Harman Consumer Group AVR75/85, Technical Manual

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3. All Clear
This service program can clear all memorized operations and functions. With the POWER ON , press the “ CD ” button while
pressing the “ MODE s ” button for more than 3 seconds. FLD shows “ CLEAR MEMO ” and power will be OFF .
II. ELECTRICAL ADJUSTMENT
1. Main amp idling current adjustment.
1) With the power OFF , set variable resistor R755 (Lch), R756 (Rch) RH28 (Center ch) on the PC board ( P704 ) to the
center position.
2) Locate test points J723 (Lchan) J724 (Rchan) and J725 (Centerchan). These are 3 pin female molex connectors on the
MAIN PCB. Attach a DC voltmeter (set to a low range) to the two outer pins on each test point. This is best accomplished
by making up a “test plug” using a male molex connector that fits into the one in the unit, with wires attached, for
connection to the voltmeter. An alternate method is to use two “mini-grabbers” to attach to the two outer pins on each
connection. The middle pin has no connection.
3) After the above, adjust the idling current as follows: Turn the power ON and adjust variable resistor R755 (Lch), R756
(Rch), RH28 (Center ch) while observing the reading on the voltmeter.
*The target value is 11mV (25 mA).
NOTE:
When a unit whose idling current has been adjusted is switched on after 1 minute it reaches about 4.7~5.5mV. After 30
minutes, it reaches a balanced state and stabilizes at 8.9-11mV (target). Therefore, if the adjustment is made 30 seconds
after the power is switched on, adjust to 3.5 ~ 4.0mV. In the same way, if 1 minute has passed since the power was
switched on, adjust to 4.7 ~ 5.5mV. From 1 to 2 minutes, adjust to 6.2 ~ 6.4mV. From 2 to 4 minutes, adjust to 7.1 ~
7.6mV. From 4 to 7 minutes, adjust to 7.9 ~ 9.0mV. After more than 7 minutes since the power was switched on, adjust to
the setting of 10.5 ~ 11.2mV. Here is a reference table for the adjustment values:
Time since power switched on Idling current adjustment
30 seconds 3.5 ~ 4.0mV
1 minute 4.7 ~ 5.5 mV
1 - 2 minutes 6.2 ~ 6.4mV
2 - 4 minutes 7.1 ~ 7.6mV
4 - 7 minutes 7.9 ~ 9.0mV
More than 7 minutes 10.5 ~ 11.2mV
III. ALIGNMENT PROCEDURES
Test Equipment Required
1) AM/FM Signal Generator
2) Video Signal Generator
3) Digital Multimeter
4) Distortion level meter
1. AM IF Adjustment
Step
Input Signal Source
Connection
Signal
Frequency
Source Signal Output Level
and Modulation
Reception
Frequency
Adjustment
Point
Adjustment
Value
1
Signal generator output to
transmission loop antenna.
(:Standard required loop)
999 KHz
(Europe)
1000 KHz
(USA)
Level 300
m
V/m (50dB/m)
Mod. 400 Hz 30%
Tuning point LA06
Output level
(L or R)
Maximum
at TAPE-OUT
REMARK: For receiving antenna, the one supplied with the unit is adequate.
This adjustment is not normally necessary, because the coil LA06 is preset by the original supplier.
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Harman Kardon
Dolby Digital Audio/Video Receiver
AVR75/85