In working as well as non working board its same, I see a wave and a 66MHz frequency.
Try to stop it as I described above (you can unsolder it) and watch the beep. On working board.
I have a question.
What do these two LEDs do? (Please see the picture below.)
Also don't forget to stop CPU clock (66MHz) and check the beep sound.
PS
At the bottom picture you will find some curves explanation.
Red Led is blink at startup power on, it also keep on glowing if the voltage is less than 4v, regarding other uses not sure.
Green Led refers to the ok board, If it glows continuosly, not bright nor dim, then the motherboard is ok.
Still, i need more details on stopping to those CLOCK signals, desolder is not possible i guess, Maybe any other options.
As for the Pics, Yeah the BIOS is not getting input signals to process so BIOS not loading in non working board i guess.