Sansui AU-X1 Service Manual page 12

AU-Xl
4. ADJUSTMENTS
Notes: 1. Level Volume . . . . . . . . . . . . . . Minimum
2. Room Temperature .. .. . . . . . . 18°C - 28°C
(65° F - 83° F)
3. When replacing some parts or circuit board, refer to
description in REMARKS.
4. For th is adjustment , run the unit for more than ' 3
minutes after the power is switched ON .
4-1. F-2778 Power Supply Voltage Adjustment (See Top View on page 12)
STEP
SUBJECT
MEASURE
ADJUST
ADJUST
REMARKS
OUTPUT
FOR
1 For MC Head Between GND & VR03 -10.5 V
F· 2778
AmpL-CH TP01 F-277 8
2 For MC Head Between GND & VR04 -10.5 V
r - -
( TPOl - TP04)
Amp R-CH TP02 F-277 8
ffi
3 For MM Head Between GND & VR01 - 47 .5 V
+
-
Amp L-CH TP03 F-2778
~
4
For MM Head
Between GND & VR02 -47.5 V
Amp R-CH TP04 F-2778
(Cha ss Is) •
4-2. F-2775 Driver Circuit Adjustment (See Top View on page 12)
STEP SUBJECT
1 DC OV Adj.
L-CH
2 DC OV Adj .
R-CH
3 Bias current
Adj .
L-CH
.
4 Bias current
Adj.
R-CH
MEASURE OUTPUT
Speaker terminal
Speaker term inal
Between emitters of power
transistors, TR701 & TR70 3
(between T.P Pin)
Between emitters of power
transistors, TR702
&
TR704
(between T .P Pin)
ADJUST
VR01
F-2 77 5
VR01
F-277 5
VR02
F-2 77 5
VR0 2
F-2775
ADJUST FOR REMARKS
DC OV ± 5 mV Before turning ON power switch , set
VR01 to center position.
DC 25 mV ±1 mV Before turning ON power switch,
turn VR0 2 fully counterclo ckwise.
This bias current adjustment con-
verts current value into voltage by
Ohm's law.
4-3. F-2917, F-2918
MC Head Amp Adjustment (See Top View on page
12)
STEP SUBJECT
MEASURE OUTPUT
ADJUST
ADJUST FOR REMARKS
1 DC OV Adj. Between GND & common VR01 DCOV±5mV
Before turning ON power switch, set
L-CH F-2917
joint of emitter resistors F-2917
VR01 to center position.
R41, R47 (TP01)
2
DC OV Adj . Same as above
VR01
R-CH F-291 8 F-29 18
4-4. F-2770, F-2771 Equalizer Circuit Adjustment (See Top View on page 12)
STEP SUBJECT MEASURt OUTPUT ADJUST ADJUST FOR REMARKS
1 DC OV Adj. Between GND & common VR01
DC OV ±50 mV
Before ll!rning ON power switch , set
L-CH F -2770
joint of emitter re sistors
R38 , R39 (TP01)
F-2770
VR01 to center position.
2
DC OV Adj.
Same as above VR01
R-CH F-2771 F-2771
4-5. F-2819
Flat Amp Circuit Adjustment (See Top View & Bottom View on page
12)
STEP
SUBJECT
MEASURE OUTPUT
ADJUST ADJUST FOR
REMARKS
1 DC
ov
Adj . Between chassis and collector VR01
DCOV ±5mV Before turning ON power switch, set
L-CH connect ing point TP01 of F-2 819
VR01 & VR02 to center position.
TR15 & TR17 (Top View)
2 DC OV Adj. Between chassis and collector VR02
R-CH connecting point TP02 of
TR 16 & TR 18 (Bottom View)
F-2819
11