Harman Kardon TU915 User manual

The
Harman
Kardon
|
a
_
Model
TU915
wnat
arta
[oo
’
DIGITAL
SYNTHESIZED
QUARTZ-LOCKED
TUNER
echnical Manual
k
harman/kardon
y
240 CROSSWAYS PARK WEST, WOODBURY, N.Y. 11797 bo
1112-H15277A1 P-08848 1850 PRINTED IN JAPAN

7 Ww
7
o
=)
[
SPECIFICATIONS
FM SECTION
Tuning Range
50dB Quieting Sensitivity
Nominal Limit
87.5 ~ 108.0MHz
@ AM SECTION
Tuning Range
Usable Sensitivity
Nominal Limit
520 ~ 1,710kHz
Mono
15.2dBf
<
18dBf
External
Antenna
10uV
<
20uV
Stereo
36.2dBf
<
40dBf
Loop
Antenna
220uV/m
C
Usable
Sensitivity
10.6dBf
(IHF)
<
15dBf
Selectivity
54dB
>
35dB
Image
Ratio
98dB
>
80dB
Signal
to
Noise
Ratio
54dB
=
50dB
1F
Rejection
105dB
=>
85dB
Image
Rejection
48dB
>
38dB
Spurious
Response
Rejection
120dB
> 95dB
IF
Rejection
69dB
=
50dB
Capture Ratio 1.0dB < 2.0dB e H 4/99. “4A. "
Alternate Channel Selectivity 70dB = 50dB DIMENSIONS(WxHxD} ave xe apo nal 1/16
AM Rejection 64dB > 45dB
Signal
to
Noise
Ratio
e@WEIGHT
8
Ibs.
6
oz.
(3.8
kg)
for U.S.A. & Canada models @POWER SUPPLIES
Mono 83dB 2 78dB for U.S.A. & Canada models AC120V, 60Hz
Stereo 75dB 2 70dB for General model AC100/120/220/240V,
for General model > 50/60Hz
M 77dB 2 72dB
Stereo 6odB > 64d8 @POWER CONSUMPTION —-16W
Total Harmonic Distortion
Mono 0.05% S 0.15%
Stereo 0.06% < 0.3% This specification is the target of servicing. But, there is a case
that the specification is not applicable to the measurement
Stereo Separation at 1kHz condition and instrument.
for U.S.A. & Canada models
for General model
Output Level/tmpedance (Stereo)
for U.S.A. & Canada models
for General mode!
65dB = 45dB
55dB = 40dB
Specifications and components subject to change without notice. C
Overall performance will be maintained or improved.
780m V/2.2kQ2
420mV/2.2kQ
LEAKAGE TEST (FOR SERVICE ENGINEERS IN THE U.S.A.)
Before returning the unit to the user, perform the following safety checks:
1. Inspect all lead dress to make cer- (
tain that leads are not pinched or
that hardware is not lodged be-
tween the chassis and other metal
parts in the unit.
2. Be sure that any protective devices
such as nonmetallic control knobs,
insulating fishpapers, cabinet backs,
adjustment and compartment cov-
ers or shields, isolation §resistor- .
capacity networks, mechanical in- €.
sulators, etc. which were removed
for servicing are properly reinstalled.
3. Be sure that no shock hazard exists; check for leakage
current using Simpson Model 229 Leakage Tester,
standard equipment item No. 21641, RCA Model
WT540A or use alternate method as follows:
Plug the power cord directly into a 120-volt AC
receptacle (do not use an Isolation Transformer for
this test). Using two clip leads, connect a 1500
Ohm, 10-watt resistor paralleled by a 0.15uF capac-
itor, in series with all exposed metal cabinet parts
and a known earth ground, such as a water pipe or
conduit. Use a VTVM or VOM with 1000 Ohms per
volt, or higher, sensitivity to measure the AC voltage
drop across the resistor. (See Diagram.) Move the
resistor connection to each exposed metal part having
a return path to the chassis (antenna, metal, cabinet,
screw heads, knobs and control shafts, escutcheon,
etc.} and measure the AC voltage drop across the
resistor. (This test should be performed with the
power switch in both the On and Off positions.)
A reading of 0.35 volt RMS or more is excessive and indicates a potential shock hazard which must be corrected before
returning the unit to the owner.
SIMPSON MODEL 229 ETC. FOR
LEAKAGE TEST
TO EACH EXPOSED
METAL SURFACE OF
UNIT UNDER TEST
TO AC GROUND SUCH
AS WATER OR BX CABLE,
GROUND CONDUIT, ETC.
LEAD
HIGH
VOLTAGE
OR +LEAD
OAC SCALE O
TEST PROBE
TO EXPOSED
METAL PARTS
CONNECT TO KNOWN
EARTH GROUND

DISASSEMBLY PROCEDURES (REFER TO PAGES 8 AND 16)
1] CABINET TOP (131) REMOVAL 6. Unsolder the Holding Brackets (175) from shield case
Remove 6 screws @ and remove the Cabinet Top (131). of FM front end on the Main P.C. Board (PCB-1).
; 7. Remove 10 screws @ and hexagon nut @ and
i 2| CABINET BOTTOM ASSEMBLY (102) REMOVAL remove the Main P.C. Board (PCB-1).
: Remove 4 screws © and remove the Cabinet Bottom
Assembly (102). 5} STATION DISPLAY P.C. BOARD (PCB-2)
REMOVAL
3) FRONT PANEL ASSEMBLY (101) REMOVAL 1. Remove the Front Panel Assembly (101). (Refer to
1. Remove the Cabinet Top (131). (Refer to step [1] .) step [3} .}
2. Remove 7 screws @ and remove the Front Panel 2. Remove 4 screws @ and remove the Station Display
Assembly (101). P.C. Board (PCB-2) with the Tuning & High Blend
Switches P.C. Board (PCB-7), LED Display Assembly
4] MAIN P.C. BOARD (PCB-1}) REMOVAL (D901), Window (142) and Bracket (180).
1.
Remove
the
Cabinet
Top
(131).
(Refer
to
step
[4]
.)
3.
Remove
2
screws
@
and
remove
the
Bracket
(180)
2. Loosen 2 screws ®@ and pull out the Shaft (198) with the LED Display Assembly (D901) and Window
with the Knob Assembly (103). (142) from the Station Display P.C. Board (PCB-2).
3. Open the lid of connectors (J10, J11, J151, J351, 4. Remove the solder of the connector (J355) between
J701, J801) on the Main P.C. Board (PCB-1) and then Tuning & High Blend Switches P.C. Board (PCB-7)
disconnect the lead wires. and Station Display P.C. Board (PCB-2) and break the
for 4. Disconnect the connector (J12) from the connector connection.
(P12) on the Main P.C. Board (PCB-1).
5. Open the lid of connector (J1) on the Power Switch
P.C. Board (PCB-4) and then disconnect the lead
wires.
POWER
CORD
REPLACEMENT
(FOR
SERVICE
ENGINEERS
OTHER
THAN
NORTH
AMERICA)
(
In
order
to
prevent
fire
or
shock
hazard
when
replacing
the
power
cord,
follow
the
procedure
below
to
replace
the
parts
with
the standard
supply. parts.
cot
CONNECTOR
SN BLUE LEAD
1 ;
CS > RED LEAD
renee <J HOLDER
TRANSFORMER .
RY PI
POWER CORD
open TY Aa tn Tg een
reat pe marc ci

ALIGNMENT PROCEDURES
MB STANDARD FREQUENCY CHECK
Condition: @Set the Function selector to the ‘‘fm” position.
e Connect the Frequency counter to TP2 (+)
and TP5 (—).
Mi AM ALIGNMENT
Conditions: @Set the Function selector to the “am” position.
®@ Depress the Muting switch to the “off” position.
(REFER TO PAGES 15 AND 16)
98.3MHz
Standard
modulation
of
the
AM
Signal
Generator
is
400Hz
at
30%.
109MHz + 2kHz
e Connect the DC Volt Meter to
TP1 (+) and TPS (—).
Tracking
Tuned
Indicator
iFM ALIGNMENT
1710kHz
TC252
23V +0.5V
e Connect the AM Test Loop
Antenna cable into the output
jack of AM Signal Generator.
Place AM Test Loop Antenna
close enough to couple signal
into the AM Loop Antenna
(Li),
Make the signal as weak as
possible.
Connect the VTVM and
Oscilloscope to the Fixed
Output jacks.
1400kHz
—
1400kHz
T251
T252
Maximum output level
and symmetrical curve
on scope.
1400kHz 1400kHz
TC251
Maximum output
[ 600kHz | 600kHz L251 |
Repeat steps 3 and 4 for optimum sensitivity.
1000kHz
1000kHz
Confirm the Tuned
indicator lights at 60dB
input.
Conditions:
@
After
the
Power
switch
is
pushed
on,
wait
for
5
minutes
before
adjusting
so
that
the
most
stable
operation
is
obtained.
@Set
the
Function
selector
to
the
“stereo
fm”
position.
© Depress the Muting switch to the “off” position.
®Depress the High Blend switch (button in).
1kHz, 100% modulation
1kHz, 53% modulation
L+R=45.5%, L—R=45.5%, 19kHz=9%
L+R=22.5%, L—R=22.5%, 19kHz=8%
Discrimi-
nator
Tuned
Indicator
Signal
Indicator
e Connect the FM Signal
Generator to FM 300Q
BAL Antenna terminals
through the 300Q balanced
dummy.
e Connect the Oscilloscope and
Distortion meter to the Fixed
Output jacks.
Connect the DC Volt Meter
to TP3 (+) and TP5 (—).
98.1MHz
T201 (A)
Adjust so that the
Tuned indicator lights
when the output fre-
quency of the FM
Signal Generator is
shifted to Low Frequ-
ency side and High
Frequency side by the
same but limited
amount both from
98.1MHz (imV).
98.1 MHz
98.1MHz
T201 (B}
Minimum distortion
Repeat steps 1 and 2 for optim
um sensitivity.
VR202
Tuned indicator lights
at 7yV input.
98.1MHz
Adjust so that the DC
voltage becomes 9V at
ImV input. At this
time, Confirm the five
signal indicator lights.
oom,
ian
eevee tens mare pr pone ney sgn
“ms Fh Pig
LON IT IEE RO SRG NOE ERR ABO Sp,

MPX
Free Run
Stereo
Threshold
e Connect the Stereo Modulator
to FM Signal Generator.
Connect FM Signal Genera-
tor to FM 3002 BAL Antenna
terminals through the 30082
balanced dummy.
e Connect the Frequency
Counter to TP4 (+) and TP5
(—).
e Connect the VTVM and Oscil-
loscope to the Fixed Output
jacks.
98.1MHz
(unmodula-
tion)
98.1MHz
19.00kHz + 0.02 kHz
98.1MHz
98.1MHz
Stereo FM indicator
lights at 30uV + 2dB
input.
SCA
Rejection
e Connect the Stereo Modulator
to FM Signal Generator.
Connect FM Signal Generator
to FM 30022 BAL Antenna
terminals through the 3002
balanced dummy. Apply
67kHz, 10% FM modulation
SCA signal to the SCA input
jack of Stereo Modulator.
e Connect the VTVM and
Oscilloscope to the Fixed
Output jacks through 19kHz
Low Pass Filter.
98.1MHz
Minimum output
Sub-carrir
Rejection
Separation
Separation
Balance
e Connect the Stereo Modulator
to FM Signal Generator.
Connect FM Signa! Generator
to FM 3002 BAL Antenna
terminals through the 300Q
balanced dummy.
e Connect the VTVM and
Oscilloscope to the Fixed
Output jacks.
98. 1MHz
98.1MHz
Minimum output at
19kHz pilot signal
only by Stereo Modu-
lator.
VR152
LPFi51
98.1MHz
98.1MHz
Adjust so that the
right channel output
becomes minimum
when only the left
channel of the Stereo
Modulator is modulat-
ed,
Adjust so that the left
channel output
becomes minimum
when only the right
channel of the Stereo
Modulator is modulat-
ed.
98.1MHz
|
With the VR192,
correct unbalance
between minimum
outputs the right and
left channels.
|
Repeat steps 10 and 11 for optimum sensitivity.
ete esc TT an Ta ee ee

CIRCUIT DESCRIPTION
(1) SIGNAL PATH
The FM signal is amplified in the RF amplifier 3SK74
(3SK85, 3SK101) at the front end, then mixed with the
output of the local oscillator 2SC461 (2SC930,
25C2834) and converted into a signal of the 10.7MHz
intermidlate frequency. This 10.7MHz signal is amplified
in the IF amplifier consisting of the ceramic filters
CF201 ~ CF203 and 0201 ~ 0204 and fed to @ pin of
1C201. In 1C201, the signal is amplified in the triple IF
amplifiers, and after being detedted in the quadrature, it
is put out from ©) pin as an audio signal, which is then
sampled and holded by means of the 38kHz- signal
produced in C151 and fed to the audio amplifier.
(2) MUTING OPERATION WHILE TUNING
When not of tune or the signal is too weak, the muting
control voltage is taken out from @ pin of !C201 and is
fed to the base of 0205, whose collector then becomes
low level. The muting signal is sent to the muting control
circuit. As 0357 becomes high level, the signal is fed to
NAND 1C351. The@)pin of 1C351 and Q7 become low
level and high level respectively and muting gates 0317
(Lech) and 0318 (Rch) become low level, thus muting
operation is completed.
(3) SIGNAL INDICATOR CIRCUIT
1) FM tuner section
The signal indicator drive signal taken out from @®) pin
of 1C201 passes through VR201, amplified in 0351 ~
Q353 amplifiers and fed to D901.
2) AM tuner section
The signal indicator drive signal taken out from pin
of 1C251 is fed to the base of Q351, amplified in 0351
~ 0353 amplifiers and fed to D901.
(4) SYNTHESIZER SECTION
1) FM
The output of local oscillator in the front-end is fed to
@® pin of the pre-scaler 1C701, then divided by 30 or
32 and fed to @ pin of the PLL synthesizer IC702.
The standard quartz oscillator output (7.2MHz) is divid-
ed by 288 in 1C702 and 25kHz standard signal is obtain-
ed. The divided local oscillator output is compared with
the 25kHz standard signal in the phase comparator.
When the divided: local oscillator frequency is higher
than standard frequency, @ pin of 1C702 becomes high
level but when it is lower, pin of |1C702 becomes low
level. When the both frequencies are equal, pin be-
comes floating.
@) pin output of 1C702 is fed to the vari-cap diode of
the front-end through L.P.F. (0701, 0702, Q703) and
controls the frequency of VCO (local oscillator fre-
quency.)
2) AM
(When SW712 frequency step control switch is set to
10 kHz position.)
The local oscillator output of AM 1C251 is fed to pin
of the PLL synthesizer 1C702 and divided. The standard
quartz oscillator output (7.2MHz) is divided by 720 in
1€702 and 10kHz standard signal is obtained. The
divided local oscillator output is compared with the
10kHz standard signal in the phase comparator.
(5) PRESET MEMORY
1) Memory
While the memory button is pressed ON (the memory
indicator is lit), pressing one of the preset keys of M1~
M8 (SW701 ~ SW708) causes the pin corresponding to
the pressed key among 42 ~ pins of 1C702 becomes
high level. The frequency displayed then is memorized.
2) Call
The
memory
content
(frequency)
is
called
out
by
pressing
one
of
the
preset
keys
of
M1
~
M8
(SW701
~
SW708).
(6) FM/AM SCANNING
1)
With
the
tuning
mode
switch
(SW201)
set
to
AUTO,
tuning
the
tuning
control
clockwise
causes
the
photo
switch
0801
or
O802
to
turn
OFF
and
the
frequency
increases,
while
turning
the
tuning
control
counter-
clockwise
causes
the
photo
switch
Q801
or
Q802
to
turn
OFF
and
the
frequency
decreases.
Scanning
stops
when
63
pin
(stop
terminal)
of
|C702
becomes
high
level.
2)
With
the
tuning
mode
switch
(SW201)
set
to
MANUAL,
turning
the
tuning
control
clockwise
or
counterclockwise
causes
the
frequency
to
increase
or,
decrease by one step (channel space).
C
ge aro Sea PE SN

Re
OC
a
Sf
Tans
wt
bo
at
reg
EE
y3aAINa
AV1dSIG
K
|
AV1dSI0
NOILWLS
£0031
Y3IZISHLNAS
11d
z0291
"
NY ye
TOYLNOD
aLnWw
NOILVOIGNI
Oqd3als
LINDHIS
T39NV9
VOS
‘4
ra
JIaVIUVA
O—Ws’
'
alv)
aaxia
©
ANdLNO
4H
Ea
<_|
i \
‘dV Olany
TaAa1
(9)
e)—6)
(202)
1gz0
indino
LINDwIO
|
NOLLVYAN3SD
B
XdW
Td
Wa
NOILO3S
AY
|
i
aS1Nd
ONIN
VS
SLO!
C1)
LSzot
(€)
be
-—O
Z
INV
WY
a
31avINVA
O—Wwas’
aaxta
O
Nia
<—
|
INdLNO 44
EA
‘dW O1any y3dsng
XdW
O10H
@
J1dNVS
in
UV1VOS
aud
LOzol
(s)<-O
4130
3YuNLVYOVND
dW
JI
INS
LOZOl
NOILVSIGNI
HLONAYLS
TVNOIS
Lo6a
“LNV
Wa
dv dl dy si
YaXIW dwy
ty
BLOCK DIAGRAM

GENERAL UNIT EXPLODED VIEW
eral model Military version
Gen

GENERAL UNIT PARTS LIST
Ref. No. | Part No. l Description
101
A443-TU915A
Front
Panel
Assembly
102
A424-TU915A
Cabinet
Bottom
Assembly
103
A630-TU915A
Knob
Assembly,
Function
104
A630-TU915B
Knob
Assembly,
Tuning
105
A662-TU915A
Push
Button
Assembly,
Muting,
Tuning,
High
Blend.
106
B211-TU915A
Chassis
Assembly
131
1414-02201
Cabinet
Top
133
1424-12702
Cabinet
Back
(for
U.S.A.
&
Canada
models)
"
1424-13002
Cabinet
Back
(for
General
model)
"
1424-12703
Cabinet
Back
(for
General
model
Military
version)
137
1319-0139
Foot
142 1531-07101 Window
153
1634-04901
Knob,
Muting
Level
156
1660-00401
Push
Button,
Power
157
1662-16501
Push
Button,
Preset,
Memory
170 2112-11773 Sponge
171 2114-415027 Bushing
172 2132-01401 Spacer
175 2218-7001 Holding Bracket
178
2219-7981
Bracket
(for
U.S.A.
&
Canada
models)
”
2219-8000
Bracket
(for
General
model)
179 2219-7999 Bracket
180 2219-8001 Bracket
181 2219-8021 Bracket
182 2219-7984 Bracket
183 2219-8002 Bracket
184 2219-7964 Bracket
187
2222-7169
Heat
Sink
194 2240-7120 Holder
198 2601-7130 Shaft
199 2601-7069 Shaft
201
2602-007120
Tuning
Shaft
203
2133-7026
Protector
208 2672-7018 Lever
214
2651-210189
Spring
223
2447-10227
Hexagon
Nut
225
2459-3003511
Rivet
226 2111-11160 Felt
250
2240-7218
Holder,
Antenna
251
2132-7116
Spacer
(General
model
only}
301
2347-400647
Self-Tapping
Screw
(+)
(4
x
6
mm)
302
2347-300647
Self-Tapping
Screw
(+)
(3
x
6
mm)
303
2347-300627
Self-Tapping
Screw
(+)
(3
x
6
mm)
304
2322-300629
Screw
(+)
(3
x
6
mm)
305
2347-301041
Self-Tapping
Screw
(+)
(3
x
10
mm)
306
2347-301427
Self-Tapping
Screw
(+)
(3
x
14
mm)
1111-J30169
1111-J30170
1222-7224
1221-787147
4474-29
Owner
Guide
(for
U.S.A.
model
&
General
model
Military
version)
Owner Guide (for Canada & Genera! models)
Packing Cushion
Packing Box
AC
Adaptor
(for
General
model
Military
version)
PS eR VRP OT PPE RIO GEN Ea gg ery

10
ELECTRICAL PARTS LIST
Ref. No.
Part No,
Description
AP1
An
AT1
ar
A SW2
4$01
ACO1
ARI
D901
L1
LUG1
AR2,3
AR10, 13, 17, 151, 220
4 R171, 172, 301, 302
R158
A R703
R787, 788
VR151
VR152
VR191, 301
VR192
VR201, 351
VR202
VR303/304
C5,6
C7, 8, 15, 171, 172, 206,
301, 302
C9, 10
C11
C12
C13, 709
C14, 17
C16, 18, 352
C19, 20, 152, 155, 257
C101, 151, 262
C102, 158, 718, 719, 806,
807
C153
C154
C156
C157
C160, 161, 187, 209
C162, 175, 176
C163
C173, 179
C174
C177
C178
C180, 181, 185
C182, 183, 184, 186, 311,
312
4161-71147
4161-7256
5584-701477
5584-701478
4411-104736
4474-164
4443-712
5135-335J50P
5623-LT1137
5911-244
4211-5005
1397-6
4161-71184
RESISTORS
5102-2R2579
5102-2204715
5102-1004715
5174-163381
5102-1014715
5171-121581
CONTROLS
5101-4727173
5101-10371920
5101-50271920
5101-50171920
5101-50371920
5101-20371920
5113-50271151
CAPACITORS
5345-228D0962
5345-477C041
5345-108C041
5345-476F041
5345-107F041
5345-107E041
5345-476D041
5345-226C041
5345-106C041
5345-227C041
5345-225F0952
5359-4725851
5359-6815851
5345-105F0952
5345-475D0952
5359-1015851
5359-4715851
5359-1225851
5359-2215851
5359-1515851
5359-8215851
5359-1215851
5345-226C0951
5359-1025851
Power Cord (for U.S.A. & Canada models)
Power Cord (for General model)
Power Transformer (for U.S.A. & Canada models)
Power Transformer (for General model)
Rotary Switch, Voltage Selector (General model only)
AC Socket, Unswitched (U.S.A. & Canada models &
General model Military version only}
Connector, Power Cord (General model only)
Resistor, 3.3MQ, 1/2W, Carbon (U.S.A. & Canada
models only)
LED Display Assembly
_AM Loop Antenna
Lug Terminal (U.S.A. & Canada models only)
Dipole Antenna (Accessory)
Connection Wire (Accessory)
2.29, +5%, 1/4W, Fuse
220, +2%, 1/4W, Fuse
1022, +2%, 1/4W, Fuse
16k, 1%, 1/4W, Metal
10022, +2%, 1/4W, Fuse
120Q, £5%, 1W, Metal
4.7kQB
10kQB
5kQB
5002B
50kQ2B
20k2.B
5kQB, Output Level
2200uF, +20%, 25V, Electrolytic
470uF, +20%, 16V, Electrolytic
1000uF, +20%, 16V, Electrolytic
47 uF, +20%, 50V, Electrolytic
100uF, +20%, 50V, Electrolytic
100uF, +20%, 35V, Electrolytic
47uF, 20%, 25V, Electrolytic
22uF, +20%, 16V, Electrolytic
10uF, 20%, 16V, Electrolytic
220uF, +20%, 16V, Electrolytic
2.2uF, +20%, 50V, Electrolytic
4700pF, +5%, 100V, Polypropylene
680pF, 5%, 100V, Polypropylene
1pF, 20%, 50V, Electrolytic
4.7 pF, +20%, 25V, Electrolytic
100pF, +5%, 100V, Polypropylene
470pF, +5%, 100V, Polypropylene
1200pF, +5%, 100V, Polypropylene
220pF, +5%, 100V, Polypropylene
150pF, 5%, 100V, Polypropylene
820pF, +5%, 100V, Polypropylene
120pF, +5%, 100V, Polypropylene
22uF,+20%, 16V, Electrolytic
1000pF, +5%, 100V, Polypropylene
roa