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9
XM-460GTX
Bias Adjustment
Note : The Bias adjustment should be performed only if any of
Q109 and Q110 for RV104, Q209 and Q210 for RV204,
Q309 and Q310 for RV304, and Q409 and Q410 for RV404
are replaced.
Q309 and Q310 for RV304, and Q409 and Q410 for RV404
are replaced.
Setting :
Procedure:
1. Rotate variable resistors RV104 (FRONT L-CH), RV204
1. Rotate variable resistors RV104 (FRONT L-CH), RV204
(FRONT R-CH), RV304 (REAR L-CH) and RV404 (REAR
R-CH) full clockwise as seen from the pattern side to minimize
the bias current.
R-CH) full clockwise as seen from the pattern side to minimize
the bias current.
2. The input signal is with no signal.
3. Connect the stabilized power supply between B+ and REM
3. Connect the stabilized power supply between B+ and REM
terminals and gradually increase the voltage to 14.4 V while
checking for any abnormal current.
checking for any abnormal current.
4. Adjust RV104 (FRONT L-CH), RV204 (FRONT R-CH), RV304
(REAR L-CH) and RV404 (REAR R-CH) so that the digital
voltmeter connected between the respective test points reads
6±1 mV.
voltmeter connected between the respective test points reads
6±1 mV.
5. After this adjustment, verify that the current value of the
stabilized power supply is 1.4 to 1.8 A.
SECTION 3
ELECTRICAL ADJUSTMENT
+
_
stabilized
power supply
digital
voltmeter
B+, REM terminals
set
GND terminal
test points
Adjustment Location :
RV Ref. No.
Test points
RV104
TP11 and TP12
RV204
TP21 and TP22
RV304
TP31 and TP32
RV404
TP41 and TP42
TP32
TP22
TP21
TP11
TP12
TP31
TP41
TP42
RV404
BIAS ADJUSTMENT
(REAR R-CH)
RV104
BIAS ADJUSTMENT
(FRONT L-CH)
RV204
BIAS ADJUSTMENT
(FRONT R-CH)
RV304
BIAS ADJUSTMENT
(REAR L-CH)
– MAIN BOARD (CONDUCTOR SIDE) –
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