Power Macintosh G3 B&W not booting

[yntzl]

Hello everyone,

I have the same problem as this guy http://68kmla.org/forums/viewtopic.php?f=13&t=20786 but the problem like this guy isn't the RAM. I've cleaned the motherboard, memory and the graphics card (the original Rage 128) with isopropyl alcohol, I swapped the RAM sticks and installed some new ones, checked the PSU voltages and started up the Mac without the hard drives but the problem persists. I did overclock this Mac, It is a 350MHz model and was running in 400MHz with no problems at all. I've turned off the machine normally, in the next day the problem started, but the Mac stayed on this state for about 30 minutes, and when I've pressed the restart button the machine booted, but now even doing this the computer does not start up, and I also reverted the overclock.

What this can be? Bad CPU? I dont think that is a bad CPU because It executes the POST and the startup chime. xx(

 

[Renegade]

Those B&W mobos are a pain to get back to work

Try unplugging both IDE cables, push 15+seconds on the pram button, etc...

Keep on trying various things, it may eventually come back to life but you won't undertand why (no one can)

 

[max1zzz]

just keep resetting the pram and pokeing around with it, eventually it will decide to work again

might also be worth unplugging everything, removeing the pram battery and leaveing it for a day or two, this got mine fireing again once (mine has done this 2 or 3 times)

 

[yntzl]

Those B&W mobos are a pain to get back to workTry unplugging both IDE cables, push 15+seconds on the pram button, etc...

Keep on trying various things, it may eventually come back to life but you won't undertand why (no one can)

Thanks for your tips, I did everything that you said, but none of them worked.

just keep resetting the pram and pokeing around with it, eventually it will decide to work again
might also be worth unplugging everything, removeing the pram battery and leaveing it for a day or two, this got mine fireing again once (mine has done this 2 or 3 times)

I'll do that, I disconnected everything externally and internally (IDE, front panel, PSU) and removed the PRAM. I'll let the Mac rest in this way for about two days or so, also, I ordered a new CPU just in case. You said that your Power Mac did this too, and only doing this he booted up again?

Thanks to everyone.

 

[Andropov]

I doubt this is a bad cpu. To toast the CPU you'll need to increase the voltage. When you overclocked it (I assume you just changed the jumper settings) you didn't change the voltage to the CPU core, therefore, it won't overheat. You are just stressing it a bit, but that definitely won't heat the CPU enough to damage it.

I have a G3 B&W with a 300Mhz processor upgraded to 450Mhz, and I never had a problem with it. I also have a PowerMac G4 PCI (Yikes) with a 400Mhz G4 running at 450Mhz. One day it just stopped booting. I tried everything with no luck. I left it unplugged during the night (I removed the battery). Next day, I started it up, zap the PRAM and it booted fine, something I had already tried the night before like one thousand times. So keep trying and it may come back. The fact that it makes the boot sound is a good sign.

PS: Does it boot to open firmware? Cmd+Alt+O+F (I think) Or, at least, do the fans start spinning?

The mobo also has a few confirmation LED's, look if they're all on. You can try booting without any RAM installed to see if it does the 4 beep sound warning there's no RAM installed.

 

[yntzl]

I doubt this is a bad cpu. To toast the CPU you'll need to increase the voltage. When you overclocked it (I assume you just changed the jumper settings) you didn't change the voltage to the CPU core, therefore, it won't overheat. You are just stressing it a bit, but that definitely won't heat the CPU enough to damage it.
I have a G3 B&W with a 300Mhz processor upgraded to 450Mhz, and I never had a problem with it. I also have a PowerMac G4 PCI (Yikes) with a 400Mhz G4 running at 450Mhz. One day it just stopped booting. I tried everything with no luck. I left it unplugged during the night (I removed the battery). Next day, I started it up, zap the PRAM and it booted fine, something I had already tried the night before like one thousand times. So keep trying and it may come back. The fact that it makes the boot sound is a good sign.

PS: Does it boot to open firmware? Cmd+Alt+O+F (I think) Or, at least, do the fans start spinning?

The mobo also has a few confirmation LED's, look if they're all on. You can try booting without any RAM installed to see if it does the 4 beep sound warning there's no RAM installed.

Thanks for your attention, the machine don't boot to open firmware, in fact it doesn't respond to any keyboard commands (for example CMD+OPT+P+R to reset the PRAM or C to boot from CD). I'll report here exactly what the machine does looking thought the motherboard LEDs, the current machine config is: 256MB RAM PC100 on the J19 slot, 160GB on cable select mode on ATA/33 channel, DVD-RW and Zip 100 on the other channel (ATA/16 I think), processor on stock speed (350MHz with thermal compound) and ATI Rage 128 on the 66MHz PCI slot.

Starting up the Mac with everything plugged and with the PRAM battery on:

-Machine turns up

-Fans start to spin

-Startup chime loud and clear

-HD spin up

-DVD-RW turns on

-DS1 LED (ATA activity) turn on for a few seconds and turn off

-DS4 and DS5 LED (USB +5V) both off

-DS6 (Ultra ATA) turn and stays on

-DS7 and DS8 (Power indicator) both synchronized, both on

-DS9 (CPU BUS request) flash for a few seconds and turns off

-Computer stays on and no video

Starting up the computer after left everything internally (PSU, ATA, front panel, etc...) and externally disconnected and the PRAM out for 10 minutes.

-Connected everything internally

-PRAM battery back in

-Pushed CUDA button for 15 seconds

-Connected peripherals and power cable

-Machine turns up

-Fans start to spin

-Startup chime loud and clear

-HD spin up

-DVD-RW turns on

-DS1 LED (ATA activity) turn on for a few seconds and turn off

-DS4 and DS5 LED (USB +5V) both off

-DS6 (Ultra ATA) turn and stays on

-DS7 and DS8 (Power indicator) both synchronized, both on

-DS9 (CPU BUS request) flash for a few more seconds

-Mac beeps 3 times

-DS9 LED turns off

-Computer stays on and no video

I also did this test by changing the memory module and slot and left the ATA cables disconnected, but the results are the same. xx(

 

[TheMacGuy]

3 beeps = No RAM banks passed memory testing

Try using known good RAM. If it still doesn't boot, it could be a bad RAM slot(s).

 

[yntzl]

3 beeps = No RAM banks passed memory testing

Try using known good RAM. If it still doesn't boot, it could be a bad RAM slot(s).

I know that, I've tested all the banks with some modules and the problem persists, also, I'm pretty sure that the module now installed is good because the Mac did booted with this memory before. I think that is the logic board that still need to be discharged, the Mac has passed 12 hours disassembled and away from a plug, I'll let the computer stay on this state for at least more 24 hours.

 

[Andropov]

The whole logic board should be discharged in a few minutes top. But you never know for sure.

When you plug it again, look if the USB keyboard is receiving power. The light on the "Block Caps" key on Apple USB Keyboard turns on for a second when the computer starts up. I think that's why these PowerMacs often miss keyboard combinations at start.

Also try turning on the computer with no RAM modules installed. It should beep four times.

 

[yntzl]

The whole logic board should be discharged in a few minutes top. But you never know for sure.
When you plug it again, look if the USB keyboard is receiving power. The light on the "Block Caps" key on Apple USB Keyboard turns on for a second when the computer starts up. I think that's why these PowerMacs often miss keyboard combinations at start.

Also try turning on the computer with no RAM modules installed. It should beep four times.

Alright, I'll observe that, and the four beeps means that the ROM block is bad, right? The one beep means that no RAM is installed according to the service manual.

 

[mcdermd]

Have you tried removing the PRAM battery altogether? I know the G4 PowerMacs will not boot with a flat PRAM battery but are just fine without one at all. It was a fast trick for "reviving" "dead" PowerMacs.

 

[Andropov]

Four beeps means there's a problem with the logic board, although I don't know which one it is. According with Apple manuals, it means "Bad checksum for the remainder of the boot ROM ". That doesn't mean a problem with the boot ROM, but a problem in the verification test each system runs in each boot. Verify you've placed the jumper block properly, that might cause the problem. Maybe one of the jumpers you were using for the overclock is broken. If you're using the original block of jumpers, you shouldn't have that problem.

 

[yntzl]

Have you tried removing the PRAM battery altogether? I know the G4 PowerMacs will not boot with a flat PRAM battery but are just fine without one at all. It was a fast trick for "reviving" "dead" PowerMacs.

Even booting without the PRAM battery the problem persists, a few seconds after the startup chime the Mac beeps 3 times, I tested with six modules of RAM in every slot, and I don't think that all of them are bad.

Four beeps means there's a problem with the logic board, although I don't know which one it is. According with Apple manuals, it means "Bad checksum for the remainder of the boot ROM ". That doesn't mean a problem with the boot ROM, but a problem in the verification test each system runs in each boot. Verify you've placed the jumper block properly, that might cause the problem. Maybe one of the jumpers you were using for the overclock is broken. If you're using the original block of jumpers, you shouldn't have that problem.

The pins and the original block of jumpers are fine, and visually there is no sign of problems on the motherboard.

I ordered a new CPU, when it arrives I'll test again and if the system don't boot up, I'll need a new logic board.

 

[yntzl]

Well... the problem was on the logic board.

I bought a new board and I installed on the Mac using the same processor and memory and everything worked fine.

Thanks to everyone who tried to help!

 

[Schmoburger]

Yosemite architecture boards are notoriously temperamental and very sensitive to things such as poor ram, dusty connectors, PRAM battery issues, overclocking.... just about everything. I've owned 3 G3's... two Rev. 1 and one Rev. 3, and still have one of each, and a Yikes G4 which is essentially rev. 3 of the Yosemite logic board... It's near identical to the rev.2 except for the deletion of ADB and the inclusion of a G4 CPU boot enabler.... or more to the point a lack of a G4 boot disabler. Yep... they actually did that from what Ive read. Thanks Apple.

But yeh, I've played with em, overclocked em, modified them etc for over 10 years and all have given me headaches after altering configurations. My Yikes just tonight decided not to power on from the front button, which it and my Rev 2 G3 periodically do, meaning I have to drop the side and power it on with the button on the logic board. And then there are all the bootup issues... Nearly everytime ive changed a processor in one of them, or played with basic CPU clock settings, even sometimes just swapping out RAM for other RAM, I get a bong and no display startup, no boot sequence and a series of beeps, or power-on and then nothing. I worked out tho in a moment of pissed off desperation after one of my early attempts at a CPU overclock, that half the time its simply a matter of powering on with the cuda button held in until you hear a low-pitched, protracted "boooooooop" sound from the speaker (unless you shorted your onboard speaker once like I did so it no longer works), it should restart and bong, afterwhich you zap the PRAM a few times with Ctrl+Cmd+P+R and then allow it to boot... display will usually show and itll look for a drive and boot up, even tho it seemed 5 minutes earlier to be cactuar.

Thats actually how I procured my Rev. 1... me and a mate who were student admins were asked to build it up for my school 10 years ago as a hot video editing machine with G4 upgrade, big drives, max RAM etc. It was a temperamental, unstable lemon, partly due to the crap rev.1 IDE controller giving corruption issues, and partly as it turned out due to somebody using the 300mhz heatsink and not regreasing it causing it to overheat, and saw little use until it wouldnt boot one day and was put in a cupboard. My brother ended up with it sometime later and couldnt get it to work...so i convinced him to give it to me. After I pieced it back together, it wouldnt boot, but after some particularly frustrating mollycoddling and perserverance as above, and a few different combo's of RAM, even that one is now a functioning stable machine, with the stock 350mhz CPU out of my Yikes in it (as it still as the old Sonnet enabler flashed to the firmware) clocked to 400.