harman/kardon
TECH TIPS
Troubleshooting tips and solutions to common service problems
TIP# HKTT2004-03
Isolating audio problems in an AVR receiver
Using 6/8 Direct In
The following charts are used to help the tech quickly isolate
audio problems in an AVR receiver. Use the following
procedures to help find what is working, then to quickly locate
the problem area.
Equipment needed:
9
1 set of (RCA) Y adaptors.
9
Function/signal generator.
9
Oscilloscope.
Models covered:
AVR210 AVR310
AVR220 AVR320
AVR520 AVR225
AVR125 AVR525
AVR130 AVR230
AVR330 AVR430
AVR630
Procedure:
1)
Do a factory reset of the receiver. (This will eliminate any common micro processor
problems.) Reset List can be found near the last page or check the service
website; www.harmanservice.com for the latest info.
2)
Print the block diagram from the service manual.
3)
With no inputs or speakers attached to the AVR turn on the receiver and turn the
volume all the way down.
4)
Turn unit off.
5)
Hook up an oscillator to the 6/8 Direct in jacks using the Y adaptors. Adjust the
oscillator to about 0db (.775Volts RMS).
6)
Hook up an oscilloscope to monitor the line out jacks. Or, if there are no line out
(preamp out) jacks monitor the input to the power amps or the speaker outs.
(AVR125, 225, 130 do not have preamp out jacks)
7)
Turn the AVR on. Select 6 or 8 direct in, depending on the receiver.
8)
Slowly turn the volume control up until you can easily measure the voltage at the line
out jacks. ( -40 to -25db )
Harman Consumer Group 250 Crossways Park Dr. Woodbury, New York 11797
Email [email protected]
