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xkola12345x

macrumors newbie
Original poster
May 27, 2021
4
0
I've recently acquired a B&W Rev.B Power Mac G3. I used to have one back in the day, and wanted to relive some memories. I know these machines can sometimes behave in wired ways, but after going through many troubleshooting procedures I'm honestly out of ideas.

I bought it, but due to covid restrictions seller shipped it to me. Before buying I got the video of the system running Mac OS X 10.4.11 Tiger, but as agreed with the seller, the system came without HDD for privacy reasons.
Tech Specs:
400Mhz CPU overclocked to 450Mhz
1GB RAM
ATI Radeon 7000
DVD-ROM Drive
USB 2.0 PCI Card (removed for troubleshooting)

When I got the computer I tried booting it of the original restore CD (it is Mac OS 8.6 restore CD for Power Mac G3) for the system that I had lying around, but without any luck. Holding C as written on the CD doesn't make a difference.

Troubleshooting already done:
I basically followed this thread, but without success.
From service manual, that I attach I did the following procedures:
1 Check video cable/card connections.
2 Check jumper block configuration at J25. (Tried underclocking to 400Mhz and 350Mhz with no luck, though old hard drive jumpers I had lying around seemed a bit too wide).
3 Reset Cuda chip.
4 Reset logic board. (I'm not 100% sure I performed it correctly)
5 Reseat the video card.
6 Reseat the SDRAM DIMMs.
7 Reseat processor module.
8 Remove all SDRAM DIMMs and try replacing them one at a time to test. (I unfortunately do not have any spare working PC100/PC133 DIMMs)
9 Replace monitor cable

I also removed the PRAM battery and tried repeating this procedure. I know that B&W should boot without it, and will try replacing it later.

From Logic Board LEDs it looks like DS7 & DS8 are in sync, and DS9 lights up during boot up.
I can start the computer using Apple USB Keyboard (M2452 - that one with power button), but there is no power coming to it and Command+Option+P+R yields nothing. DS4 & DS5 don't light up. From my tests, if I plug in keyboard into USB port of the PCI card, its caps lock light lights up for a split second, so it seems that the PCI bus is getting power. I unfortunately don't have an ADB keyboard.

As for DVD drive - I can only open it when its IDE cable is disconnected from the logic board.

Tomorrow I will try to repeat the whole procedure but, apart from it, I'm out of ideas and ask you for help.

Edit:
Link to the manual
 

xkola12345x

macrumors newbie
Original poster
May 27, 2021
4
0
Ok, it's me again. During the weekend I was able to do some further testing and here is what I found.

I was able to test the RAM on my friend's iMac G3 and it looks like it is working. iMac was able to use it without any problems, but when I tried to boot the B&W with only one stick of RAM (I tired with each one), there was no effect, even after CUDA and Logic board resets, but I heard read somewhere, that G3 Power Macs sometimes need a couple of those to get going.

It also seems that the CPU is working, as the heatsink is getting hot when the machine is running.

After all troubleshooting I did, I'm out ideas. Is there anything else I can do to fix the machine, or is it some kind of logic board problem and there is no hope of getting the computer working?
 

Dronecatcher

macrumors 603
Jun 17, 2014
5,249
7,888
Lincolnshire, UK
I can't offer any help only sympathy - the one Powermac G3 I had was so delicate I feared breathing too hard near it...
It was fussy about everything - RAM, hard drives, optical drives, graphics cards, firewire....I was glad to see it go!
 
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