Harman Kardon HK6900 - Troubleshooting Common Issues; Power and Protection Light Problems; Sound Output and Source Connectivity Issues

Troubleshooting
If your HK6800 or HK6900 does not operate as
expected, first check the items in the following list. If
you cannot determine the source of the problem, contact
your dealer or authorized Harman Kardon service
representative.
No lights on the front panel.
1. Power cord is not plugged into power outlet.
2. Wall outlet or extension cord is faulty. Check for
poor connections and/or blown fuse.
3. Breaker on plug strip has tripped. Reset breaker.
The PROTECT light goes on and stays on
1. The unit is overheated. Make sure that the unit is
receiving adequate ventilation. Also check to make sure
that the SPEAKER OPERATING MODE switch is set to 4Q
if you are using 4-ohm speakers (using the 8Q setting with
4-ohm speakers can cause overheating). Be sure you give
the unit adequate time to cool off; the PROTECT light will
remain on until the unit is cool enough to operate safely,
which may take 60 to 90 minutes. Your amplifier will cool
off more quickly if you turn off its power switch.
2. Speaker wires are touching one another, causing a
short circuit that activates protection circuits that shut
down the amplifier. Check the speaker wires.
3. If you have ensured that the unit is not overheated
and even with the speaker wires completely disconnected,
the PROTECT light still remains on, take the unit to an
authorized Harman Kardon service center for service.
No sound.
1. Speakers are connected to wrong set of speaker
terminals.
2. SPEAKER selector is not switched to correct set of
speakers.
3. Speaker wires are touching one another, causing a
short circuit that activates protection circuits that shut
down the amplifier.
4. FUNCTION selector has not been switched to the
source currently playing.
5. VCR/TAPE MONITOR selector is switched to 1 or 2
while the source currently playing is CD, PHONO, TUNER,
AUX or A/V. Switch VCR/TAPE MONITOR selector to
SOURCE.
No sound from tape deck or VCR
1. VCR/TAPE MONITOR selector has not been
switched to the correct unit.
2. Tape deck or VCR is plugged into the wrong set of
input jacks.
3. Output of tape deck is plugged into OUT on back of
amplifier. Plug OUT on tape deck into IN on amplifier.
Turntable sound is extremely faint
l.Turntable has been connected to wrong set of input
jacks. If turntable has a moving magnet cartridge, connect
cables to the PHONO MM jacks; if turntable has a moving
coil cartridge, connect cables to PHONO MC jacks.
Low-pitched hum or buzz from turntable
1. Ground wire from turntable has not been connected
securely to ground terminal on amplifier.
2. Cable from turntable is too close to power cords or
speaker wires.
3. Tiny wires connecting cartridge to turntable arm are
not firmly connected.
Low frequency oscillation or "howling" when playing
turntable
1. Too much bass boost is being applied. Turn off
LOUDNESS and/or reduce amount of BASS tone control
boost. Turn on the SUBSONIC filter.
2. Turntable is too close to speakers.
3. Turntable is placed on unstable surface.
Speakers lack bass
1. Polarity of one speaker has been reversed. Check
speaker wires and ensure that the + terminal on the
amplifier is connected to the + terminal on the speaker.
Sound quality of tuner is poor
1. Tuner’s antenna is not connected or is not positioned
properly.
Tone control is not functioning
1. The TONE DEFEAT switch is on, bypassing the
tone controls.
2. The MAIN DIRECT switch is on, bypassing the
tone controls.
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