Realistic STA-7 User manual

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lSerulce
AM /Fwt S
Catalog
STA-7
TEREO RECEIVER
Number:31 -1 968
cusroM MANUFACTURED FoR RADIo sHACK f,[n DMSIoN 0F rANDy conpoRAloN

(1)
(21
(3)
(4)
(5)
(6)
PAGE
ELECTR ICAL PERFORMANCE SPECIFICATIONS 3-4
BLOCKDIAGRAM. -....5
DISASSEMBLY INSTRUCTIONS . ., , .6-7
CIRCUIT OPERATION CHECK . . ..8_16
ALIGNMENT INSTRUCTIONS ,. . .17_20
BUILT.IN PROTECTOR CIRCUIT DESCRIPTION
(MA|N AMP tC HA-1370) . . .20
(7) TROUBLESHOOTING.. .21_23
(8) VALUE SELECTED PARTS ,,,,,..,23
(9) D|AL STRINGTNG D|AGRAM. .....24
(10) LEVEL DTAGRAM ....25
(T1) IC&TRANSISTOR LEAD IDENTIFICATION ,....25
(12) AM/FM RF rF, MPX & PRE, TONE AMP P.C.B. (TOp&BOTTOM VTEWS). .26-27
(13) MA|N AMP & POWER SUPPLY P.C.B. (TOP & BOTTOM V|EWS) .......28
(14) SPEAKER JACKS & SYSTEM/FLAT EOUALIZATION P.C.B.
(TOP & BOTTOM VIEWS) ...,..29
(15) MONTTOR SWTTCH P.C.B. (TOp V|EW) .. ........30
(16) SPEAKER SWITCH P.C.B. (TOP VIEW) . . . . .3O
(17) ELECTRTCAL PARTS L|ST 31-37
(18) EXPLODED VIEW PARTS LIST . ... 38-39
(19) rC TNTERNAL DTAGRAM (LA3350 & HA-1370) ..... .. 40-41
(20) SCHEMATTC DTAGRAM . . 42-43
(21) EXPLODED VIEW 44_45
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-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 (20 dB S/N)
ACA at S/N 6 dB Sensitivity at 1000 kHz
S/N Ratio at 5 mV lnput
AGC Distortion at 1000 kHz,100 mV/m lnput,80 % mod.
AGC Figure-of-Merit
lF Rejection at 600 kHz
lmage Rejection at 1400 kHz
Distortion at 5 mV/m, 30 % mod.
Tape Out Level 5 mV/m lnput, 3A% 4OOHz
Fidelity 5 mV/m lnput, -O dB down (1 kHz = 0 dB)
Whistle Modulation of 2nd and 3rd Harmonic
at 1000 pYlm and 5000 pVlm
Calibration at 600 kHz
at 1000 kHz
FM BAND
Frequency Coverage
IF
IHF Sensitivity at 90,98 and 106 MHz
FM S/N Ratio at 98 MHz, 1 mV lnput
FM Limiting Sensitivity (-3 dB)
lF Rejection Ratio at 90 MHz
lmage Rejection Ratio at 106 MHz
Capture Ratio at 90 MHz, 1 mV lnput
ACA -+. 400 kHz, 100 pV lnput
Audio THD 400 H2,75 kHz dev.
Calibration Accuracy at 90 MHz
at 106 MHz
AFC Holding Range with 1 mV lnput
AM Suppression, AM - 30%, FM - 10O%
Maximum Signal Handling Capacity
Tape Out Level, 75 kHz dev. 1 mV lnput
All sets must meet the requirements of FCC.
Frequency response must meet the 75 psec de-emphasis
(50 psec de-emphasis for Australian models).
FM MPX SECTION
Stereo I ndicator Sensitivity
Separation at 1 mV lnput at 100 Hz
at 1 kHz
at 10 kHz
Stereo Distortion at 1 mV 1 kHz
38 kHz Rejection
SCA Rejection
Stereo Output Level
(UL, C.S.A.)
UNIT
(pV)
(dB)
(dB)
(dB)
%t
(dB)
(dB)
(mV)
UNIT
(kHz)
(kHz)
fuV/m)
(pVlm)
(pVlm)
(pv)
(dB )
(dB)
('/"1
(dB)
(dB)
(dB)
%t
(mV)
(Hz)
%t
(kHz)
(kHz)
UNIT
(MHz)
(MHz)
(pV)
(dBf)
(dB)
(pv)
(dB)
(dB)
(dB )
(dB)
e/,1
(kHz)
(kHz)
(kHz)
(dB )
(mV)
(mV)
NOMINAL
510-1650
455
200
200
200
10
28
40
4
45
.32 45
1.5
210
20-3000
NOMINAL
86.5- 108.5
10.7
2.8
14.2
60
3.2
BO
50
3
45
0.5
r250
3B
200
630
L!MIT
520-1620
500
500
500
20
34
10
38
27
35
3.5
210 L 2.5 dB
50-2500
15
r_25
i.50
LIMIT
88- 1 08
5.0
19.2
55
7.1
70
45
6
30
1.0
r 500
r 500
r.330
30
100
630 r 2.5 dB
LIMIT
20
22
27
2A
2.O
48
560 r 2.5 dB
8
NOMINAL
10
29
34
26
0.6
55
80
560
-3-

NOTE: Set Equalizer Switch to "FLAT" position unless otherwise specified.
AUDIO SECTION
lnput lmpedance PHONO Mag.
AUX
Output Power THD 1 o/o,8{1, Both Channels Driven at 1 kHz
Power Bandwidth, 8 O, Both Channels Driven, under
THD 0.5 %20Hz to 20 kHz (THD 0.7 o/ofor 4 a load)
Sensitivity for Rated Power (10W) PHONO Mag.
AUX
Tape ln
Frequency Response at AUX, Output Power 1 W, 4.2 dB
Bass Action at 100 Hz
Treble Action at 10 kHz
Min. Volume Hum and Noise
Max. Volume Hum and Noise at AUX (Tone Max.)
Signal-to-Noise Ratio PHONO Mag.(lnput shorted)
AUX (lnput terminated with 4.7 KAI
Cross Talk at 1 kHz, AUX position
Bass Compensation at 100 Hz
-30 dB VOLUME Position
Treble Compensation at 10 kHz
-30 dB VOLUME Position
Tape Out Level
PHONO Mag. {2.2mV tnput, 1 kHz)
AUX (160 mV lnput, 1 kHz)
PHONO Mag. Equalizer Response at 100 Hz
at 10 kHz
PHONO Mag. Overload at 1 kHz
Tape Out Level (DlN) (3.3 KO Terminated)
AM 5 mV/m lnput 30 % mod.
FM 1 mV lnput, 22.5k1z dev. 400 Hz
AUX22O mV lnput
Frequency Equalization flesponse in "SYSTEM" position
at 100 Hz, lnput AUX
Music Power at THD 0.9 Yo, 1 kHz (Australian models)
,d
UNIT
(Ko )
(Ksl)
(w)
(w)
(mV)
(mV)
(mV)
(Hz)
(dB)
(dB)
(mV)
(mV)
(dB)
(dB)
(dB)
(dB)
(dB)
(mV)
(mV)
(dB)
(dB)
(mV)
(mV)
(mV)
(mV)
(dB)
(w)
NOMINAL
50
100
14
12
2.2
160
160
15-30 k
*.10
a.10
1
6
60
65
46
+6
LIMIT
12
10
2.2 r.2 dB
160i2dB
160r 2 dB
20-20 k
* 10 +. 2.5 dB
n 10r.2.5 dB
3
15
55
55
40
+6 n 2.5 dB
+4.5 +4.5 +.2.5 dB
150 150a.2 dB
150 150r.2 dB
+13.11 +13.11*.2d8
-13.75 -',13.75 r-2 dB
100 80
3.3 3.3 *.3 dB
3.3 3.3 +. 3 dB
3.3 3.3 a.3 dB
+6.5 +6.5 +. 2.5 dB
18 15
NOTE:The supply voltage is l20voltsAC (for UL & C.S.A.) and24OvoltsAC forAustralian models,
from a regulated power supply.
The power source must be isolated from 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 no case should a unit perform to less than within any Limit spec.
*4-

2. BLOCK DIAGRAM
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3. DISASSEMBLY INSTRUCTIONS
Figure A
1)To remove chassis from MetalCabinet
a) Turn the Cabinet upside down and re-
move the six screws from the Cabinet
bottom. (Figure A)
b) Remove the five screws from the Rear
Panel. (Figure B)
Figure C1
2) Removal of Front Panel
a) Remove the chassis from Metal Cabinet
as described in 1).
b) Pull off the Metal Cabinet.
c) Remove two screws each from the top
and bottom of the Front Panel.
(Figure C1, Czl
d) Remove the two screws from the back of
Front Panel. (Figure D)
e) Remove Knobs and pull off Panel.
Figure B
Flgure C2
-6*
Figure D

3)To remove two bottom covers
i) Removal of Bottom Cover []
Remove the six (A) screws from bottom
cover @ as shown in Figure E.
ii) Removal of Bottom Cover E]
Remove the six (B) screws from bottom
cover @ as shown in Figure E.
IA
(A)
',[,'l'
1'*
B
+(B),l
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(B) ,<--(A)
Figure E
4)To remove Rear Panel from chassis
a) Remove bottom covers as described in 3).
b) Remove the two screws from bottom of
Rear Panel. (Figure F)
c) Remove the four screws frorn the Rear
Panel. (Figure G)
Figure F
Figure G
-7 -

START
CONNECTION
4. CIRCUIT OPERATION CHECK
1)POWER SUPPLY OPERATION CHECK
Connect AC Cord to 120 V AC, 60 Hz (UL, C.S.A.l (24O V AC, 50 Hz for Australian)
Check the Power Supply voltages. (Figure 1)
Check the Power Supply circuits, Fuse and Power Transformer.
DC voltages are not correct.
DC voltages are correct.
Proceed to next section.
2)AUDIO SECTION OPERATION CHECK
(1) MAIN AMP. OPERATION CHECK
Connect 8 O Load to Speaker Output.
Connect DC Voltmeters to Pin No. 3 of MAIN lC 401 (lC4O2) and ground (Plus
Supply) and Pin No. 10 and ground (Minus Supply). See Figure 2.
MAIN AMP EOARD DC VOLTMETER
Figure 2
Check Power Supply Voltage with No lnput (must be r21.2V).
Check D501-504, C505, 506.
Check for short-circuits.
DC Voltage is not i 21.2 V .
DC Voltage is r21.2Y.
9.7V
ltto a 6
CONNECTION
REPAI R
-8-

CONNECTION
NECTION
REPAIR
Connect 8 o Load to Speaker Output.
Check Pop Muting circuit included in MAIN Amp lC 401
about 2-3 seconds after Power is Switched "an,,. (lC4O2l. U nit activates
(1) Check MAIN Amp lC4O1l4O2.
(21 Check TR504.
Pop Muting circuit does not work,
Pop Muting circuit works.
Connect 8 O Load to Speaker Output.
Connect Audio Osc. to AUX input.
Connect V.T.V.M. to Speaker terminals. (Figure 3)
AUDIO OSC.
Check Equalization Response in "SYSTEM" position
position = 0 dB). (Figure 4)
V. T. V. M.
at 100 Hz input. (FLAT
Figure 4t
;e"
+
Check the MAIN Amp Equalization circuit.
See TROUBLESHOOTING.
Equalization Response at 100 Hz does not fall within +6.5 i 2.5 dB.
Equalization Response at 100 Hz falls within +6.5 -+.2.5 dB.
to next section.
Proceed
-9-

CONNECTION
REPAIR
QI PRE.AMP OPERATION CHECK
Set SELECTOR Switch to PHONO.
Connect Audio Osc. to PHONO lnPut.
connect oscilloscope and V'T.V.M' to TAPE oUT Jack' (see Figure 5')
AUDIO OSC. OSCILLOSCOPE
SET
Figure 5
Equalization Curve response (RIAA Curve)
Check for proper PHONO
(See Figure 6).
I+13.r'l
Figure 6
20 -3pHgor.""r,*,
(1) check rR2o1, 2m (rJ;Lf irol.
(21 Check C209,C211,R219,R217 (L ch) and C210,C212,R22O^R218
(R ch).
(3) Check Pre-Amp circuit.
Equalization Response at 100 Hz does not fall within +13.11 r-2 dB and at
'10 kHz does not fall within -13.75 -+.2 dB.
Equalization Response falls within +13.11 L2dB at 100 Hz and -13.75
+.2 dB at 10 kHz.
Proceed to next section.
(3) TONE CONTROL OPERATION CHECK
Same Equipment Connection as Figure 3.
a
36
U
6
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-15
t5
to
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-to
- 10-

Proceed to the next section.
-11 -
Check BASS
(F igure 7) Action at
TONE COiITROL CURVE
. IOOHz + BASS
t tO Nxz .+ TREBLE ,
+lo
a
;o
z
c
u -ro
c
1
Figure 7
-)
AUDTO FiEOUENCY(Hz)
Check Bass Control circuit on TONE CONTROL
Frequency Response does not fall within a.10 r 2.5 dB.
Frequency Response falls within i 10 n 2.5 dB.
Check TREBLE Action at 10 kHz. (Figure 7)
Check Treble Control circuit on TONE CONTROL P.C.B.
Frequency Response does not fall within i 10 r.2.5 dB.
Frequency Response falls within -+.10 +.2.5 dB.
Check LOUDNESS compensation
(Figure 8) with Volume set for -30 dB from rated power.
+6
3
2
Figure 8 $*ou
1.
Check Loudness circuit. 100 lK 10K
-------IAUOOFREOUENCY(HZ) LOUOT\IESSGJRVE
Loudness compensation does not fall within +6 r. 2.5 dB at 100 Hz and
+4.5 -1 2.5 dB at 10 kHz.
Loudness compensation falls within + 6 r 2.5 dB at 100 Hz and +4.5
i.2.5 dB at 10 kHz.
roK
P.C.B.
REPAI R
REPAIR

START
ADJUSTMENT
REPAIR
REPAI
3)AM RF/IF OPERATION CHECK
Adjust AM lFlRF Alignment. (See AM Alignment Section on page 17,)
Set SELECTOR Switch to AM.
Connect Standard Loop Antenna to AM SG and radiate signal into the AM Ferrite
Antenna L7O1.
Connect Oscilloscope, Distortion Meter and V.T.V.M. toTAPE OUT jack on set.
(See Figure 9.)
AM SG
LOOP ANTENNA
Figure 9
Check AM coverage: lowest Dial pointer position should be under 520 kHz and
highest position should be over 1620 kHz.
Readjust AM coverage, (See page 17 for AM Alignment.)
Coverage is less than 520 kHz * 1620 kHz.
Coverage is at least 520 kH.z - 1620 kHz.
Check Antenna Sensitivity for S + N/N 20 dB at 600, 1000and 1400 kHz.
Readjust AM tracking. (See page 17 for AM Alignment.)
AM Sensitivity is worse than 500 pV/m.
AM Sensitivity is better than 500 pYlm. (Nominal Sensitivity is 200pVlm).
L_z'_J AM BAR ANTENNA
Iteo"mt L/ SET
I l// f--
OSCILLOSCOPE V,T.V,M, DISTORTION I/IETER
-12-

REPAIR
R EPAI R
CONNECTION
STEP 5
REPAIR
Check AM Distortion (lnput level to 5 mV/m).
(1) Readjust AM lFlR F Alignment.
(21 Check AM I F/R F circuit.
Distortion is greater than 3.5 %.
Distortion is less than 3.5 Yo.
Check the AM Signal Meter Pointer.
(1) No signal - 0 point t 0.8 m/m
(21 5 mV/m lnput - 75-85 %
(See Figure 10.) No 'TGNAL rNpur
/
0.8mm Figure 10
0.8mm 75-85o/o
Adjust value of R 150.
Signal Meter pointer does not indicate correctly.
Signal Meter pointer indicates correctly.
Same equipmentconnection as Figure gand set lnput level to 5 mV/m.
Check AM TAPE OUT Level.
Check and adjust value of R 162.
TAPE OUT Level does not fall within 21O r 2.5 mV.
TAPE OUT Level falls within 21O *- 2.5 mV.
INPUT:5mV/m
Proceed to next section.
-13-

CONNECTION
REPAIR
STEP 2
CONNECTION
4) FM RF, IF & MPX OPERATION CHECK
Adjust FM Alignment. (See FM Alignment Section on page 18.)
Set SELECTOR Switch to FM.
Connect FM SG (1000 H2,75 kHz dev.) to FM 300 o Antenna Terminal.
Connect Oscilloscope, Distortion meter and V.T.V.M. to TAPE OUT Jack. (See
F igure 1 1.) OSCILLOSCOPE V,I,VM, DISTORTION METER
FM EXI,
ANTENNA TERI\4lNAL ( 3OOo) Figure 11
Check FM coverage: Lowest pointer position should be under BB MHz and high
end should be over 108 MHz.
(1) Readjust FM coverage. (See FM lFlRF Alignment on page 18.)
(2) Check FM RF circuit.
Coverage is not correct.
Coverage is correct.
Check IHF Sensitivity at 90, 98 and 106 MHz.
Readjust FM tracking. (See FM lFlRF Alignment on page18.)
Check the FM RF and lF circuits.
F M lH F Sensitivity is worse than 5 pV.
FM IHF Sensitivity is better than 5 pV. (Nominal Sensitivity is 2.8 pV.)
Same equipment connection as Figure 11.
Set Dial Pointer to 98 MHz (Minimum Distortion point).
FIV] SG @
99 A a9 A aa
oSET
3OOo
DU I\4MY TAF ,our I I
A\JACK Ll
-J
--l \)a/ 'r
-14-

-15-
Check the Signal Meter Pointer.
(1) No signal - 0 point I 0.8 m/m.
(21 1 mV lnput (Mod. - OFF)
Adjust T110 for maximum reading on set's meter.
(3) 100 mV lnput - 90-95% of full scate
Adjust vR 101 so the Meter Pointer on set is g0-9b% of full scale.
(4) Check to be sure that the max. Meter reading point is also the point of mini-
mum distortion. (See Figure 12.)
NO SIGNAL INPUT
90- 95%
Meter Pointer indicates incorrectly.
Meter Pointer indicates correctly.
Same equipment connection as F igure 1 1.
Set FM SG to 98 MHz, 1 mV lnput.
MODE Switch to STEREO.
Check FM TAPE OUT Level.
Adjust value of R 1Bg (L ch) and/or R 190 (R ch).
TAPE OUT Level is not 630 mV t 2.5 dB.
TAPE OUT Level is 630 mV t 2.5 dB.
Check TH. Distortion for Mono. signal.
Readjust RF/lF Alignment on page 18.
TH. Distortion is greater than 1.0%.
INPUT:lOOmV/m
REPAIR
CONNECTION
REPAI R
STEP 6
REPAIR
Readjust T110 and VR 101.

TH. Distortion is less than 1.0%.
Proceed to next section.
(3) FM MPX OPERATION CHECK
Adjust for FM MPX Alignment on page 19.
Same equipment connection as Figure 11.
Connect FM Stereo SG to FM SG. (Figure 13)
Stereo Modulation
MAIN & SUB - 90% (67.5 kHz dev.)
Pilot 8% ( 6 kHz dev.)
Frequency 98 MHz, 1 kHz mod.
lnput 1 mV FM STEREO SG FM SG
3OOo DUMMY TAPE OUT JACK
Figure 13 OSCILLOSCOPE V.T.V.M. DISTORTION METER
FM EXT.
ANTENNA TERIVI|NAL (3ooo)
Check Stereo Separation at 100,
i k and 10 kHz.
Check the Stereo lndicator Sensitivity.
{input: near 10pV)
Readjust FM MPX Alignment on page 19.
Check the FM MPX circuits.
Stereo Separation is worse than 22 dB at 100, 27 dB at
10 kHz.
Stereo Separation is better than22 dB at 100, 27 dB at
10 kHz.
lkand20dBat
1 kand20dB at
Adjust value of R 167.
Check FM MPX circuits.
Stereo Beacon Sens. is worse than 20 pV.
Stereo Beacon Sens. is better than 20pV. (Nominal sensitivity: 10pV)
CONNECTION
STEP 1
REPAIR
Proceed to Alignment section.-16-

5. ALIGNMENT INSTRUCTIONS
EOUIPMENT REOUIRED
1. AM Signal Generator
2. AC Voltmeter
3. Oscilloscope
TUNER
(TCrOr)
FM ANT.
TRIMMER
corl &
(TC rO4)
AM ANT.
TRIMMER
TRIMMER LOCATIONS
(TCrO2) (Tct05)
FM RF AM OSC.
aM osc corL
fito5)
f-
,@
FM ANT.
( Lrot) M
Y
OSC TRIMMER
(TCr03)
AM IF & RF ALIGMENT
NOTE: . Signal generator output should be no higher than necessary
. Maintain line voltage a,t 12O volts. (UL, C.S.A.) (Use 240 V
o Set SELECTOR Switch to AM.
o See P.C.B. illustrations for alignment points/adjustments.
AM ALIGNMENT SET-UP
Figure
-17-
FM RF COIL
( Ll03 )FM OSC CO|L
(Lro5)
to obtain an output reading.
for Australian models.)
STEP SIGNAL GENERATOR
COUPLING SIGNAL GENERATOR
FREOUENCY DIAL SETTING INDICATOR ADJUSTMENT REMARKS
1
Connect standard loop
ANTENNA to Signal
Generator and radiate
signal into the AM
Ferrite antenna.
See Fig. 14.
455 kHz
(4OOHz,30% MOD) Point of non-
interference
(near 600 kHz)
AC Volt-
meter to
TAPE OUT
JACK
T106
T 107
T108
T109
Adjust for
maximum
reading.
2Same as above 600 kHz (400 Hz,
30% MOD) 600 kHz Same as
above T105 (OSC Coil)
L7O1 (AM ANT
Coil)
Adjust for
maximum
reading.
3
Same as above 1400 kHz @OAHz,
30% MOD) 1400 kHz Same as
above TC105
(OSC Trimmer)
TC't04
(ANT Trimmer)
Adjust for
maximum
reading.
4Repeat STEP 1 and then STEPs 2 and 3 until no further change is noticed.
5
Same as step 11000 kHz (4OOHz,
30% MOD)
Output level to
5 mV/m
Point of non-
interference
and no signal
AM Strength
Meter Select value of
R 150 Meter pointer
on Receiver
should indicate
between 75%
and 85% on
the Meter.
AM SIGNAL GENERATOR
VOLTMETE R
,,\
14

FM RF & !F ALIGNMENT
EOUIPMENT REOUIRED
1. FM Signal Generator . . . Output Level: 1 mV 3. AC Voltmeter
2. Sweep Generator 4. Oscilloscope
5. D istortion Meter
NOTE: o Signal Generator output should be no higher than necessary to obtain an output reading.
o SeTSELECTOR Switch to FM.
. Maintain line voltage at 120 volts. (UL, C.S.A.) (240V for Australian models.)
o Refer to P.C.B. illustrations for test points/adjustments.
STEP GENERATOR
COUPLING 3ENERATOR FREOUENCY RADIO DIAL
SETTING INDICATOR ADJUSTMENT REMARKS
1
Sweep Generator to
"FM ANT" terminal
on FM Front end
board
10.7 MHz
(1400 kHz
Sweep)
Any dial setting
where no noise
or interference
ex ists
Scope to TP1 at
R144 (MPX in-
put)
AM/FM/MPX
Board
T101, 102, 103
T104 (Primary)
FM IFT
Adjust for maximum
amplitude and prop-
er linearity between
L150 kHz markers.
Refer to Fig. 15.
2
Sweep Generator to
FM Antenna Termi-
nal thru FM Dummy
antenna (300 ohm)
T101,102
FM IFT
3Same as above T104 FM IFT.
(Primary and
Secondary)
Adjust for symmetri-
cal "S" curve as
shown in Fig. 'l 5.
4
Signal Generator to
FM Antenna Termi-
nal thru FM Dumml
antenna (300 ohm)
98 MHz
(4OO Hz, 10Oo/o
MOD}
Tune for Maxi-
mum reading
on meter.
Distortion Meter
to TAPE OUT
Jack
T104
FM Discrim.
(Secondary)
Adjust for minimum
distortion.
5
Same as above 86.5 MHz Tuning gang
fully closed AC Voltmeter
and Scope to
TAPE OUT
Jack
L1 05
(FM OSC) Adjust for maximum
reading on meter.
bSame as above 108.5 MHz Tuning gang
fully opened TC103 (FM
OSC Trimmer)
7Repeat STEPs (5) and (6) until Tuning Range Covers exactly from 86.5 MHz to ,l08.5 MHz.
I
Signal Generator to
FM Dummy
antenna (300 ohm)
90 MHz 90 MHz
Tune to Signal AC Voltmeter
and Scope to
TAPE OUT
Jack
L101
(FM ANTCoil)
L103(FM RF
Coil; stretch or
squeeze)
Adjust for maximum
reading on AC Volt-
meter.
ISame as above 106 MHz 106 MHz
Tune to Signal TC101 (FM
ANT Trimmer)
TCl02 (FM
RF Trimmer)
10 Repeat STEPs (8) and (9) until no further improvement is noticed.
1"1
Same as STEP (8)
ANT. input: 1 mV 98 MHz 98 MHz
Tune to Signal T110 Adjust for maximum
reading on the
Receiver's meter,
12
Same as STEP (8)
ANT. input: 100m\ VR 101 Adjust so the Meter
Pointer on Receiver
is 90-95% of full
scale.
-18-

FM ALIGNMENT SET-UP
3OOO DUMMY FM ANT
Sweep Gen.
Figure 15
FM STEREO ALIGNMENT
Equipment Required
1. Stereo Modulator
2. FM Signal Generator . .
3. AC Voltmeter
4. Oscilloscope
5. D istortion Meter
6. Frequency Counter
Note: See P.C.B. illustration for alignment/test points.
Preliminaries
Set SELECTOR switch to FM STEREO.
TAPE OUT
{L or R)
AC V.T.V.M. DISTORTION METER
generator.
{i rP1
l..i_- atR144 @7 Al
Figure 16
Connect Stereo Modulator to EXT. Mod. terminal on FM signal
Modulation Level of 19 kHz Pilot Signal .....8-10%
Output Level ..... 1 mV
Frequency ......... Approximately 98 MHz
Deviation 75 kHz 1OO7o modulation of composite signal
FM SIGNAL GENEBATOR
SCOPE PATTERN
MULTIPLEX & SEPARATION ALIGNMENT
STEP SIGNAL GENERATOR
COUPLING STEREO MODULATION IND ICATOR ADJUSTMENT REMARKS
1
Connect to FM Antenna
terminal thru FMdummy
antenna (300 O).
Mono. 1 kHz
(1000 Hz, No Mod)
lnput 1 mV
Counter connected
toTP2 at Pin 12 o{
IC
VR 103 Adjust for 19 kHz
.t50 Hz on Counter.
Refer to Fig. 17.
2
Same as above Composite MPX Signal
1 kHz on Left channel
ONLY
AC Voltmeter con-
nected for TAPE
OUT jack of R ight
channel
VR 102
(Separation )
Adjust for minimum
read ing.
Refer to Fig. 18.
3
Same as above Composite MPX Signal
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 -30 dB re same channel out (i.e. 30 dB
separation ).
5
Same as step 1Composite Signal
1 kHz AC Voltmeter con- nected to TAPE
OUT jack
Select value
of R167. With 10 pV antenna
input signal, stereo
indicator lamp
should come on.
r
- 19-

TP2
161514131211109
rc 101 LA 3350
| 23 4 5 6 7I
FM STEREO ALIGNMENT SET-UP
Figure 17
STEREO MOOULAYOR
orsroRTroN
METER
TERMINAL
TAPE OUT
JACK
Figure 18
6. BUILT.IN PROTECTOR CIRCUITS DESCRIPTION
1)Current Limiter
lf speaker terminals are shorted, the output line is grounded and excessively high current flows
through the Output stage in the lC, This high current is sensed by the Current Limiter circuit in the
lC and decreases the output current (because of output current limiting). lf this should occur, turn
off Receiver. When problem is corrected, turn the Receiver on again.
2) Thermal shut-down circuit
lf the chip temperature reaches approximately 150"C, the output power and current drain are
automatically reduced to protect the device.
3)Muting circuit
Shock or "pop" noise occurring during power "on" is reduced by a built-in muting system.
NOTE: +Bz is a regulated power supply, whose rise time constant is maintained at approx. 2 seconds
to achieve muting for this clip.
(MAIN AMP lC HA-1350)
+82 +Bt
!
I
II
-20-