Realistic STA-16B User manual

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Serulce
STA-168
AM/FM STEREO REGEIVER
Catalog Number: 31 -2078
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ELECTRICAL PE RFORMANCE
D ISASSEMB LY I NSTRUCTIONS
DIAL STRINGING DIAGRAM
BLOCK DIAGRAM
ALIGNMENT INSTRUCTIONS ...,.,7_
LEVEL DIAGRAM
SPECIFICATIONS ,3-4
TROUBLESHOOTING
AM/FM TUNER, IF & MPX P.C.B. (TOP & BOTTOM VIEWS)
PRE AMP & TONE CONTROL P.C.B. (TOP & BOTTOM VIEWS)
11-12
13
14
5
5
6
9
10
15
16
MAIN AMP P.C.B.
JACK P.C. B.
POWER SUPPLY P.C.B. (TOP
IC & TRANSISTOR LEAD ID
ELECTRICAL PARTS LIST
(TOP & BOTTOM VIEWS)
(TOP & BOTTOM VIEWS) 15
& BOTTOM VIEWS)
ENT|F|CATION ....... 16
17 -22
23-24
24-25
26-27
MECHANICAL PARTS LIST
IC INTERNAL DIAGRAM
17) SCHEMATIC DIAGRAM
18) EXPLODEDVTEW ...28-29
-2-

1} ELECTRICAL PERFORMANCE SPECIFICATIONS
AM BAND
Frequency Coverage
IF
Antenna Sensitivity for S/N 20 dB
at 600 kHz
at 1000 kHz
at 1400 kHz
Terminal Sensitivity (S/N 20dB)
ACA at S/N 6 dB Sensitivity at 1000 kHz
AGC Distortion at 1000 kHz
1000 mV/m, 80% modulation
AGC Figure of Merit
I F Rejection at 600 kHz
lmage Rejection at 1400 kHz
Distortion at 5 mV/m 30 % modulation 400 Hz
Tape Out Level 5 mV/m 30 % modulation 400 Hz
Fidelity 5 mV/m lnput (1 kHz = 0 dB) -6 dB down
Whistle Modulation of 2nd and 3rd Harmonic
at 1 and 5 mV/m lnput
Calibration Accuracy at 600 kHz
at 1400 kHz
S/N Ratio at 5 mV/m lnput, 1000kHz
FM BAND
Frequency Coverage (For UL AND C.S.A.)
Frequency Coverage (For European and Australian)
IF
IHF Sensitivity at 90, 98 and 106 MHz
S/N Ratio at 1 mV lnput
FM Limiting - 3dB
I F Rejection at 90 MHz
lmage Rejection at 106 MHz
Capture Ratio
ACA t 400 kHz at 100sV
Audio THD 400 Hz, 75kHz Dev.
Calibration Accuracy at 90 MHz
at 106 MHz
AFC Holding Range with 1 mV Signal
THD at Maximum Signal Handling Capacity
of 200 mV lnput
Tape Out Level 75 kHz Dev. 400 Hz 1 mV
NOTE: All sets must meet the requirements of the FCC.
75 psec. de-emphasis for UL and C.S.A. models
and Australian models).
* European models must not be able to tune below
UNIT
kHz
kHz
pV lm
pV lm
uV lm
rrV
dB
o/
/o
kHz
kHz
dB
MHz
MHz
MHz
pV
UNIT NOMINAL LIMIT
4
1t3dB
Frequency response must meet the
(50 psec. de-emphasis for European
87.5 MHz.
NOMINAL LIMIT
515 - 1650 520 -1625
455
500
500
500
22
'10
38
28
35
3.5
200
2AO
200
200
15
30
ot
/o
dB
dB
dB
o/
/o
mV
Hz
4
45
36
45
1.5
250
50 - 2500
5
43
dB
pV
dB
dB
dB
dB
o/
/o
kHz
kHz
kHz
10
t25
t50
37
86.5 - 108.5 88 - 108
*87.5 - 108.5 87.5 - 109
10.7
2.8 5.0
(14.1 dBf) (19.2 dBf)
58 50
36
70 60
45 35
2.5 6
40 25
0.6 1.5
t 500
r b00
t 300 t 300 t 150
o/o 1.5
V1
-3-

FM MPX SECTION
Stereo lndicator "ON" Level
Separation at 1 mV
at 100 Hz
at l kHz
at 10 kHz
Stereo Distortion 1 mV 1 kHz
38 kHz Rejection
S C A Rejection
AUDIO SECTION
lnput lmpedance PHONO Mag.
AUX
Output Power at THD of 0.9 %, 8 ohm
Both Channels Driven at 1 kHz
Power Output, 8 ohms, Both Channels Driven,
THD 0.9 o/o, 30 Hz - 2O kHz
Sensitivity for Rated Power
PHONO Mag.
AUX
Frequency Response at AUX (1W t 2 dB)
BASS Action at 100 Hz
TREBLE Action at 10 kHz
Hum and Noise at Min. VOLUME
Hum and Noise at Max. VOLUME,Tone Max. (AUX mode)
Signal to Noise Ratio
at PHONO Mag. 5 mV lnput (lnput Short)
at AUX 200 mV lnput
Cross Talk at 1 kHz AUX
Bass Compensation at 100 Hz, -30 dB VOLUME
Treble Compensation at 10 kHz, -30 dB VOLUME
TAPE OUT Level PHONO Mag.
at 5 mV lnput
AUX at 200 mV lnput
PHONO Mag. Eq. Response at 100 Hz
at 10 kHz
PHONO Mas. Overload (THD = 0.9 %)
UNIT
pV
dB
dB
dB
o/o
dB
dB
UNIT
K ohm
K ohm
W
W
mV
mV
Hz
dB
dB
mV
mV
NOMINAL
10
NOMINAL
50
450
7.O
b
2.5
150
40 - 22k
t 10
t 10
1
20
LIMIT
20
25
30
22
2.0
40
40
33
38
30
0.8
55
55
60
60
60
+9
+4
dB
dB
dB
dB
dB
LIMIT
5.5
5
3.5
200
50-18k
t 10 r 3
t 10t 3
3
70
50
50
45
+9 t 3
+4t3
250 200
250 200
+13 +13t2
-13 -13t2
82 70
mV
mV
dB
dB
mV
NOTE: The supply voltage is 120 volt AC,60 Hz (for UL and C.S.A. models) from a regulated
power supply. lUse 2201240 volt AC, 50 Hz for European and 240 volt AC, 50 Hz for
Australian models.)
The power source must be isolated f rom other equipment connected to antenna or output.
The room temperature is 25 degrees C.
Nominal Specs represent the design specs; all units should be able to approximate these
- some will exceed and some may drop slightly below these specs. Limit Specs represent
the absolute worst condition which still might be considered acceptable; in nocase should
a unit perform to less than within any Limit Specs.
-4-

2I DISASSEM BLY I NSTR UCTIONS
1) To remove chassis from wood-
en cabinet.
Turn the cabinet upside down
and remove the four Pan head
screws from the bottom cabi-
net.
*-4'4qrCaia** .W ,i
2) Removal of front panel (Alu-
minium panel).
a. Remove the chassis from
wooden cabinet as describ-
ed in 1).
b. Pull out the main chassis.
c. Remove the two Pan head
screws from the top and the
three Pan head screws from
the bottom of the front
panel.
d. Remove knobs and pull off
panel.
3) To remove rear panel from
chassis.
Remove the three Pan head
screws from the rear panel.
3} DIAL STRINGING DIAGRAM
P
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Plates Fully Unmeshed.
o Pointer position: HIGH END
. Start : Spring
o Finish: Hook
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-5-

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-6-

5} ALIGNMENT INSTRUCTIONS
EOUIPMENT REOUIRED
1. AM Signal Generator
2. AC Voltmeter
3.'Oscilloscope
AM IF & RF ALIGNMENT
NOTE:
o Signal Generator output should be no higher
than necessary to obtain an output reading.
r Maintain line voltage at 12O volts. (UL, C.S.A.)
(Use 22Q1240V AC For European & Australian
Models.)
o Set SELECTOR Switch to AM.
o See P.C.B. illustrates for alignment points/ad-
justments.
TUNER COIL & TRIMMER LOCATIONS
AM INTERNAL BAR ANTENNA
FC 1O1) OC 104) OC rO2) fiC 1o5)
FM ANT AM ANT FM RF AM OSC.
TRIMTTER TRIMMER TBIMMER TRIMMER
AM ALIGNMENT SET-UP
AM SIGNAL GENERATOR i
i._-- 2' (6ocm)
FM RF & IF ALIGNMENT
EOUIPMENT REOUIRED
1. FM Signal Generator . ... Output
2. Sweep Generator
3. AC Voltmeter
NOTE:
o Signal Generator output should be no higher
than necessary to obtain an output reading.
o Set SELECTOR Switch to FM.
Figure 3
Level: 1 mV 4. Oscillator
5. Distortion Meter
o Maintain Line voltage at12O volts. (UL, C.S.A.)
(22O/24OV AC For European & Australian
Models.)
o Refer to P.C.B. illustrations for test points/ad-
justments.
lo.
VO LTMETE R
STEP SIGNAL GENERA.
TOR COUPLING SIGNAL GENERA-
TOR FREOUENCY DIAL SET.
TING INDICATOR ADJUSTMENT REMARKS
1
Connect standard
loop ANTENNA to
Signal Generator and
radiate s ignal into
the AM Ferrite an-
tenna. See Fig.3.
455 kHz
(400 Hz, 30% MOD) Point of
non-i nterfer-
ence (near
600 kHz)
AC Voltmeter
to TAPE OUT
Jack
T106
T1 07
T108
T109
Adt'ust for maxi-
mum reading
2Same as above 600 kHz (400 Hz,
30 % MOD) 600 kHz Same as above T105 (OSCCoil)
L6O2 (AM ANT
Coil)
Adjust for maxi-
mum reading
3
Same as above 1400 kHz (400 Hz,
30% MOD) 1400 kHz Same as above TC105
(OSC Trimmer)
TCl04
(ANT Trimmer)
Adjust for maxi-
mum reading
4Repeat Steps 2 and 3 until no further change is noticed.
5
Same as Step 1. 1000 kHz (400 Hz,
30% MOD) Output
level to 100 mV/m
Point of
non-i nterfer-
ence and no
signal
AM Strength
Meter on
Receiver
Select value of
Rr60 Select value so
Meter Pointer on
Receiver reads
between SOYo
and 90 % on the
Meter
-,/
TAPE OUT (L or R)
-7 -

STEP GENERATOR COU.
PLING GENERATOR FRE.
OUENCY RADIO DIAL SETTING INDICATOR ADJUSTMENT REMARKS
1
Sweep Generator to
TP3 on FM Front
end boad
10.7 MHz
(1400 kHz Sweep) Any dial set-
ting where
no notse or
intdrference
exists
Scope to TP7
at R151
(MPX input)
AM/FM/MPX
Board
T101,102,103,
104 (Primary)
FM IFT
Adjust for maximum
amplitude and prop-
er linearity between
1150 kHz markers
Refer to Fig. 5.
2
Sweep Generator to
TP3 thru FM Dum-
my antena
(300 ohm)
10.7 MHz
(1400 kHz Sweep) Any dial set-
ting where
no noise or
i nterference
exists
Scope to TP7
at R151
(MPX input)
AM/FM/MPX
Board
T101,102
FM IFT Adjust for maximum
am,plitude and prop-
er linearity between
1150 kHz markers.
Refer to Fig. 5.
3
Same as above 10.7 MHz
(1400 kHz Sweep) Any dial set-
ting where
no noise or
i nterference
exists
Scope to TP7
at R151
(MPX input)
AM/FM/MPX
Board
T104
FM IFT
(Primary and
Secondary)
Adjust for symmetri-
cal "S" curve as
shown in Fig. 4
4
Signal Generator to
F M Antenna Ter-
minal thru FM Dum-
my antenna
(300 ohm)
98 MHz
(400 Hz, 100%
MOD)
Tune for
Maximum
reading on
meter
Distortion
Meter to TAPE
OUT Jack
T104
FM Discrim.
(Secondary)
Adjust for minimum
distortion
5Same as above *86.s MHz
See Note in Step 7. Tuning gang
fully closed AC Voltmeter and Scope to
TAPE OUT
Jack
Ll 05
(FM OSC) Adjust for maximum
reading on meter
bSame as above 108.5 MHz Tuning gang
fully opened AC Voltmeter
and Scope to
TAPE OUT
Jack
TCl03 (FM
OSC Trimmer) Adjust for maximum
reading on meter
7Repeat Steps 5 and 6 until Tuning Range Covers exactly from 86.5 MHz to 108.5 MHz.
(*European & Australian models must not be able to tune below 87.5 MHz.)
8
Signal Generator to
FM Dummy antenna
(300 ohm)
90 MHz 90 MHz
Tune to
Signal
AC Voltmeter
and Scope to
TAPE OUT
Jack
L1 01
(FM ANT Coil)
1103 (FM RF
Coil; stretch or
squeeze)
Adjust for maximum
reading on meter
oSame as above 106 MHz 106 MHz
Tune to
Signal
AC Voltmeter
and Scope to
TAPE OUT
Jack
TC1O1 (FM
ANT Trimmer)
TCl02 (FM RF
Trimmer)
Adjust for maximum
reading on meter
l0 Repeat Steps 8 and 9 until no further improvement is noticed.
11 Same as Step (8)
ANT. input: 1 mV 98 MHz 98 MHz
Tune to
Signal
10T1 Adjust for maximum
reading on meter
12 Same as Step (8)
ANT. input: 100mV 98 MHz 98 MHz
Tune to
Signal
VR101 Adjust so the Meter
Pointer on Receiver
is full scale.
FM ALIGNMENT SET-UP
3OOO DUMMY FM ANT
(l_ "'' u, tor't
PATTE RN TAPE OUT
(L or R)
Figure 5
FM SIGNAL GENEBATOR
SCOPE PATTEBN
Figure 4
Sweep Gen
-8-
AC V.T-V.M- DISTORTION METER

FM STEREO ALIGNMENT
EOUIPMENT REOUIRED
1. Stereo Modulator.... Connect Stereo Modulator to EXT, Mod. terminal 3. Audio Generator
FM signal generator. 4. AC Voltmeter
Modulation Level of 19kHz Pilot Signal .. . 8-1}o/o b. Oscilloscope
2. FMSignal Generator..OutputLevel .....1mV 6. Distortion Meter
Frequency .. Approximately g8 MHz. 7. Frequency Counter
Deviation .75k{z l0}yo modulation of
composite signal.
NOTE:
o See P.C.B. illustration for alignment/test points.
. Set SELECTOR switch to FM and MODE switch to STEREO.
MULTIPLEX & SEPARATION ALIGNMENT
STEP SIGNAL GENERA.
TOR COUPLING STEREO MODULA. TION IND!CATOR ADJUSTMENT REMARKS
1
Connect to FM An-
tenna Terminal thru
FM Dummy antenna
(300 ohm)
Mono.1 kHz
(1000 Hz, No t\tlod)
lnput 1 mV
Counter connected
to TP14 at Pin No.
12 of lC
VR 103 Ad just for 19 kHz t50
Hz on Counter.
Refer to Fig. 6.
2
Same as above Composite MPX Sig-
nal 1 kHz on Left
Channel ONLY
AC Voltmeter con-
nected for TAPE
OUT Jack of Right
Channel
VR 102
(Separation )Adjust for minimum
reading.
Refer to Fig. 7.
3
Same as above Composite MPX Sig-
nal 1 kHz on Right
Channel ONLY
AC Voltmeter con-
nected for TAPE
OUT Jack of Left
Channel
Same as above Same as above
4Repeat Steps 2 and 3 until AC Voltmeter reading is at least -33 dB re same channel output
(i.e., 33 dB separation).
5
Same as Step 1Composite Signal
1 kHz AC Voltmeter con-
nected to TAPE
OUT Jack
Select value of
R179 With'l 0trrV antenna
input signal, stereo in-
dicator lamp should
come on.
FM STEREO ALIGNMENT SET-UP
FM ANT
TERMINAL
DUMMY
AC VOLTMETER
TAPE OUT
JACK
FREOUENCY
COUNTER
16 15 14 13 12 11 r0
23 4 5 6 7I
Figure 6
-9-
Figure 7

6} LEVEL DIAGRAM
AUDIO FREOUENCY= I kHz
THE VALUE SELECTED PARTS
The value of some parts is selected at the factory for optimum operation. lf the circuitry does not
operate properly, you can change these values.
C101: ln some case, oscillation may take place in FM reception. Removing this capacitor may stop
oscillation.
R128: This is to control level of local oscillator. Use larger value to decrease level.
R160: As noted on page 7, this is to control AM Signal Strength Meter. Use larger value to decrease
Meter deflection.
R179: Use smaller value to increase FM STEREO indicator sensitivity.
m
3
z
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q
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SPEAKER
OUT
35,5dB
2,SmV= OdB
-10-