Sony TA-N1 - Manual (Page 7)

TA-N1
7 7
SECTION 4
DIAGRAMS
SECTION 3
ELECTRICAL ADJUSTMENT
BIAS CURRENT ADJUSTMENT
• As the voltage changes according to the time the power is sup-
plied, adjust correctly according to the following procedure.
Connection:
4-1. CIRCUIT BOARDS LOCATION
MAIN L board
MAIN R board
INPUT board
PS B board
AC/PS board
AC SW board
LED board
Procedure:
1. Measure the voltage at the five measuring points just after sup-
plying the power, and adjust RV301 (L-CH) and RV401 (R-CH)
so that the measuring point with the lowest voltage becomes
approx 15 mV.
Measuring Point Adjusting Point
L-CH Between the 5 measuring points
(+) TP301, TP302, TP303, RV301
TP304, TP305 and TP306 (–)
R-CH Between the 5 measuring points
(+) TP401, TP402, TP403, RV401
TP404, TP405 and TP406 (–)
Digital voltmeter
MAIN-L, R boards
TP301 to 305 (L-CH), TP401 to 405 (R-CH)
TP306 (L-CH), TP406 (R-CH)
2. Leave for one hour with the power supplied. (Aging)
3. Measure the voltage at the respective measuring points and ad-
just RV301 (L-CH) and RV401 (R-CH) so that the voltages be-
come within the ranges shown in the following table. Adjust to
the voltage with the highest priority shown in the table as much
as possible.
Priority Order Adjusting Value
1st (Highest priority) 19.8 mV to 22.0 mV
2nd 19.8 mV to 24.2 mV
3rd 18.7 mV to 24.2 mV
4th 18.7 mV to 25.2 mV
5th 15.0 mV to 25.2 mV
4. Leave for another 30 minutes if the adjustment control has been
rotated.
5. Measure the voltage again and check that it is within the adjust-
ing value. If outside, repeat from step 3 again.
6. Be sure to perform aging for more than 30 minutes if the adjust-
ment control has been rotated. Finally check the voltage before
ending the adjustment.
THIS NOTE IS COMMON FOR PRINTED WIRING
BOARDS AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed
in each block.)
For schematic diagrams.
Note:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ω and 1 / 4 W or less unless otherwise
specified.
• % : indicates tolerance.
• 2 : nonflammable resistor.
• 5 : fusible resistor.
• C : panel designation.
• S : B+ Line.
• T : B– Line.
• H : adjustment for repair.
• Voltages and waveforms are dc with respect to ground in
playback mode.
• Voltages are taken with a VOM (Input impedance 10 M Ω ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
F : AUDIO
Note:
The components identi-
fied by mark
! or dotted
line with mark ! are criti-
cal for safety.
Replace only with part
number specified.
Note:
Les composants identifiés par
une marque
! sont critiques
pour la sécurité.
Ne les remplacer que par une
piéce portant le numéro
spécifié.
For printed wiring boards.
Note:
• X : parts extracted from the component side.
• ® : Through hole.
• b : Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
Caution:
Pattern face side: Parts on the pattern face side seen from the
(Side B)
pattern face are indicated.
Parts face side: Parts on the parts face side seen from the
(Side A)
parts face are indicated.