Try unplugging the Onkyo for 60 minutes, then plug back in and try it again. This will reset the processor and hopefully the unit will operate normally. If it does'nt, try disconnecting all the speaker and cycle the power off, then on again. If you still have "pretect" on the acsreen with no load connected, then the unit has a bad output transistor, or capacitor and is in need of service.
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The parts are not impossible to find. Almost every chip, cap and resistor in the circuit can be cross referenced with a sub of equal specs at www.digikey.com.
Would you like me to send you the contact info for an Onkyo Service Center?
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