Technics Quartz ST-G7 User manual

ORDER NO. HAD84062801C9
Service
Manual
Tuner
CYUARTZ
Synthesizer
ST-G
A
FM/AM
Stereo
Tuner
eaten
| (K) ...Black Type
(S)...Silver Type
SPECIFICATIONS
(DIN 45 500)
@ FM TUNER SECTION
87.50~108.00 MHz
87.525~108.025 MHz (+25 kHz shift)
Frequency range
Sensitivity 1.2 uV (IHF, usable)
S/N 30 dB 1.1 pV (75Q)
S/N 26 dB 1.0 pV (75Q)
S/N 20 dB 0.9 wV (75Q)
IHF 46 dB stereo quieting sensitivity 28 pV/75Q
Total harmonic distortion
MONO 0.01%
STEREO 0.02%
Dynamic range 116 dB
Frequency response 4 Hz~18 kHz, +0.2 dB~ —0.5 dB
Alternate channel selectivity
normal +400 kHz 55 dB
super narrow +200 kHz 25 dB
Capture ratio 1.0 dB
Image rejection at 98 MHz 105 dB
IF rejection at 98 MHz 110 dB
Spurious response rejection at 98 MHz 110 dB
AM suppression 70 dB
Stereo separation
1 kHz 65 dB
10 kHz 50 dB
Carrier leak
19 kHz —70 dB
38 kHz —70 dB
Channel balance (250 Hz~6,300 Hz) +1.0 dB
Limiting point 0.75 pV
Technics
.. Scandinavia and
Switzerland
...United Kingdom
.. southeast Asia,
Oceania, Africa,
Middle Near East
and Central South
America
(K)(S) | [XL] ...Australia
(K)(S) | [EH] ...Holland
(K)(S) | [EB] ...Belgium
(K)(S) | [EF] ...France
(K)(S) | [PC] ...European Audio
Club
(K)(S) | [PA] ...Far East PX
(K)(S) | [PE] ...European Military
(K)(S) | [EGA]...F.R. Germany
Bandwidth
IF amplifier 180 kHz
FM demodulator 1000 kHz
Antenna terminals
75Q (unbalanced)
@ AM TUNER SECTION
Frequency range
(For Europe, South Africa and Australia)
522~1629 kHz (9 kHz-step)
530~1620 kHz (10 kHz-step)
(For Saudi Arabia and others)
531~1620 kHz (9 kHz-step)
530~1620 kHz (10 kHz-step)
Sensitivity (S/N 20 dB) 20 pV, 290 uV/m
Selectivity (£9 kHz) 55 dB
Image rejection at 999 kHz AO dB
IF rejection at 999 kHz 65 dB
@ GENERAL
Output voltage 0.6V
Power consumption 11W
AC 50 Hz/60 Hz, 110V/120V/220V /240V
430 xX 97 X 76mm
(16-15/16" X 3-13/16” x 1-7/8")
Weight 4.1 ky @ Ib.)
Power supply
Dimensions (WxXHXD)
¢ Specifications are subject to change without noice for
further improvement.
* Weights and dimensions shown are approximate.
Panasonic Tokyo
Matsushita Electric Industrial Co., Ltd.
1-2, 1-chome, Shibakoen, Minato-ku, Tokyo 105 Japan
Matsushita Electric Tradng Co., Ltd.
P.O. Box 288, Centry Osaka Japan

m@ CONTENTS
Page Page
SAFETY PRECAUTION .......... 000 ee eee eee 2 FUNCTION OF LIQUID CRYSTAL PANEL............ 16
FEATURES. core fe Scobie: Sa a heh ay eines WTA Eel a She BUA he 2 WAVEFORMS: 2.2555. cose gi 5 BG a ok Fhe eG wae ws Shei ts 17
LOCATION OF CONTROLS............0+ 00 eee 3,4 BLOCK DIAGRAM .......... 02 e eee eee 18,19
HOW TOOPERATE...........-02.-0 22 ee eeeee 4~6 CIRCUIT BOARDS AND WIRING CONNECTION
BEFORE REPAIR AND ADJUSTMENTS ............. 7 DIAGRAM 22. ieie 8 fee 8 es Ei ea ee 20 ~ 22
DISASSEMBLY INSTRUCTIONS ...............- 7~9 SCHEMATIC DIAGRAM ..........0 000 eee 23 ~ 28
HOW TO USE THE AMLOOP ANTENNA ............. 10 TERMINAL GUIDE OF TRANSISTORS, IC’S AND
MEASUREMENTS AND ADJUSTMENTS ......... 10 ~ 13 DIODES 5 i.e. 200 kee eS era eh ag te tera Bee aS 29, 30
FUNCTION OF TERMINAL (MPX IC301 -AN7471S)...... 14 RESISTORS AND CAPACITORS .............. 29 ~ 31
FUNCTION OF TERMINAL (PLL CONTROLLER IC902. REPLACEMENT PARTS LIST..............245 31~ 33
MIN 12919) cece seh a oe oS eee ww ee Sse st eb ees eS ete 14 EXPLODED VIEW... 1.2... ee tt te es 33, 34
FUNCTION OF TERMINAL (MICRO COMPUTOR !C903 -
MN1554STD)... 2.2... 2-0-0 eee ee 15
m@ SAFETY PRECAUTION
. Before servicing, unplug the power cord to prevent an electric shock.
. When replacing parts, use only manufacturer’s recommended components for safety.
. Check the condition of the power cord. Replace if wear or damage is evident.
After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.
. Before returning the serviced equipment to the customer, be sure to make the following insulation resistance test to
prevent the customer from being exposed to a shock hazard.
ORWNH
e INSULATION RESISTANCE TEST
1. Unplug the power cord and short the two prongs of the plug with a jumper wire.
2. Turn on the power switch.
3. Measure the resistance value with onmmeter between the jumpered AC plug and each exposed metal cabinet part, such as
screwheads antenna, contro! shafts, handle brackets, etc. Equipment with antenna terminals should read between 3MQ2
and 5.2MQ to all exposed parts. (Fig. A) Equipment without antenna terminals should read approximately infinity to
all exposed parts. (Fig. B)
Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.
Antenna
terminal
Exposed Exposed
metal metal
part part
Ohmmeter Ohmmeter
(Fig. A) (Fig. B)
Resistance = 3MQ2—5.2MQ Resistance = Approx oo
4. If the measurement is outside the specified limits, there is a possibility of a shock hazard. The equipment should be
repaired and rechecked before it is returned to the customer.
@ FEATURES
@ Newly developed LS! successfully incorporating both ®@ Self-computing RF tuning circuit capable of receiving
digital
(signal
control)
and
analog
(linear
&
signal
trans-
desired
station
under
the
best
conditions.
Mission) circuits in one body. @ FM-IF automatic IF band selecting function.
@ Extra-wide dynamic range of 116 dB (1 kHz), low dis- @ |nput/output terminal for personal computer con nection.
tortion of 0.01% {1 kHz), and stereo separation of @ Multi-function LCD intensive display.
65 dB (1 kHz). @ Reference signal 0.33 kHz record checking signa ! Output
@ Linear detector and linear demodulation digital detector
Circuits,
function,

m LOCATION OF CONTROLS
e Front Panel
Memory indicator
Channel display
Quartz-lock /FM muting off indicator
FM stereo indicator
Power
( stand-by -m on)
© Recording level check
FM signal-strength indicator
FM IF band selector
@ FM muting off/scan level selector
FM mode selector
@ FM IF band indicators (FM auto IF)
normal /a\:
This indicator will illuminate if the signal is strong and there
is little effect from interference.
super narrow /a\:
This indicator will iluminate if the signal is weak and/or there
is interference.
The
illumination
of
the
left
and/or
right
parts
of
the
indicator
indicates
that
interference
waves
are
present
within
+300
kHz
(left:
-, right:
+)
of
the
tuned
frequency.
@ FM muting off/scan level selector (muting)
This selector is used when releasing the FM broadcast
muting function and when setting the scan level for FM
broadcasts.
¢ Releasing the muting function (off)
In mountainous areas, etc., where broadcast waves are
weak, breakup in the sound can be lessened by lightly
pressing the button. When this is done, the function is
released only for the statin being received.
However, when a tuning button is pressed to begin
scanning, the former scan level will be used.
© Setting the scan level (scan level)
This level setting is effective only for the automatic preset
memory and auto tuning.
When the button is held down, “dB” will be displayed and
the numbers 30, 40, and 50 will be displayed in order.
When the desired level is reached, release the button.
The higher the level, the more noise is reduced. Stations
with good reception can use “ a high level”, but stations
below the set level cannot be received.
In order to receive these station, the level has to be reset.
no]
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nw c
Ss BS
1 ~
a =
oO n
Station
Preset tuning (1 ~ 16)
(FM)
iaie Band selectors
Control panel
door release
© Band selectors (band selector)
FM:
Press this button to listen to an FM broadcast.
+25 kHz:
The displayed FM frequency can be shifted by +0.025 MHz
(+25 kHz) in order to precisely align with the frequency of
the FM broadcast station.
lf the FM button is pressed until the final digit of the
frequency display is a small “5”, the FM frequency will shift
+0.025 MHz (+25 kHz).
To return to the original indication, press until the final small
“5” digit disappears.
AM:
Press this button to listen to an AM broadcast.
allocation:
A frequency step of either AM 9 kHz or AM 10 kHz can be
selected. Set to the appropriate position for your locality.
When the AM button is pressed slightly longer and then
released when the AL10” indication illuminates, the AM
frequency “step” will change to 10 kHz.
To return to the original 9 kHz, press the AM button slightly
longer, and then release it when the “AL9” indication
illuminates.
© Recording-level check button (rec level)
This button is to be used for adjustment of the recording
level when recording an FM broadcast.
When this button is pressed, the microcomputer functions to
emit a reference signal of precisely 333 Hz from the output
terminals of this unit. The word “CAL” (calibration) and then,
soon thereafter, “0.33 kHz” will be shown by the digital
display.
Adjustment of the recording level
Use the input-level control(s) of the tape deck to make the
adjustment while watching the recording-level meters.
e For VU meters and level meters:
Adjust so that the indication is about +2 VU or +2 dB.
e For peak-level meters:
Adjust so that the indication is about —2 dB.
Notes:
1) Because the ideal recording level is apt to vary depending
upon the program source and the characteristics of the
tape deck, the adjustment should be made by also
considering those factors.
2) Don't press the operation buttons of this unit during a
recording. If they are pressed, the recorded soundmay be
disturbed.

e Rear Panel Control input terminal
Output terminal
r—Computer control terminal
Voltage selector (AC 110/120/220/240V)
AC inlet (Except [EGA, XA] areas)
Main power
(Moff, -mon)
AM loop antenna terminal
AM antenna terminal
FM antenna terminal
(750, coaxial)
m HOW TO OPERATE
e Listening to radio broadcasts Important!
This antenna must be installed
ifj i isteni to receive AM broadcasts.
Turn the amplifier on, and prepare it for listening to radio AM Isopcantenia
broadcasts.
Station selection by using the tuning buttons:
@ Press either “FM” or “AM”:
@ Press the left button to change the frequency
downward, and press the right button to change
the frequency upward.
& Adjustment to FM broadcast signal e Auto tuning
strength is possible for automatic Press the button. When the
i fre indication begi
tuning. bes! requency eginsto
Press and hold the button change, release the button (a
(Will change to dB indication } broadcasting station will be
Release the button when the desired selected automatically). .
scan level indication (30, 40 or 50 dB) Repeat this operation until the
is displayed desired station is found.
(When the scan level is set, it will return e Manual tuning
to
frequency
display.)
Press
the
button
momentarily
wv (the frequency will change
«(( each time the button is
pressed) and tune to the
desired station.
YS Power: “on” (am )
Technics (uw sytnesize FMAM Stereo Tuner 87-07 ;
+ stereo quarts oon /FAt mating oft “ He tina satector |b ae
|
FO
|
i i
—————
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own wo
a Bang ee mernory
C= Station selection by using preset tuning buttons:
©
To
select
the
front
channels
(CH
1~8):
*°
To
select
the
back
channels
(CH
9~16):
Press Frequency stored in the Press
momentarily. memory and channel number slightly longer.
are displayed.
A |
Frequency stored in the
memory and channel number
are displayed.

e How to preset radio broadcast frequencies
Important!
This antenna must be installed
to receive AM broadcasts.
AM loop antenna
e Manual memory presetting
Stations can be freely preset to any desired channel.
This unit is used to preset as many as 16 radio broadcast
frequencies: FM/AM random presetting. After broadcast fre-
@ Before memory presetting
Each button is used to preset two stations.
quencies have been preset as described below, any desired
station can be quickly and easily selected by simply touching
one button.
Presetting front
channels (CH 1~8)
@ Memory presetting at
There
are
two
types
of
memory
presetting:
automatic
and
¢
Press
manual. Select whichever is preferred. momentarily.
e Automatic memory presetting
Beginning at the frequency indicated by the digital display, the FM broadcasting stations and AM broadcasting
stations will be automatically preset to “channels” 1 through 16 for FM and 9 through 16 for AM, respectively.
Note that in mountainous or remote areas, broadcasting stations which have weak broadcasting signals cannot be
Q Press the appropriate tuning button to tune to the desired broadcast:
Presetting back
channels (CH 9~16)
Press slightly
e Auto tuning
Press the button. When the frequency
indication begins to change, release the
button (a broadcasting station will be
selected automatically). Repeat this
e Manuai tuning wt
Press the button momentarily and tune to u(
the desired station (the frequency will
change each time the button is pressed).
operation until the desired station is found.
Adjustment to FM broadcast signal strength is possible for
automatic tuning.
Press and hold the button. (Will change to dB indication.)
Release the buiton when the desired scan level indication (30, 40 or
50 dB) is displayed. (When the scan level is set, it will return to frequency
automatically preset into the memory.
a Power: “on” ( B--m= )
Adjustment to FM broadcast signal strength is possible.
Press and hold the button. (Will change to dB indication.) Release the
button when the desired scan level indication (30, 40 or 50 dB) is
displayed. (When the scan level is set, it will return to frequency display.)
A broadcast signal stronger than the set level is memorized.
@ Press the “FM” or “AM” button:
To change the AM frequency by 10 kHz:
Press the “AM” button slightly longer and
release the button when the “AL 10”
is displayed.
wo PM/AM random ch preset tuning : a
display.)
Power: “on” ( Bm )
@ Press the “FM” or “AM” button.
To change the AM frequency by 10 kHz:
Press the “AM” button slightly longer and
release the button when the “AL 10”
is displayed.
Memory indicator
| Casein: Syrtnemiver FM/AM Stereo Tuner 8-4
ert cK/F MM mang off
ni me ci
Cy
-_ FM/AM fandom i6ch praset tuning ~
digest Ate oe 16 aid %
=
or)
Confirm the names (call signs, etc.) of the broadcasting
stations which are preset to each channel, and enter them on
the station memory file sheet.
To check the front channels (CH 1~8):
Press Frequency stored in the
momentarily. memory and channel number
ley Press. When the frequency
indication begins to
change, release.
While the memory indicator is illuminated,
press the button of the desired channel.
Press momentarily, and then
release.
(The memory indicator will
beg are displayed.
A
To check the back channels (CH 9~16):
Frequency
stored
in
the
order.
Press slightly
longer. memory and channel number
are displayed.
(The frequency will change upward,
and the automatic presetting will begin
with the broadcasting station of the
lowest frequency and will continue in
Note that the channel display
illuminates each time a broadcast
station is preset in the memory,
thus indicating which “channel” has
been preset.)
7
t
D2
on]
My
(4) © To preset FM broadcasting stations: Set to 87.50 MHz.
® Topreset AM broadcasting stations: Set to 522 kHz (or 530 kHz).
@ Press the button and
hold slightly
(frequency will change
continuously).
@ Release it at 87.50 MHz for FM or
522 kHz (or 530 kHz) for AM, and
then press the button again
momentarily
(frequency change will stop).
@ Press the button
momentarily (frequency will change
each time the button is pressed), and
tune to one of the above frequencies.
© To preset channels 1 through 8:
x Press the button momentarily, and then
Ci release. (Preset channel number is
displayed on the channel display.)
© To preset channels 9 through 16:
- ae Press the button slightly longer, and then
release. (Preset channel number is
displayed on the channel display.)
When the button is pressed, the memory
indicator illumination will stop, and the
presetting is complete.
Note:
1. If the memory indication illumination
stops before you press the button, once
again repeat step (5) and then step (6).
2. If a new broadcasting station is preset
into a channel, the broadcasting station
which was previously entered in that
channel will be automatically erased.
illuminate for approximately
4 seconds.)
4
A
Note:
If the button is pressed continuously,
the frequency will begin to change,
and the memory will be preset
automatically.
To stop the automatic memory
presetting, once again press either
the “up” button or the “down” button.
7) Enter the name (call sign, etc.) of the preset broad-
casting station on the station memory file sheet.
This completes the procedures for presetting radio broad-
cast frequencies. The other preset-tuning butfons can be
preset in the same way by following steps (2) through (7).

ST-G7 ST-G7
m BEFORE REPAIR AND ADJUSTMENT
The power switch of this unit is located on the secondary side of power transformer. So, be sure to disconnect
the power cord from the socket before starting the repair work. Also, when repairing the digital circuit, discon-
nect the power cord and then short-circuit across the gold capacitors (C920, C921, 2.3 V 3.3F) with a resistor
(10 ohms, about 1 W) to discharge the voltage.
m DISASSEMBLY INSTRUCTIONS
ee] How to remove the cabinet | How to remove the bottom board
Procedure
2
@ Remove the 11 setscrews. (Q@~ @)
Front pane}
Cabinet
Rear panel
1. Pull out the 5 connectors. (J8, J9, J11 and 2 lamp con-
nectors)
2. Remove the 7 setscrews. (Q@~ @)
3
Procedure
1=3
Connector terminals (J8, J9, J11) as viewed
from above with cabinet removed,
Lamp connectors for LCD
J11\, 3g
|
\ \ im) 9
A ay 7)
Front panel
Bottom board
@ Remove the 8 setscrews. (Q@~ @)
ae No. How to remove the sub panel
Procedure
1=>3=p4
1. Remove the 2 setscrews. (@, @)
2. Remove the lamp case and liquid crystal panel P.C.B.
Front panel
Liquid crystal
panel P.C.B.
: Z |
Liquid crystal! |
panel P.C.B.
Procedure
1939495
1. Remove the ornament.
2. Remove the 4 setscrews. (Q@~ @)
3. Remove the 3 setscrews. (@ ~ @)
Switch P.C.B.
Selector button

Ref. No.
6
How
to
remove
the
LCD
panel
@
Remove
the
1
setscrew.
(@)
Procedure
1—>3m>6
1,
Remove
the
2
setscrews
(@
,@)
3)
LCD
panel
receptacle
2. Remove the lamp case and liquid crystal panel P.C.B.
Filter
Front
panel
Bracket
Lamp
a
Oe
ay
Liquid crystal
panel P.C.B.
@ Remove the diffusion plate and liquid crystal panel
ins How to remove the glass door P.C.B. from the LCD panel receptacle.
Flat-head screwdriver LCD panel
Procedure a LCD panel
1.
Remove
the
4
setscrews.
(@~@)
receptacle
1=> 3 =>7 conalive rubber
2. Turn the glass door hinge counter-
clockwise (( ).
3. When disassembling or assembling the
movable bodies A & B, apply GREASE
6 to the parts shown in @ ~@.
Liquid crystal
panei P.C,B,
Conductive
rubber Diffusion
plate
Front panel Caution:
Never touch the LCD panel, electrode, conductive
rubber and liquid crystal panel P.C.B. electrode with
bare hand.
(Movable body 8)
@ Apply GREASE 6
to these parts.
@ Apply GREASE 6
to these parts.

m HOW TO USE THE AM LOOP ANTENNA
Find
the
best
reception
position
for
the
FM
antenna,
and
then
fix
2.
When
attaching
the
antenna
to
the
rack.
it
in
place ona
wail,
the rack, or
the
unit.
AM
antenna
holder (A)
(included)
Pay attention to the following points when attaching the
antenna.
1) Find the height and direction of the antenna where
reception is best and then fix it vertically to the wail, rack,
etc.
2)Do
not
attach
it
horizontally
(to
do
so
would
impair
reception).
3)
Do
not
attach
it
close
to
meta!
surfaces,
power
cords,
or
speaker
wires
(to
do
so
would
result
in noise).
4)
Do
not
attach
it
close
to
a
tape
deck
(when
the
tape
deck
is
being used, chirping or beeping sounds may be received).
3. When attaching the antenna to the unit.
AM antenna holder (B) (included)
a
CK
Rear panel AM loop antenna
1.
When
attaching
the
antenna
to
a
wall,
column.
of
the
unit
<~
(included)
AM loop antenna
(included) 4. If a hook is used
(if the holder can’t be attached by screws)
Hook (option)
AM antenna
holder (A)
(included)
AM loop antenna
(included)
m MEASUREMENTS AND ADJUSTMENTS
AM ADJUSTMENT
* Setting and Equipment used
1. ACelectronic voltmeters (EVM). 5. Output of signal generator should be no higher than necessary.
2. AMsignal generator (AM-SG). to obtain an output reading.
3. Set Band selector to ‘AM (allocation 9 kHz)’’ position. 6. Use a non-metal screwdriver for the adjustment.
4. Maintain line voltage at rated voltage.
AM SIGNAL GENERATOR DISPLAY
FREQUENCY PREPARATIONS PARTS ADJUSTED ADJUSTING PR OCEDURE
CONNECTION FREQUENCY
Step
No. AM-IF ADJUSTMENT
Connect AM-SG to
AM antenna terminal * Adjust the input frequency
through 200pF aoe is Prequeniey of | Connect AC EVM or T7201 (AM 1 st IFT) and adjustment points so
: % Mod, non-inter- scope to “OUTPUT
capacitor. Common to with 400 Hz) ference terminals that the output becomes
1 chassis. (Powerful input) : maximum,
(Refer to Fig. 1)
AM-RF ADJUSTMENT
| Except [XA]
area
522 kHz eating [XA] Connect AC EVM or 1. Adjust for max imum output,
2 [XA] area 522 kHz scope to “OUTPUT” L203 (ANT Coil) 2. Adjust core of L203 by
531 kHz terminals. screwdriver.
(30% Mod, Lees
Connect AM-SG to with 400 Hz) | 991 zl
i oeoeee 612 kHz Connect AC EVM or 1, Adjust for max imum output.
3 eapscny Caomimon'to (30% Mod. 612 kHz scope to “OUTPUT” L202 (ANT Coil) 2. Adjust core of L202 by
chassis (Weak input) with 400 Hz) terminals. screwdriver,
(Refer to Fig. 1) 1. Adjust for max imum output.
1503 kHz Connect AC EVM or cT201 2, Repeat steps (2, 3) and (4)
4 (30% Mod. 1503 kHz scope to “OUTPUT” (ANT Trimmer) until the frequency correctly
with 400 Hz) terminals. matches the frequency
display.

adjustment.
[FM ADJUSTMENT
* Setting and Equipment used. * Preparation of FM signal generator (FM-SG)
1. FM signal generator (FM-SG), 1. The standard input of the set is 60 dB (1 mV), 400 Hz, 100%
2. Distortion analyser. modulation (Because of attenuation, using coaxial cables, SG
3. Oscilloscope output must be 6 GB plus, That is, when input 60 dB SG
4. AC and DC electronic voltmeters (EVM). output is to be 66 dB.)
5. Frequency counter (19 kHz and 108 MHz measurable).
6. Set band selector to ‘‘FM" position.
7. Set FM mode selector to ““mono” position. * When the frequency is changed, muting is automatically turned on.
8. Other setting are the same as in AM adjustment. So, be sure to turn it off by the FM muting off/scan level selector switch,
9. Set IF band selector to: ‘‘normal” position. Also, make sure that the FM IF band is at “‘normal’’.
=
FM SIGNAL GENERATOR DISPLAY
PREPARATIONS PARTS ADJUSTED ADJUSTING PROCEDURE
CONNECTION FREQUENCY | FREQUENCY
rbd FM MONO DISTORTION ADJUSTMENT
100.10 MHz Connect DC VEM 1. Adjust T101 core so that
m between PGA and set tile voltage measured in signal
5 pirates 100.10 MHz through choke T101 {Discri. IFT) mode is 0 mV in 300 mV
wilt # coil. (Refer to Fig. 2) range.
Connect
FM-SG
to
100.10
MHz
i
|
Connect
AC
EVM
1.
Adjust
for
maximum
output.
, a :
Bi)
martene
carried.
Oe
Me
|
doasianare:
«|
Poteet
MMMM
2m
Irie
Sea
fray
|
abet
care
ch
102
ty
antenna terminal.) (Refer to Fig. 3)
Connect DC VEM 1. Adjust VR102 so that
100.10 MHz VR102 :
7 (0% Mod. 100.10 MHz__| Petween (Pulse count duty voltage measured in
with 400 Hz) and ground, adj.) signal mode isO mV in
(Refer to Fig, 4.) J. 300 mV range.
Short-circuit between MGW and by
jumper wire only during FM-RF adjustment, FM-RF ADJUSTMENT
and be sure to open the circuit during adjustment
other than FM-RF.
1, Scat sc Rey
5 EGET and bE by
Seem, | areata brow ve Bos
8 referririg to’ Eid: 5 (100% Mod, 87.50 MHz 2. Connect DC EVM L6 (OSC Coil) reading on DC EVM.
19 g. ©. with 400 Hz) between fiGAI (+)
(Weak input)
and Ground.
LIOANT Coil} | 1+ Adel woak input ee that
90.10 MHz L1 (ANT Coil
cm | (100% Mod. | 90.10MHz | sgcyepysrserminals, | L3. (ANT Coil) apd auicald acl
g | Connect FM-SG to with 400 Hz) erminals. | 1a (ANT Coil) 2. Make the adjustment so that
antenna terminal T1 (FM 1st IFT) the output wave form is ver-
referring to Fig. 6. tically symmetrical. (Fig. 7).
(Weak input) Tea + 3. Hepes! ihestps (8), (9} and
: 2 10) until the frequency cor-
10 (100% Mod. 106.10 MHz Tent ea CT1 (OSC Trimmer) rectly matches the frequency
with 400 Hz) ‘ display.
PILOT CANCEL ADJUSTMENT
Connect FM-SG to
FM antenna terminal 100.10 MHz : : Make the adjustments so that
‘ : Connect scope L301 (Pilot filter) F
11 referring to Fig. 8. (0% Mod. : the output waveform is
(Apply 60 dB to with 400 Hz) 100.10 MHz between and VR103 (Pilot Cancel) | i pelscring se
antenna terminal.) (L+R) Ground. Fig. 9.
(Pilot 10% Mod.
stereo signal.) L
ess +
STEREO DISTORTION ADJUSTMENT
Connect FM-SG to T
FM antenna terminal 100.10 MHz Connect distortion
refferring to Fig. 10. (90% Mod analyser to “OUTPUT” FE Adjust T1 and T103 core so that
12 (Apply 60 dB to ith ps Hj ) 100.10 MHz terminals of the set EM clea distortion of right and left
antenna terminal.) iL or R mites through low-pass filter. 7 channels are minimized.
(Pilot 10% Mod. (fc = 15 kHz~19 kHz)
stereo signal.)
ST-G7 ST-G7
Note: FM IFT (2nd) [T102], FM 2 nd IF filter [T104, T105] and FM DET filter [L302, L303] have been already adjusted, and require no
FM SIGNAL GENERATOR
: EHeQUENCcY | PREPARATIONS || PARTS ADJUSTED | ADJUSTING PROCEDURE
2.3. CONNECTION FREQUENCY FM Signal gene
tep =
No. SEPARATION ADJUSTMENT KS
Connect EM-SG to 1. Adjust VR303 so that R
: output is minimized when (750)
Bete aay 100.10 MHz Sd eac ta sede stereo modulator is in L e OO
pone (90% Mod. VR303, VR304 (L ch. modulation) mode,
13 {Apply 60 dB to antenna f 100.10 MHz of the set through : °
ermine with 1 kHz) lowe-bese titer (Separation) 2. Adjust VR304 so that L
(Pilot 10% Mod Reta rupae! (fo = 15 kHz ~19 kHz) SutoMs etnies Wien
stereo signal.) stereo modulator is in
:
R
(R
ch
modulation)
mode.
SIGNAL STRENGTH LEVEL ADJUSTMENT
1
1. Change LCD display from
. ee frequency to dB by pressing
onnect -SG to the FM signal button, :
FM antenna terminal. 100.10 MHz VR101 2. Adjust VR101 so that 50 dB FM Signal gener
14 (Apply 50 dB to (30% Mod, 100.10 MHz (Signal strength < indicated
antenna terminal.) with 400 Hz) level) 3. Make sure that the signal bh
strength level is 22 ~ 38 dB
when the input is 30 dB. (750) ff
e OO
e Adjustment points
612 kHz 1503 kHz
19 kHz R—-L L-R FM AM ANT AM ANT
Filter separation separation discri. IFT coil trimmer FM Signal gene
L301]
R304] [VR303]
Computer Control Output | AM ANT
control input terminal), " EXT
AC
inlet
terminal
terminal
——,
{|
Loop
L302 NO ADJUSTMENT
L303 NO
ADJUSTMENT
ADJUSTMENT
T1085 NO TPI03
Ground point
450 kHz
FM ANT
(75Q)
[vRI03 [ti03] [vrioi}] [t2o] [ctr]
19 kHz Pulse count FM IFT Signal strength AMIFT FM 1st FM 1 st
cancel adj. duty adj. (3 rd) level adj. (1 st) Osc. OSC coil
trimmer
AM Signal generator (AM-SG)
r
oO
O' 0
°
OC
AM antenna terminal
7 Output
aad terminal
Capacitor
(200pF)
[Fig. 1] [Abb. 1]
Oscilloscope
me FM ANT
@ S coil
{ L10 |
‘iz | | AM RF coil
L203} 522kHz
FM ANT coil
T coil
T coil
FM Signal gener:

BR
' adjusted, and require no
|, 400 Hz, 100%
axial cables. SG
t60dB SG
omatically turned on.
ff/scan level selector switch.
ormal’’.
\DJUSTING PROCEDURE
Adjust T101 core so that
voltage measured in signal
mode is O mV in 300 mV
range.
Adjust for maximum output.
Adjust core of T103 by
screwdriver.
Adjust VR102 so that
voltage measured in
signal mode is O mV in
300 mV range.
Adjust L6 for 3.0V
reading on DC EVM.
Add weak input so that
noise is included in the
output wave form,
Make the adjustment so that
the output wave form is ver-
tically symmetrical. (Fig. 7).
Repeat the steps (8), (9) and
(10) until the frequency cor-
rectly matches the frequency
display.
ike the adjustments so that
> output waveform is
nimum referring to
y. 9,
just T1 and T103 core so that
tortion of right and left
annels are minimized,
Step
No.
13
14
Control
Output
|
AM
ANT
/FM
ANT
input
terminal
Loop
EXT
(75)
terminal -—
—
=
FM
ANT
@ S coil
a
mzsr| | AM RF coil
L302
NO
ADJUSTMENT
Oa
lak
L203]
522kHz
Z)
L303
NO
FM
ANT
coil
ADJUSTMENT
Computer
control
AC inlet terminal
T105 NO ADJUSTMENT
ADJUSTMENT Mae
Ground point
450 kHz
| T201
19 kHz Pulse count FM IFT Signal strength AM IFT FM 1 st FM 1 st
cancel adj, duty adj. (3rd) level adj. (1 st) OSC. OSC coil
trimmer
AM Signal generator (AM-SG)
Oscilloscope
AM antenna terminal
¢ Output
oe terminal
Capacitor
{200pF)
[Fig. 1] [Abb. 1]
DC EVM i
FM
SIGNAL
GENERATOR
DISPLAY
Cc
Oscilloscope
FREQUENCY PREPARATIONS PARTS ADJUSTED ADJUSTING PROCEDURE —
CONNECTION
FREQUENCY
FM
Signal
generator
(FM-SG)
“6
ae
SEPARATION ADJUSTMENT
TEK I =
1. Adjust VR303 so that R
Connect FM-SG to te Te at ae |
FM
antenna
terminal
Connect
AC
EVM
to
output
is
minimized
when
i730)
: : 100.10 MHz i i : stereo modulator is in L
referring to Fig. 11. (90% Mod. erat Pit oe ena u G04 (L ch. modulation) mode.
(Apply Poe RMEPNE | nthe KHz) Pa ee (Separation) 2. Adjust VR304 so that L 4-68 sees
tees
oe
Mod.
(L
or
R
mode)
(fe
=
15
kHz
~19
kHz}
ee
FEM
antenna
_(SLOx10!-20)
FM
antenna
terminal
(750)
stereo signal.) R (R ch modulation) mode terminal (750) Fig. 3 Abb. 3
as ls : [Fig. 2] [Abb. 2] [Fig. 3] [ ]
SIGNAL STRENGTH LEVEL ADJUSTMENT
1. Change LCD display from DC EVM
frequency to dB by pressing pra
Connect FM-SG to the FM signal button. .
EM antenna terminal. aaa ree i cee 2. Adjust VR101 so that 50dB| FM Signal generator (FM-SG) FM Signal generator (FM-SG)
(Apply 0 dB to oa aed Hz) 3 ‘eet g is indicated. ©
antenna terminal.) 3. Make sure that the signal
strength level is 22 ~ 38 dB TP302 & ee ee | ees
when the input is 30 dB.
Z
Ground
Ground
‘eae eee
FM
antenna
terminal
(75)
on
antenna
terminal
Q)
Adjustment points [Fig. 4] [Abb. 4]
612 kHz 1503 kHz {Fig.5] [Abb. 5]
19 kHz R-L L-—R FM AM ANT AM ANT
Filter
separation
separation
discri.
IFT
coil
trimmer
FM
Signal
generator
(FM-SG)
.
Noise
Tior | L202] [er201 Oscilloscope kar ee
Output
goo dO: terminal
FM antnna terminal (752)
[Fig. 6] [Abb. 6]
Noise
AF output wave form
[Fig. 7] [Abb. 7]
Oscilloscope
FM Signal generator (FM-SG)
pee agett
[Fig. 9] [Abb. 9]
FM antenna
terminal (750)
[Fig. 8] [Abb. 8]
FM Signal generator (FM-SG) Distortion analyser
Output
B O° OD terminal
FM antenna
terminal (752)
[Fig. 10] [Abb. 10]
Low pass filter
FM Signal generator (FM-SG) ACEVM ACEVM
FM antenna terminal (7522)
[Fig. 11] [Abb. 11]