View Full Version : G4 wont start without logic board reset

Oct 11, 2004, 04:32 PM
I have a sawtooth G4. lately i have been having difficulties restarting the machine. the green light would go on but no screen response or hard drive spin. only if i open the computer and reset the logic board it works. another restart and same story, light on, no screen no HD. i've had this computer for a few years and this has only began occurring in the last couple of months on irregular basis and now it's every time.

Oct 11, 2004, 04:35 PM
Could a dead battery be causing this?

Sun Baked
Oct 11, 2004, 04:54 PM
Could a dead battery be causing this?Probably, the dead batteries can cause all sorts of funky problems, the battery can be found at a Radio Shack if he doesn't want to drive to around to an Apple Store.

Little purple litium can battery (1/2 AA size).

Oct 11, 2004, 04:54 PM
so a dead battery would cause that? how can i get a new one? if that is the reason, power to U!

Oct 11, 2004, 05:03 PM
Hey read my post... G3 not booting up (http://forums.macrumors.com/showthread.php?t=92172) , I think you may have the same problem I am having... I replaced the pram battery and nothing.

Oct 11, 2004, 05:06 PM
BTW... Apple Store wont sell the batteries, I called and the discussion goes
Me: Hey I was wondering if you guys could sell me a pram battery for a G3 Blue/White Powermac
Apple Guy: No sorry we dont sell parts, but if you bring your mac we can special order you the part

So I went to radioshack, $15 for a damn battery that didnt even solve my problem :mad:

Oct 11, 2004, 05:10 PM
i saw your post earlier. thanks. i decided to post my case as well because mine works fine if i press the reset button on the logic board. only when i shut down or restart i have to do it again. did u try to reset the logic board?

Oct 11, 2004, 05:31 PM
I tried the Cuda button, including just hitting it with power off, then holding it down for 15 minutes, removing battery for a sec then hitting button and replacing it, none of these work sadly. What process are you using to reset the logic board?

Oct 11, 2004, 06:10 PM
i just shut down the computer, disconnect from the electricity, press the button for about 10 seconds, and presto... the machine works flawlessly, until i shut it down. everytime i reset the board i get the "date before 19..." error.

Oct 12, 2004, 10:46 AM
If you are running it on a higher resolution in OSX try turning it down to 800*600, reboot, (you may have to hit CUDA again) and once back in osx reboot again... see if this helps, I believe my resolution was a problem on the g3.

Sun Baked
Oct 12, 2004, 02:21 PM
i just shut down the computer, disconnect from the electricity, press the button for about 10 seconds, and presto... the machine works flawlessly, until i shut it down. everytime i reset the board i get the "date before 19..." error.People usually put in a new battery when the machine cannot remember the time, resolution, etc.

The stuff that is in PRAM, and needs the battery to stay there.

With the B&W G3 and/or Yikes G4, if the battery is dead -- there is a good chance that pressing the power button will do nothing (that's been my experience with this motherboard design.)

Oct 12, 2004, 03:30 PM
My problem is solved, I had the machine running fine when booted at a high resolution, but when it wrote to pram the machine could not boot at that high of a resolution, so i had to flush pram everytime i booted, until i downgraded resolution.

Oct 12, 2004, 09:15 PM
so how did you solve it? i just got a battery and it's no help.
u downgraded the resolution, and left it low? will i be able to use high resolution?

Oct 13, 2004, 01:53 PM
After I downgraded from 1280*1024 to 800*600 and found that it solved my problem I went up to 1024*768... I could try going higher but I dont like 1152 by whatever...

Oct 14, 2004, 10:23 PM
after 2 days of the computer working, it's dead again. i have to reset the logic board to get it to run!
any advice? i tried the resolution decrease and it worked, but when i went back to my old high res (23" apple cinema) its dead again. what happened to my machine?

Oct 16, 2004, 10:16 AM
Looks like you wont be able to run it in the high resolution, look for a lower resolution that it will work at :(

Oct 18, 2004, 05:30 PM
but how can that be? it worked until 3 or 2 weeks ago! what happened? any ideas, what could cause that? what changed?
what makes no sense is that it does work when i restart and put the high resolution back on, it just wont restart with it.
thanks for any input

Oct 18, 2004, 05:34 PM
did you try zapping the pram or resetting the PMU?

Lee Tom

Oct 18, 2004, 06:23 PM
i zapped the ram, and if zapping the pmu mean pressing the button the logic board i did. doing that is the only way i can start my machine up now.
any advice?

Oct 20, 2004, 10:42 PM
I dont know what caused the resolution problem, have you lately updated drivers or any software? It could be causing it... Otherwise might be a vid card failing... not sure though.

Oct 21, 2004, 12:30 PM
a video card problem..? interesting. when i restart the machine it works fine, it only happens when i shut down. only then i need to reset the logic board.
its very frustrating. still no solution. thanks for all the help though.