Harman Kardon HK680 - Technical Specifications; Power and Performance Ratings; Input Sensitivity and Overload

This unit is designed for trouble-free
operation; most problems users
encounter are due to operating errors.
So if you have a problem, first check this
list for a possible solution. If the problem
persists, consult your authorized
Harman Kardon service center.
TROUBLESHOOTING
If the problem is:
Make sure that:
No lights illuminate when power cord is
plugged into AC outlet.
M@ The unit is plugged into a live outlet.
No sound is heard.
@ Press the Speakers switches corresponding to the desired speakers.
@ Correct Listen button has been pressed.
@ Volume is turned up.
m@ Speaker wires are connected properly.
@ Hook-up wires to source component are connected properly.
Sound is not heard from the speaker system
on one side.
When listening to stereo sound, the left and
right sounds are reversed.
Intermittent or continuous buzzing or hissing.
@ The speaker wires and connection wires are connected correctly.
M@ The balance control knob is set to the center.
M™ The speaker wires are connected correctly.
@ The wires between components are connected correctly.
M@ The unit is away from fluorescent lights, TVs, motors and other electrical
appliances.
Tone control is not functioning.
M@ Press the Tone Defeat switch to off position.
Phono sound is too faint, has hum, ringing,
or “howl”.
Ground wire from turntable has been connected to ground terminal on amplifier.
@ Cable from turntable is away from power cords and speaker cables.
M@ Turntable is away from speakers.
@ Turntable is on stable surface.
Note: The optional phono board is required to play a turntable.