Need help solving problem with HK1400 Amplifier - RH channel no sound
Having replaced faulty components in the stabilised supply to the preamplifier section of this Harman-Kardon amplifier, I found that the RH Channel was quiet, then discovered that the voltage on the collectors of Q414 &434 was at +27v instead of the +12v on the corresponding point in the working channel. None of the fusible resistors(R418,430, 442, 428, 444, etc., etc., were o/c or otherwise faulty, and all relevant transistors check out OK 'cold'. The rail voltages are correct, and the centre voltages measured wrt ground at R452/452 are virtually zero, so no DC offset. Can anyone suggest what component(s) may be responsible for this fault, which results in very quiet sound if a 1kHz s/w signal is injected at any early stage in the circuit, please?