Electrical Adjustments - Sony TA-F448EB Service Manual

BIAS ADJUSTMENT
Adjustment Procedure:
1. Rotate fully the bias adjusting semi-fixed resistors (RV301 (L-
CH), RV351 (R-CH)) to the minimum position (counterclock-
wise).
2. Connect a digital voltmeter to the CN406 (L-CH) and CN407
(R-CH).
pin 1 pin 3
CN406 (L-CH) –
CN407 (R-CH) +
3. Set the slidack to 0 V AC, and press the POWER button (ON)
on the set.
4. Raise gradually the slidack voltage up to the rated voltage (230
V AC).
5. At this time, confirm that the speaker relay is turned on (it will
click).
6. Adjust the RV301 (L-CH) and RV351 (R-CH) so that a reading
of digital voltmeter is from 10 mV to 20 mV.
7. Return the slidack to 0 V AC, and press the POWER button
(OFF) on the set.
SECTION 3
ELECTRICAL ADJUSTMENT
+
–
digital voltmeter
+
–
Connection and Adjustment Location:
BIAS
Adjustment
[MAIN (B) BOARD] – Component side –
CN407
3
1
C459
1 3
CN406
– 7 –
[MAIN (A) BOARD]
– Component side –
C372 C322
RV351
(R-CH)
RV301
(L-CH)
C409