I recently got a G3 blue and white. I noticed that at some point someone had replaced the heatsink clamp with a non standard wrong sized one. When i was cleaning the computer i found the original one under the hard disk tray so i decided to put it back on. Well i guess i got it backwards and the heatsink was slightly tilted. I didnt notice until i had already tried to start the computer twice for a total of about 30 second of on time. Now i can turn it on and i can turn it off and nothing else. It does not bong and if i remove the memory it does not beep. Do the blue and white G3s have any kind of overheat protection, what are the odds that i killed the cpu. Does anyone know where i can get a replacement for a reasonable price, its a 350mhz, i do not see any on ebay at the moment.
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Powermac G3 B&W possible dead cpu
- Thread starter mustagcoupe
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Did you try the CUDA reset button.
ZIF cpus can be a bit fickle and PowerPC Mac's in general. I have had the same result upgrading the CPU in a Beige G3 and a PowerMac 9600. Both with the original CPU worked just fine, but when I put in the upgrade they powered on, but nothing else, just like you have. Only putting back in the original CPU made them work again, then I powered them down and held the CUDA reset button for 10 seconds or so, removed the original cpu and replaced it with the upgrade.
This worked both times, the Macs boot chimed and work just fine, the CUDA is sensitive to CPU changes.
I highly doubt you burned a G3 with 30 seconds of power on without proper cooling, either it was already dead, or you need a proper CUDA reset.
Sadly there seems to be a shortage of ZIF CPUs on the market and you may need a good one to do a proper CUDA reset.
ZIF cpus can be a bit fickle and PowerPC Mac's in general. I have had the same result upgrading the CPU in a Beige G3 and a PowerMac 9600. Both with the original CPU worked just fine, but when I put in the upgrade they powered on, but nothing else, just like you have. Only putting back in the original CPU made them work again, then I powered them down and held the CUDA reset button for 10 seconds or so, removed the original cpu and replaced it with the upgrade.
This worked both times, the Macs boot chimed and work just fine, the CUDA is sensitive to CPU changes.
I highly doubt you burned a G3 with 30 seconds of power on without proper cooling, either it was already dead, or you need a proper CUDA reset.
Sadly there seems to be a shortage of ZIF CPUs on the market and you may need a good one to do a proper CUDA reset.
I think i did the cuda reset procedure correctly, when it had no effect i removed the pram battery and let it sit overnight unplugged, no change in its behavior. It is the stock processor, the computer worked before i removed the heatsink and processor and i have not touched the jumper block. I just pulled the processor again to take a close look at it and i see no burn marks on the cpu die or any funny looking components and it had no smell at all. Do these have problems with the contacts. I have never seen a cpu with such large and widely spaced pins before. I suppose when i put it back together i can work the cpu lock back and forth to try and rub any corrosion off the contacts and see if that does anything. Currently the only thing in the board is the power plug, processor and memory. i unplugged everything else from the computer to see if there was any change and there was not.
There can be issues with pressing the CUDA reset more than once, I've done this before, and it resulted in the same issue you are having. Replace the pram battery and press it only once for 30 seconds with a known good cpu and proper jumper settings.
If that fails, hold the power button and see if it enters programmer mode, you'll hear a tone..keep holding the power button, you'll hear a chime, let go. The system will enter Open Firmware with the defaults loaded.( You'll need the video card ).
I've also had issues with ZIF cpus and too much thermal paste extending from the die onto the other resisters, cleanup any excess. The paste should only be on the die.
If that fails, hold the power button and see if it enters programmer mode, you'll hear a tone..keep holding the power button, you'll hear a chime, let go. The system will enter Open Firmware with the defaults loaded.( You'll need the video card ).
Code:
reset-nvram
set-defaults
reset-allI've also had issues with ZIF cpus and too much thermal paste extending from the die onto the other resisters, cleanup any excess. The paste should only be on the die.
I worked the latch back and forth with the processor in the socket a bunch of times, removed it and blew into the socket then put it back in and did it a couple more times. Then i held down both buttons on the motherboard for 10 seconds each. Then i tried powering it on, nothing, i pressed and held the reset button for about 3 seconds and then released it and the computer immediately bonged and attempted to boot. I plugged the hard drive back in and i had to do a pram reset to get it to boot but it finally booted all the way up. Not sure which thing finally got it to boot but its working for now. This machine is a very early rev A made the last week of december 1998 and my experiences with it seem to be matching up with everybody elses experiences with rev A's, its very temperamental. I have to remove the original 12gb hard drive to wipe it and test it to make sure its still good and im dreading that its going to throw an absolute fit about it and its going to take me forever to reinstall an operating system.
It does not always want to power on right away. Sometimes i have to hit the reset button on the front of the case at least once before it will bong. Does anybody know why it does this, is this just one of those rev A problems or is there something wrong with it. Once i get it to bong it always works flawlessly. I was able to reinstall os 8.6 with no problems.
Could be the PSU and the possibility of needing to “pre-heat” its’ circuitry. (Failing trickle voltage?) Have a friend that swears by using a hair dryer to pre-heat some failing PSUs - but that’s never worked for me, yet.
Did have one B&W here recently that had similar symptoms as yours. Wouldn’t completely boot on the first or second attempt… but usually on the third attempt it would then fully boot. I just swapped out the PSU and no more faltering boots. Figured I’d maybe recap that failing PSU later.
I know it sounds odd, but you might try the “hair dryer trick” before a cold boot just to see if it would then boot on first attempt. Of course, experimenting with varying times of pre-heating, before each dead-cold cold boot attempt. If it works better with the hair dryer ritual... I’d suspect the PSU.
21 to 22 years on an original PSU from 1999? Not so bad really.
Did have one B&W here recently that had similar symptoms as yours. Wouldn’t completely boot on the first or second attempt… but usually on the third attempt it would then fully boot. I just swapped out the PSU and no more faltering boots. Figured I’d maybe recap that failing PSU later.
I know it sounds odd, but you might try the “hair dryer trick” before a cold boot just to see if it would then boot on first attempt. Of course, experimenting with varying times of pre-heating, before each dead-cold cold boot attempt. If it works better with the hair dryer ritual... I’d suspect the PSU.
21 to 22 years on an original PSU from 1999? Not so bad really.
Probably a Rev A issue. Also you might have damaged something once you ran the system without the proper mounting schemes. Never had a blue and white, but I know people despise Rev A boards.
as a rev a owner, I can personally vouch for them being the pickiest computers to exsist
Whatever it is its something with either the cpu or the socket. Theres an led next to the processor that when the computer wouldnt boot up would light up bright then go off. When it would boot the led would light up bright, then go off, then flicker dimly several times and the computer would bong. I took the heatsink off and rocked the lever back and forth a bunch of times and for now its booting reliably. I have the memory up to 768mb and i added a flashed sil3112 sata card. I used my quicksilver to install tiger to a crappy old sata laptop drive in a firewire enclosure then removed the drive and put the drive in the G3 connected to the sil3112. Right now it has the original 12gb quantum fireball with os 8.6 on the ultra ata bus. The factory cd drive and the factory zip drive on their ata bus. And some 80gb seagate sata laptop drive on the sil3112 with tiger 10.4. The only annoying thing is i cannot boot into tiger from 8.6 directly because 8.6 cant see this flashed sata card. I have to boot into open firmware and do multi-boot to get to that primitive boot picker and then i can get into tiger where i can set it to boot normaly in the startup disk control panel. I have had absolutely no stabilty problems with this setup so far in several hours of use, it completed a run of cinebench r10 with no problems. It seems absolutely rock stable so far, i have not had a single crash or any sign of instability at this point, even the Cd drive has given me no issues so far.
I plan to replace the factory 12gb hard drive with something bigger and less noisy, either some random ide drive or a sata drive on an ide to sata adapter, whatever the computer will accept. I will see how that effects the stability of the computer.
I plan to replace the factory 12gb hard drive with something bigger and less noisy, either some random ide drive or a sata drive on an ide to sata adapter, whatever the computer will accept. I will see how that effects the stability of the computer.