Actually this was a Quadra 605, but mainboards are the same.
On this board 4 of the VIA's around C137 were toast:
SPKR- feed to the TDA7052AT Amp
12V supply to the TDA7052AT Amp
VIA's that connect U30-24 to Sys_Reset
SPRK- was bodged to a trace underneath the board that was scraped away so I...