AVR 1550 - Harman Kardon Audio Service Manual (repair manual). Page 3

TROUBLESHOOTING GUIDE 

In the rare case where the unit’s operation or the
displays seem abnormal, the cause may involve
the erratic operation of the system’s memory or
microprocessor.

To correct this problem, first unplug the unit from
the AC wall outlet and wait at least three min-
utes. After the pause, reconnect the AC power
cord and check the unit’s operation. If the system
still malfunctions, a system reset may clear the
problem.

To clear the 

AVR 1550’

s entire system memory

including tuner presets, output level settings,
delay times and speaker configuration data, first
put the unit in Standby by pressing the System
Power Control button 2. Next, press the
Tone Mode 6 and the RDS @ buttons simul-
taneously.

The unit will turn on automatically and display
the R E S E T message in the Main
Information Display M. Note that once you
have cleared the memory in this manner, it is nec-
essary to re-establish all system configuration
settings and tuner presets.

NOTE: Resetting the processor will erase any
configuration settings you have made for speak-
ers, output levels, surround modes, digital input
assignments as well as the tuner presets. After a
reset the unit will be returned to the factory 
presets, and all settings for these items must be
reentered.

If the system is still operating incorrectly, there
may have been an electronic discharge or severe
AC line interference that has corrupted the 
memory or microprocessor.

If these steps do not solve the problem, consult
an authorized Harman Kardon service depot.

Unit does not function when 

• No AC Power

• Make certain AC power cord is plugged 

Main Power Switch 1 is pushed

into a live outlet

• Check to see if outlet is switch controlled

Display lights, but no sound 

• Intermittent input connections

• Make certain that all input and speaker 

or picture

connections are secure

• Mute is on

• Press Mute button 

2

• Volume control is down

• Turn up volume control

Sound is heard, but Front-Panel

• Display brightness is turned off

• Follow the instructions in the Display Brightness section 

Display does not light 

on page 23 so that the display is set to VFD FULL

No sound from any speaker;

• Amplifier is in protection mode

• Check speaker-wire connections for shorts at receiver 

light around Power switch 2 is red

due to possible short

and speaker ends

• Amplifier is in protection mode 

• Contact your local Harman Kardon service depot

due to internal problems

No sound from surround or 

• Incorrect surround mode

• Select a mode other than Stereo

center speakers

• Incorrect configuration

• Check speaker mode 

• Stereo or Mono program material

• With (analog or digital) Dolby surround modes, the surround 

decoder may not create rear-channel 
information from non-encoded programs

• Speakers not properly connected

• Check speaker-wire connections or use test tone

to verify connections (see page 18)

Unit does not respond to 

• Weak batteries in remote

• Change remote batteries

remote commands

• Wrong device selected

• Press the AVR selector 

5

• Remote sensor

5

is obscured

• Make certain front-panel sensor is visible to remote or 

connect remote sensor

Intermittent buzzing in tuner

• Local interference

• Move unit or antenna away from computers, fluorescent lights,

motors or other electrical appliances

Letters flash in the Channel Indicator

• Digital audio feed paused

• Resume play for DVD

Display P and Digital Audio stops

• Check that Digital Signal is fed to the Digital Input selected