Power Mac G3 beige - startup chimes but no boot

[Aektann]

I’ve took a new motherboard for my PowerMac G3 Beige desktop. It was in a great cosmetic condition, but has a booting problem. When I press the power button, the computer starts with the boot chime and I see a mouse cursor on the screen, but no disk icon appears and the board does not attempt to boot from either HDD, or floppy drive.
I tried to press the CUDA reset button, but it didn’t help. What should I check first?

 

[Byrd]

RAM, single stick known good, check PSU voltages as well

 

[alectrona6400]

There could be a possibility that the capacitors are starting to go bad. I used to have a 7300 several years ago and decided to dishwash the board which got it working again, but when I tried to power it on months later the issue came back. Parted out the machine anyway considering it was not in good shape. PSU could also be the culprit, but I know these computers are coming onto 27 years old.

 

[Aektann]

I will try to replace capacitors tomorrow and see if it helps, thanks you!

 

[Byrd]

Yes, but do the usual troubleshooting before desoldering things?

 

[Unknown_K]

Beige G3's can use a standard PC ATX supply if you change a jumper on the motherboard.

I have a Beige G3 desktop that hasn't worked since I got it more than a decade ago. Since I have others, I never bothered with it but someday I do need to get it working. Wish I had a diagnostic card like I have for PCI PC's so I could see where it hangs up or if it even does anything. You can have capacitor rot, bad PS, bad voltage regulator, bad G3 chip or wrong jumpers, dead ROM, all kinds of possibilities.

 

[Aektann]

Well, I have the second working motherboard, which is the same model. Actually I am transferring everything from it to check this one.

 

[alectrona6400]

Yes, it would be a good idea to test other components before jumping to the recap, my bad. Should've mentioned that. Wouldn't be a bad idea though considering the age of the machine.

 

[Dude.JediKnight]

My Beige G3 has been having problems as well, but I need to find time to fully diagnose the cause. I don’t have a second machine available to swap parts, so I’m hoping I can find someone to team up with at a future Repair Workshop. I fear it’s bad caps, but as mentioned above, there are many other possibilities to rule out first.