R74 & R84-10 ohm .25 watt. They carry the Rail voltages to the +/-15 volt regulated supply. Check Q23-D669 and Q28-B649 and associated components. Also, Check for any shorted opamps on the preamp/xover board.
There is a shorted opamp. Desolder Pins 4 and 8 of each opamp, starting with U8. After each opamp recheck with an ohmmeter to see if the resistance returns to normal,should be megohms. There will must likely be several failed opamps.
