Technics SA-CH750 User manual

Service
Manual
Tuner
Amplifier
Tuner
Amplifier
SA-CH750
Colour
eFor (E), (EB), (EG) areas
SL-CH750 SH-CH750
Remote Control
Transmitter
+
| (Kyi cent acces Black Type
Areas
Suffix for
Model No. Colour
SB-CH750A/CH755 RS-CH750 SA-CH750 SB-CH750A/CH755
eFor (GC), (GN) areas
Great Britain
Remote
Control
SL-CH750
SH-CH750
Germany
and
Italy
(k)
Transmitter
Asia, Latin America,
Middle Near East and
Africa
Oceania
System: SC-CH750
SB-CH750 RS-CH750 SA-CH750 SB-CH750
Because of unique interconnecting cables,
hen a component requires service, send
r bring in the entire system.
SPECIFICATIONS
(DIN 45 500) ie ee Fe ows,
@ Main Amp. Section
Power output
DIN 1 kHz THD 1%
both channel driven
For (GC), (GN) areas
SFP,mode1kHzTHD1% _ [toevn nail AN TUNER SECTION
MAIN | Eee NEE ncy range
SURROUND 2x5 W (8Q) MW
Total harmonic distortion For (E), (EB), (EG), (GN) areas 522-1611 kHz (9 kHz steps)
Rated power at 1 kHz 1% (6) 530-1620 kHz (10 kHz steps)
Half power at 1 kHz 0.09% (6Q) For (GC) area 531-1602 kHz (9 kHz steps)
Load impedance 530-1600 kHz (10 kHz steps)
MAIN 6-80 LW
SURROUND 8 For (E), (EB), (EG), (GN), areas 9 144~—288 kHz Q kHz steps)
S/N (rated power) 84 dB For (GC) area 153-279 kHz @ kHz steps)
Frequency response 40 Hz—30 kHz (—3 dB) Sensitivity (S/N 20 dB)
MW 500 uVv/m
m@ FM Tuner Section LW 50 uV
Frequency range 87.50 MHz—108.00 MHz (0.05 MHz steps)
Sensitivity 1.8 pV (IHF, usable) @ Timer Section
S/N 26 dB 1.5 yV (75Q) Clock Quartz-lock type
S/N Function 24-hour programmable; Play trmer (1 time)
MONO 70 dB (75 GB, IHF) Rec trmer (1 time)
Stereo separation at 1 kHz 35 dB Sleep (120 min. 1 min. intervals)
Antenna terminal(s) 75Q (unbalanced) Setting 1 minute—23 hours 59 minutes (1 min. intervals)
Sound processor | Tuner amplifier | Compact disc player | Cassette deck Speakers
*SB-CH750A ............ (E), (EB), (EG) areas
SC-CH750 SH-CH75' SA-CH750 SL-CH750 RS-CH750 *SB-CH795 cesccds 2 esate aa Baytthes Switzerland only
SB-CH750 ................ (GC), (GN) areas
*Magie in PAES
Technics

2
“SA-CHT750 |
™@ GENERAL Dimension (WxHxD) 270119334 mm
Power consumption 175W Weight 5.5kg
Power supply
For (E), (EG) areas AC 50/60 Hz, 230 V Notes:
For (EB), (GN) areas AC 50/60 Hz, 230 V-240 V 1. Specifications are subject to change without notice.
For (GC) area AC 50/60 Hz, 110/127/220/240 V 2. Weight and dimensions are approximate.
3. Total harmonic distortion is measured by the digital spectrum
|
co
NTE
NTS
analyzer.
Page Page
@BEFORE REPAIR weci5 Sa cds eee eee ts as bee SO 2 @SCHEMATIC DIAGRAM ............002 20 ce cee eee 14~22
e@PROTECTION CIRCUITRY .......... 2.00. e eee eee eee 2 ePRINTED CIRCUIT BOARD DIAGRAM................ 23~27
@ACCESSORIES............ 00. cece cece eee eee reer eeeee 2,3 e@WIRING CONNECTION DIAGRAM .............00000 eee 28
@LOCATION OF CONTROLS ..... 1. eee eee 3,4 @BLOCK DIAGRAM............. 0.00 c ccc een eee 29~31
e@STACKING THE COMPONENTS .............. 000 cece eee 5 @FUNCTION OF IC TERMINALS ...............000..0 0000s 32
@CONNECTIONS ......... 2 cece eee ne eeee 6~9 @REPLACEMENT PARTS LIST ..............0.000 eee 33~38
e@SETTING THE TIME OF DAY ......... 0.0 cece eee eee 9 e@CABINET PARTS LOCATION .............- 0.0. eee eee e eee 39
e@DISASSEMBLY INSTRUCTIONS .................04. 10~13 @PACKAGING .... 0. cece cece cence teen ne eeeneeatens 40
m@ BEFORE REPAIR
(1) Turn off the power supply. Using a 10Q, 10 W resistor, connect both ends of power supply capacitors (C701, C702) in order to discharge the
voltage.
(2) Before turning the power supply on, after completion of repair, slowly apply the primary voltage by using a power supply voltage controller to make
sure that the consumed current at 50/60 Hz in NO SIGNAL mode is mode should be shown below with respect to supply voltage 230 V/240 V.
Power supply voltage AC 230 V AC 240 V
Consumed current 50 Hz 130~230 mA 110~210mA
m@ PROTECTION CIRCUITRY
The protection circuitry may have operated if either of the following conditions is noticed:
“No sound is heard when the power is switched ON.
*Sound stops during a performance.
The functions of this circuitry is to prevent circuitry damage if, for example, the positive and negative speaker connection wires are “shorted”, or if
speaker systems with an impedance less than the indicated rated impedance of this unit are used.
If this occurs, follow the procedure outlined below:
1. Switch OFF the power.
2. Determine the cause of the problem and correct it.
3. Switch ON the power once again.
Note:
When the protection circuitry functions, the unit will not operate unless the power is first switched OFF and then ON again.
| ACC ESSORI ES Check the packing carton for these accessories.
(RJA0019-2K) for (E), (EG), (GC) areas
(VJA0733) for (EB) area
(SJA173) for (GN) area
ie ieee Hong Mei See daca hee Ae ee 1 pe. eSurround speaker cords. ... 0.2.0... cece ee eee eee 2 PCS,
(RJL1P001B25) for (GC), (GN) areas
(RAK-SC709WH) Note: These are available on sale route.
Remote control transmitter... 2.2. eee eee 1 pe. Remote control batteries
UM-4, AAA, RO3 2... eee 2 pcs.
eFlat cable @Antenna:holder-2.: 2304-4 e a shateaies f4 Rs eee ea SES 1 pe.

(SPB1163T)
(RSA0007) for (E), (EB), (EG) areas
(RSA0006) for (GC), (GN) areas
(SWXS257M)
e@Speaker cords 2.0.0.0... ec cee eee 2 pcs.
m@ LOCATION OF CONTROLS
@ Power “STANDBY (5/ON” switch
(POWER, STANDBY (/ON)
This switch switches ON and OFF the secondary circuit power
only. The unit is in the “standby” condition when this switch is
set to the STANDBY © position. Regardless of the switch
setting, the primary circuit is always “live” as long as the
power cord is connected to an electrical outlet.
@) Timer play button ({ PLAY)
Press to confirm, exit or reset the play timer.
@) Timer recording button (] REC)
Press to confirm, exit or reset the record timer.
| SA-CH750
O” & (XTN3+10AFZ)
e@Mounting screws .. 0... ee eee 2 pcs.
eAttachment plug ......... 2.0... eee ee eee 1 pe.
(SJP9009) for (EB) area
& &y (SJP5213-2) for (GC) area
e@Power plug adaptor............... 0.0000 eee eee eee 1 pe.
Note:
The configurations of AC power supply cord and FM indoor antenna
differ according to area.
VOLUME
=eesece
savor OO eee
© Volume level control (VOLUME)
Turn to adjust the volume level.
Note that —- dB is the lowest volume setting and 0 dB is the
highest.
© Input select buttons
(TAPE, CD, TUNER, DAT, VCR, VDP, PHONO)
Press to select the sound source.
© Remote control signal sensor (SENSOR)
Receives the signals from the remote control.
@) Headphones jack (PHONES) (23.5, 32)
Piug headphones cord into this jack.
SA-CH750
Clock/timer button (CLOCK/TIMER)
Press to select the clock set mode or desired timer mode.
©) Timer select buttons (WV SELECT A)
Use when setting the current time and timer.
Setting button (SET)
Press to set the present time in the clock mode, or set the
various selection in the timer mode.
@}) Preset memory button
(MEMORY, -MANUAL, —AUTO)
Press to put a broadcast station into the memory.
(2) Band select/allocation change button
(BAND, -BAND —ALLOCATION)
Press to select the MW, LW or FM radio band.
Press and hold to change the MW frequency step.
@® Preset tuning buttons (WV PRESET A)
Use to select channel number for a broadcast station which
has been stored in the tuner’s memory.
Tuning buttons (WV TUNING A)
Use to tune in a desired broadcast station.
The functions indicated by the numbers with black background (for
example @) can also be activated from the remote control.
eDisplay section
@) © ‘ Qa® @ @ @
SUNMON TUE WED THUFRISATISLEEP | IpGyVCH VDE* VOLUME
Faccc=ri (YEG TOPLAYION OFF" QUARTZLOCK =bqSMqx
TRAC! TaOPT Wn tres MEMO CH =. =
“ahd LLP LIA ALT ALE WA aie (=) =; = |=
Sh on a oo co EE Sk ae
0) 3) @ 2) @ a8) Q9
(5) Timer mode indicators (© REC, [ PLAY)
[4] REC: Lights when you have set the record timer mode.
[4 PLAY: Lights when you have set the play timer mode.
Day indicators (SUN-SAT)
Shows the day of the week or the day the timer has been set
for.
(7?) Sleep timer indicator (SLEEP)
Lights when you have set the sleep timer mode.
Timer on/off indicator (ON, OFF)
Lights together with the setting time to show the timer ON time
and OFF time.
BGV (background visual) indicator ( )
Lights when listening to audio sound source.
@0) Visual source indicators (VCR, VDP)
Lights to show it is possible to enjoy BGV (Back Ground
Visual) if you connect video deck or video disc player to this
system.
@) Quartz lock indicator (QUARTZLOCK)
Lights when you precisely tune in a broadcast station.
@2) Volume level display (VOLUME, MAX, MIN)
Shows the volume level.
@3) FM STEREO/MONO indicator
(MONO, STEREO)
“STEREO” lights when an FM stereo broadcast is being re-
ceived. If you press FM mode button on the remote control to
select monaural mode, “MONO” lights.
®
Aipha-numeric display
Shows the selected source, present time, and the contents of
the timer setting, received frequencies, volume level.
Memory indicator (MEMO)
Lights when the preset memory button is pressed.
Preset channel display
Shows the preset channel you select.
Channel indicator (CH)
Lights when the unit is in the preset tuning mode.
Balance display (L, R, BALANCE)
Shows the left-right volume balance.
® ® © ©
©
Muting indicator (MUTING)
Lights when you activate the muting mode.

SA-CH750 SA-CH750
m CONNECTIONS
m STACKING THE COMPONENTS
Install the various components as shown below.
@ Horizontal stacking ©The terminals for surround speaker
cords (5) are only for (GC), (GN) areas
For (E), (EB), (EG) areas
Place both speakers so that the tweeter comes outward.
(Back of product)
{Komponentens bagside)
(Produktets bakside)
CLASS 1
[fa | LASER PRODUCT
T_] LUOKAN 14 LASERLAITE
KLASS 1 LASER APPARAT
Right speaker
SL-CH750
Compact disc player
SH-CH750
Sound processor
SH-CH750 SL-CH750 Bs
@ Vertical stacking
SH-CH750
Sound processor
Cassette deck Tuner amplifier SB-CH750A
RS-CH750 SA-CH750 or
SB-CH755
SA-CH750
Tuner amplifier
SL-CH750
Compact disc player
For (GC), (GN) areas
Place both speaker so that the surround speaker.
comes outward.
Right speaker
RS-CH750
Cassette deck
SL-CH750 SH-CH750
Compact disc player Sound processor
© eoo
= = | |S
1
Connect
the
fiat
cable.
2
Connect
the
FM
indoor
antenna.
Install the antenna on a wall at a height and in a direction
Connecting Disconnecting which result in the best reception.
Cassette
deck
Tuner
amplifier
SB-CH750
a
oa
=)
:
=
Adhesive
tape
RS-CH750 SA-CH750
—— FM indoor antenna PANT,
(included)
Hold the connector with the recessed part up and press in at
@ Left speaker For (E), (EB), (EG) areas the center until you hear a click.
First connect the blue-colored connector to the terminal of the
@ Television set
(not included)
® This system
sound processor (A), then connect the rest in the order B, C,
D.
Route the cable horizontally (underneath the heat outlet grille)
so that the side with the white-color lead is positioned at the
front.
After connection, fold and press the cable as flat to the back of
the unit as possible.
Led
The tip of the internal antenna wire should not come into
contact with any metal objects.
When you cannot get a good reception with this FM indoor
antenna, we recommend you install an FM outdoor antenna
(not included). Disconnect the FM indoor antenna if you install
an FM outdoor antenna.
Heat outlet grille
Do not try connecting or disconnecting the flat cable
while the power is switched to ON.
To produce a better stereo sound, install both speakers away from
the system. ;
This speaker system has built-in surround speaker, so you can Surround sound effect differs according to where you install the
easily enjoy the surround sound. surround speakers. Install them as you like.
=5-
m6

3 Connect the LW/MW loop antenna.
1. Attach the antenna holder with screws (included) to the rear
panel of the sound processor.
2. Clamp the antenna to the antenna holder and connect the
antenna terminal to the rear panel of the tuner amplifier.
3. Position the loop for the best reception.
You may attach the LW/MW antenna holder to a rack or other
structure.
Notes:
To minimize noise pickup, keep the LW/MW loop antenna
away from the speaker cable, power cord, and metal sur-
faces.
For better reception, keep the LW/MW loop antenna cord
along
the
heat
outlet
grille,
and
away
from
the
flat
cable.
Antenna
Connection of speaker cables
1. Strip off the outer covering, and
twist the center conductor.
Make sure the bare ends of the wires are not unraveled.
(If they are, twist them tight again.)
3. Insert the wire to the rear panel
of the tuner amplifier, and close
the lever.
Notes:
©To prevent damage to circuitry,
never short-circuit positive (+)
and negative (—) speaker wires.
eBe sure to connect only positive (red) wires to positive
(+) terminals and negative (black) wires to negative
(—) terminals.
Note:
Be sure to connect speaker cables before connecting the AC
power supply cord.
2. Insert the wire to the rear panel
of the speakers, and then pull »>
down the lever.
SA-CH750
5 Connect the surround speaker cord.
For (GC), (GN) areas
Rear panel of Rear panel of
the Tuner amplifier the speakers
6 Connect the AC power supply cord after you
have connected all other cables and cords.
Insertion of Connector
Even when the connector is per-
fectly inserted, depending on the
type of inlet used, the front part of
the connector may jut out as
shown in the drawing.
However there is no problem
using the unit.
Connector
Approx. 6 mm
Appliance inlet
@ External unit connection
Surround speaker
Tuner amplifier
Right speaker Left speaker
(not included) (not included)
Notes:
Install each speaker left and right at the back of the listening space.
Be sure to connect both speaker systems. If only one side is
connected, no sound will be heard.

SA-CH750
Television
Television set (not included)
Video connection
cable (not included)
Sound processor
Center speaker for (GC), (GN) areas
Tuner amplifier
CONTROL
Monaural
L-type
cable
connection
(not
included)
cable
(not included)
Center speaker (not included)
(with the function of amplifier)
Household
AC outlet
AC power supply cord
Note:
When you use a center speaker which has not a built-in amplifier,
connect it to an another amplifier.
Video deck
Hi-Fi video deck (not included)
AUDIO VIDEO AUDIO VIDEO
INPUT =INPUT OUTPUT OUTPUT
(R)(L) (R)(L)
a6 ba
St
Video
connection
peaeags
cable
(not
included)
cable
Al
8
(R)(L) (R(L)
(not included)
Sound processor
When you use a monaural video deck, connect it with monaural
video connection cable.
Analog player
Analog player (not included)
OUTPUT
=
R) (L)
Stereo connection cable
(not included)
) 3
(L)
Sound processor
“GND” terminal
This terminal is for a ground wire use.

DAT (digital audio tape deck)
DAT (not included)
ANALOG INPUT
OUTPUT
Oo ©
(R) (L) (RR) (L)
Stereo connection cable
(not included)
(R) (tL) (R) (L)
DAT
PLAY (IN)
Sound processor
@ SETTING THE TIME OF DAY
1 24-68
3°5°/
These instructions explain how to set the time for 16:25 (4:25 p.m.)
on Wednesday.
Switch on the power.
1 Press CLOCK/TIMER to select ‘“‘CLOCK”’.
The display will show CLOCK.
The display will return to what was previously indicated if you
allow 7 or more seconds to elapse before you accomplish the
next operation.
2 Press SET.
The day indicator will start to flash.
SA-CH750
Video disc player
Video disc player (not included)
AUDIO VIDEO
OUTPUT OUTPUT
(R) (L)
Video connection cable
(not included)
Stereo connection cable
(not inlucded)
Sound processor
3 Press one of the SELECT buttons to select
“WED’’.
Flashing
Press SET.
Press one of the SELECT buttons io select
“4 6’’.
Going from 23:59 to 00:00 on the hour display willnot change
the day display.
ak
6 Press SET.
7 Press one of the SELECT buttons io select
95”
Going from 59 to 00 on the minute display will notchange the
hour display.
cio —<$_—
8 Press SET to finish setting the time.
After about 2 seconds, the display will return to vhat it were
before entering the clock setting mode.
To display the clock again, press CLOCK/TIMER. Thedissplay will
show “CLOCK”, and then clock will appear for 5 secons,
“E” appears on the display if the power cord has been oicee discon-
nected or there has been a power failure. If this happen, reset the
time.

SA-CH750 |
m@ DISASSEMBLY INSTRUCTIONS
“ATTENTION SERVICER”
Some chassis components may have sharp edges. Be careful when disassembling and servicing.
Removal of the Cabinet Ec Removal of the Front Panel Ass’y
1
Cabinet
1. Remove the 5 screws (@~@). 1. Remove the 3 screws (@~@).
2. Remove the cabinet in the direction of arrow. 2. Remove the front panel ass’y in the direction of arrow.
Main volume knob
1. Pull out the main volume knob.
2. Remove the nut.
Removal of the Rear Grill Ass’y
Procedure
154
Rear grill ass'y
2. Remove the 2 ribs.
1. Remove the 9 screws (@~@). 3. Remove the rear grill ass’y in the direction of arrow.
~10-

SA-CH750 SA-CH750
Removal
of
the
Headphones
Jack
Ref.
No.
Removal
of
the
Input/outout
Terminal
Removal
of
the
Fan
Ass’y
Ref.
No.
Removal
of
the
main
P.C.B.
P.C.B. 6 P.C.B. 12
Procedure
Procedure
Procedure
12535
124-6
3971112
Main P.C.B.
Flat cable
Fan ass'y
»)
e
Hol
|
Headphones jack P.C.B. npuvoutput
terminal P.C.B.
1. Remove the connector (JK351).
2. Remove the input/output terminal P.C.B. in the direction of 1. Remove the connector (JK351).
2. Remove the 3 screws (@~@). _ | 1. Remove the 4 screws (@~@).
arrow.
2. Remove the flat cable (J703-1, J703-2).
Ref. No. Removal of the AC Input Terminal Ref. No. Removal of the Power Transformer
7
P.C.B.
and
Tuner
P.C.B.
8
P.C.B.
(A)
m=
NOTE
[Bottom view]
elnsert the projection on the
Procedure
Procedure
Procedure
|
swhen
checking
the
soldered
surfaces
of
angle
into
the
hole
of
the
Projection
1457 1-2-8 | © 132411
Remove the headphones jack P.C.B. in the direction of arrow.
main P.C.B. and replacing the parts, do as bottom board ass'y and then ZN
313 shown below. install the Main P.C.B.
4 4 :
A Power transformer
Tuner P.C.B. P.C.B. (A)
m@ Removal of the AC input Terminal P.C.B. 1. Remove the 2 screws (@, @).
Remove the AC input terminal P.C.B. in the direction of arrow. 2. Release the claw.
3. Remove the 2 ribs.
m@ Removal of the tuner P.C.B. 4. Remove the power transformer P.C.B. (A) in the direction of
@ Remove the tuner P.C.B. in the direction of arrow. arrow.
Ref.
No.
Removal
of
the
Power
Transformer
Ref.
No.
Removal
of
the
Power
Transformer
9
P.C.B.
(B)
10
Procedure
1529
Flat cable
3. Remove the rib.
1. Remove the 4 screws (@~Q@). 4. Remove the main P.C.B. in the direction of arrow.
Front panel
ass'y
- ~ a r \ LL g ; =
~ > a W G.N.D. terminal
. 7 . | ‘Bp — he ' n
;
“a>
3
in
PC.B.
. Power transformer >. SS CZ Ss»
s P.C.B. (B) PSsZ Bottom board ass'y
1. Remove the flat cable (J703-1, 703-2). SF Femer manetomet
4. Connect the G.N.D. terminal to the bottom board ass’y by
2. Release the 2 claws. the lead wire.
3.
Remove
the
power
transformer
P.C.B.
(B)
in
the
direction
of
2.
Remove
the
rib.
5.
Reinstall
the
front
panel
ass’y
to
the
input/output
terminal
arrow.
e
Remove
the
4
screws
(Q@~@).
3.
Remove
the
main
P.C.B.
in
the
direction
of
arrow.
P.C.B.
his DS

SA-CH750
SA-CH750 |
sformer
sformer
sformer
et
Removal
of
the
Fan
Ass’y
ee
Procedule
Procedure
une:
13246
37311512
Removal of the main P.C.B.
Main P.C.B.
Flat cable
Fan ass'y
1. Remove the connector (JK351).
2. Remove the 3 screws (@~®).
1. Remove the 4 screws (@~@).
2. Remove the fiat cable (J703-1, J703-2).
m NOTE
elnsert the projection on the
angle into the hole of the Projection
bottom board ass'y and then AAs
install the Main P.C.B.
[Bottom view]
Procedure eWhen checking the soldered surfaces of
19234511 main P.C.B. and replacing the parts, do as
shown below.
3. Remove the rib.
4. Remove the main P.C.B. in the direction of arrow.
1. Remove the 4 screws (Q@~@).
Input/output terminal P.C.B.
Front panel
ass'y
Bottom board ass'y
4. Connect the G.N.D. terminal to the bottom board ass'y by
the lead wire.
§. Reinstall the front panel ass'y to the input/output terminal
P.C.B.
2. Remove the rib.
3. Remove the main P.C.B. in the direction of arrow.
a ee
SA-CH750
Removal of the Power IC and
14 Regulator Transistor
Procedure
1324-6
37311312514
1. Unsolder the power IC or regulator transistors.
2. Remove the 3 screws (@~@).
Regulator transistor
e When mounting the power IC or regulator transistor, apply
silicone compound (RFKX0002) to the rear side of power IC
or regulator transistors.
poe | Removal of the Fan Ass’y
Procedure
13511515
Fan ass'y
Fig.1 2. Insert a screwdriver at the root of the fan (shown in Fig. 2).
3. Remove the cap (shown in Fig.3).
4. Remove the motor from the fan case (shown in Fig. 4).
5. When mounting the motor, align the fan case projection with
the hole of the motor (shown in Fig.5).
1. Release the 3 claws (shown in Fig. 1).
@ Replacement of the Foot
1. Remove the 4 heat melted posts on the Bottom board ass'y
with a pair of nippers or similar tool.
2. To replace the foot (RKA0055-N) on the Bottom board ass'y ,
melt the 4 posts with a soldering iron.
Heat melted posts
pee ae
Foot
Bottom board ass'y ea
Foot
(RKAOO55-N)
2432