying it's a failed psu but when i look at the default and the original that i have, no caps are bulged, no leakiness of fluid, so i am thinking it's a bad controller chip on the psu boards


https://www.reddit.com/r/VintageApple/comments/5sb5nx


these are pics of the original from 10 years ago

IMG_8186.jpegIMG_8187.jpegIMG_8188.jpegIMG_8189.jpeg
 
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I’ve seen some references to reviving this model iMac with a hairdryer. The symptoms you are seeing could match either of two scenarios:
A. The power supply is failing and does not provide stable power after it warms up. This is less likely since you’ve tried 2 power supplies.
B. There is a bad solder joint somewhere and the heating up causes the joint to become unstable. It could also explain why you have different symptoms after you’ve run the system and restart.

I suffered with scenario B on a 17” MacBook Pro. I could get another year of stability out of it by gently baking the logic board in my oven, which I did a couple times.
 
Brandon42 said:
I’ve seen some references to reviving this model iMac with a hairdryer. The symptoms you are seeing could match either of two scenarios:
A. The power supply is failing and does not provide stable power after it warms up. This is less likely since you’ve tried 2 power supplies.
B. There is a bad solder joint somewhere and the heating up causes the joint to become unstable. It could also explain why you have different symptoms after you’ve run the system and restart.

I suffered with scenario B on a 17” MacBook Pro. I could get another year of stability out of it by gently baking the logic board in my oven, which I did a couple times.
Click to expand...
i could reflow the solder using leaded solder. if thats the case then the leaded solder would work better than that ROHS crap they have been using
 
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