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G3 won't boot at power on until reset

Z

Zippy Zapp

Experienced Member
Joined
Dec 13, 2014
Messages
258
Location
USA:CA
I have a beige G3 tower (newer revision) that I recently repartitioned the HD to make sure the system software was located on the first 8GB and now it is doing something peculiar. When I turn it on with either the adb keyboard or the power button it does not boot at first. It makes the chime and it sounds like the HD is spinning up but it just sits there. Sometimes the power light will not be on either. The monitor does not get a signal.

If I hit CTRL + Command + ADB Power button to reset it, it chimes again, the monitor comes to life and it boots right away and works fine.

I have tried resetting PRAM, no change. I did use the reset button on the motherboard (Cuda?) and after this it boots fine but the next power cycle it is back to not booting without a reset.

It does not have the original drive and I have not tried a different drive but it was working fine with this drive before the repartition. The only other thing I have not tried is reseating the voltage regulator module. But since it does make the chime i and boots after reset I think this is likely fine.

Has anyone come across this problem? With all the years I have owned Macs I have never seen this issue.

Thanks!
 
Hi,

PRAM battery is fresh and proper voltage.

Startup Disk shows the correct boot volume is selected.

Thanks!
 
I found that my G3 will behave the same way if I have the jumpers at J16 set for too high a CPU speed. It's a random thing--you always get the chime, but real startup from power-off is a throw of the dice. Set the CPU speed back to factory and it's solid.
 
Hmm. I didn't tamper with the CPU speed jumpers, but you may be on to something. This G3 I got second hand and had lots of corrosion from a battery problem, which I fixed. The CPU module, though, is not stock. It has a hex turn switch on it and I think IIRC when I restored the original factory disk (8.1) it could not identify the CPU. I am not near the computer now but I seem to remember it was 700+ mhz or so. Did they make G4 upgrades for these ZIF modules?

I do know that this was originally a 266mhz G3 and that it does have the factory jumper bar (white) with sticker in place. I have wanted to return this to stock so perhaps I need to pickup a 266mhz module. I am guess the hex switch is probably for adjusting the speed of the module to match the speed of the bus or the jumpers? I don't really know anything about it.

Thanks.
 
There were a number of CPU upgrade modules available for it, so it sure could have been upgraded to a G4/700.
How much RAM do you have in yours? With 768MB in mine it takes almost literally FORVER to boot to a display, but it always does boot up, after SEVERAL minutes. For the record mine has been overclocked from 266 to 333 for over a decade it still always boots to a display, though I do on VERY rare occasion get a system lockup on bootup (usually while loading extensions right before the desktop shows up) and need to reset it (Running OS 9.1 on mine).
 
Hi RWallmow,

Thanks for the information. It is weird because it only started doing this after I partitioned and fixed the case. I thought I might have zapped something when I was re-assembling as I had removed the logic board in order to paint the case where the battery was because it had started to rust again after grinding it all away. I am not new to building and repairing computers so I was pretty careful. But who knows. I three finger salute always boots it up after I turn it on now.

As for the CPU, I guess I was wrong. Apple profiler reports (8.5, currently) 535mhz unknown CPU. I have 768MB installed. It also came with a PCI ATI Card, a Firewire/USB card and a Asante 10/100 net card. I removed all of those when I rebuilt it.

Thanks!
 
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