Technics SA-EH790E User manual

ORDERNO.AD0303004C2
Tuner/Amplifier
SA-EH790E / SA-EH790EB / SA-EH790EG / SA-EH790EP
Colour
(S)...................Silver Type
System: SC-EH790
Because of unique interconnecting cables, when a
compact requires service, send or bring inthe entire
system.
SPECIFICATIONS
Specification
1

Amplifier section
Power output (L/R bothchannel driven)
StereoMode
DIN 1kHz THD 1%/6 (High) 2×25 W
100 Hz THD 1%/8 (Low) 2×45 W
RMS 1kHz THD 10%/6 (High) 2×35 W
100 Hz THD 10%/8 (Low) 2×65 W
PRO LOGIC mode
DIN FRONT
1kHz THD 1%/6 (High) 2×25 W
100 Hz THD 1%/8 (Low) 2×45 W
SURROUND 1kHz THD 1%/8 2×30 W
CENTER 1kHz THD 1%/8 60 W
RMS FRONT
1kHz THD 10%/6 (High) 2×35 W
100 Hz THD 10%/8 (Low) 2×65 W
SURROUND 1kHz THD 10%/8 2×40 W
CENTER 1kHz THD 10%/8 80 W
PMPO 1kHz/High 6 , Low8 ,
CENT. 8 , SURR. 8 3000 W
Total harmonic
distortion
Ratedpower at 1kHz 1%(6 )
Half power at 1kHz 0.1%(6 )
Loadimpedance
FRONT(High) 6
FRONT(Low) 8
SURROUND 8
CENTER 8
DIGITALS. WOOFER
Center frequency 60 Hz
LEVEL(VOL-20 db) MID +3db
MAX +6db
FM tuner section
Frequencyrange 87.50—108.00 MHz
(0.05 MHz steps)
Sensitivity 1.8V (IHFusable)
S/N 26 db 1.5V
S/N
MONO 70 db (75 db, IHF)
Antennaterminal(s) 75 (unbalanced)
AM tuner section
Frequencyrange 522—1629 kHz (9kHz steps)
520—1630 (10 kHz steps)
Sensitivity(S/N 20 db) 500 V/m
Timer section
Clock Quartz-lock type
Function Playtimer (1time, daily),
Rec timer (1time, daily)
2

Sleep(120 min, 30 min
intervals)
Setting intervals(Play/Rec) 1 minute—23 hours 59 minutes
(1minintervals)
General
Power supply
(For(E) ,(EG),(EP)areas) AC 230V 50Hz
(For(EB) area) AC 230—240V 50Hz
Power consumption 190 W
Standby 0.5W
Dimensions(W×H×D) 293×118.5×345 mm
Mass 5.2kg
Nots 1.Design and specificationsare subject to
changewithout notice.
2.Dimensionsand mass are approximate.
3.Total harmonicdistortion ismeasuredbythe
digital spectrumanalyzer.
System/SC-EH790
Sound processor: SH-EH790, CD changer: SL-
EH790, Tuner/ Amplifier: SA-EH790 , Cassette
Deck: RS-DV290, Speakers: Front*(SB-DV290),
Center* (SB-PC95),Surround*(SB-PS95)(*Made
inMAES.)
2003 Matsushita ElectricIndustrial Co., Ltd. All rights reserved.
Unauthorized copying and distribution isaviolation of law.
1. Before Repairs
1. Turn off the power supply. Using a10 , 10 Wresistor, connect
both ends of power supplycapacitors (C701, C703 and C702,
C704) inorder to discharge the voltage.
2. Before turning the power supplyon, after completion of repair,
slowlyapplythe primaryvoltage byusing apower supplyvoltage
controller to make sure that the consumed current at 50 HzinNO
SIGNALmode shouldbe shownbelow with respecttosupply
voltage 230/240 V.
3

Powersupply
voltage AC 230 V AC 240 V
Consumedcurrent
50 Hz 100 - 350 mA
2. Protection Circuitry
The protection circuitrymayhave operatedif eitherof the following conditions is noticed:
-Nosound isheard when the power isswitched ON.
-Sound stops during aperformance.
The functions of this circuitryis toprevent circuitrydamage if, forexample, the positive and
negative speakerconnection wires are shorted, orif speakersystems withanimpedance less
thanthe indicatedratedimpedance of this unit are used.
If this occurs, followthe procedures outlinedbelow.
1. Switch OFF the power.
2. Determine the cause of the problem and correct it.
3. Switch ONthe power once again.
Note:
Whenthe protection circuitryfunctions, the unit will not operate unless the poweris first
switchedOFF and thenON again.
3. Accessories
-AC mains lead for (E),(EG)and (EP) areas
(RJA0019-2X)....................1pc.
-AC mains lead for (EB)area
(RJA0053-3X)....................1pc.
4

-Remote control
(EUR7702270)....................1pc.
-Remote control batteries
(R6/LR6,”AA”,UM-3)....................1pc.
Note: These are available on sales route.
-FM indoor antenna
(RSA0007)....................1pc.
-AMloop antenna set
(RSA0022-L)....................1pc.
-Speaker leads
5

(REE1234-1)....................2pc.
(Red/Black)
(REE1233-1)....................2pc.
(Gray/Blue)
-Antenna plug adaptor for (EB)area
(SJP9009)....................1pc.
4. Caution for AC Mains Lead
6

5. Location of Controls
6. Operation Checks and Component Replacement /
Procedures
-Thissection describes procedures for checking the operation of
the major printed circuitboards and replacing the main
components.
-For reassemblyafter operation checks or replacement, reverse the
respective procedures. Special reassemblyprocedures are
7

described onlywhen required.
6.1. Checking for the AC INP.C.B.
-Check the AC INP.C.B. as shownbelow.
6.2. Checking for the operation P.C.B.
-Follow the (Step 1) -(Step 3) of item 6.1.
8

-Check the operation P.C.B. as shownbelow.
6.3. Checking for the mainP.C.B.
-Follow the (Step 1) -(Step 3) of item 6.1.
9

10

-Check the mainP.C.B. as shownbelow.
6.4. Replacement for the regulator transistor
-Follow the (Step 1) -(Step 3) of item 6.1.
11

6.5. Replacement for the power IC
-Follow the (Step 1) -(Step 3) of item 6.1.
-Follow the (Step 1) -(Step 6) of item 6.2.
-Follow the (Step 1) -(Step 10) of item 6.3.
7. To Supply Power Source
This unit is designedtooperate on powersuppliedfromsystemconnected. / Forsystem
connection, referto Fig. 7-1.
Fig. 7-1.
12

Whenthe unit has totest and service alone, use the following method tosupplypowersource.
1. Short the section between W902APin3and C740 (-) (GND). (Refer
to Fig. 7-2. )
2. Connect thisunitto an AC power supplycord. / (Thisunitcome to
stand-bymode.)
3. Turn the unitON.
Fig. 7-2.
Notes:
Use onlythis method whenchecking the voltage etc.. / Incase of checking the operations, use
the systemconnections tosupplypowersource.
8. Self-Diagnostic Function
This unit is equippedwitha self-diagnostic function which, inthe event of a malfunction,
13

automaticallydisplays a code indicating the nature of the malfunction.
Use this self-diagnostic function whenservicing the unit.
8.1. To displaythe malfunction code
U70 CD:/ U70 DECK:
Automaticallydisplayson the tuner/amplifier when amalfunction
occurs. Refer to Fig. 8-1.
F61:
Automaticallydisplayson the tuner/amplifier when amalfunction
occurs. Refer to Fig. 8-1. Fig. 8-1.
8.2. To return to the normal display
1. For U70 CD/U70 DECK
-Press an anyoperation button on the tuner/amplifier.
-To re-displaythe code, switch the power off (POWER
STANDBYbutton), and then switch power back on again.
2. For F61
-IfF61 isdisplayed, the power will automaticallybe switched
off and the standbyindicator will light up.
-F61 will be displayed for 3seconds, and then the clock will be
displayed.
14

-To re-displaythe code, switch the power on. F61 will be re-
displayed, and then after 3seconds the clock will be displayed
and the power will automaticallyswitch off.
8.3. Displaycontents
8.3.1. U70 CD/U70 DECK / (displayed automatically)
-Problem or condition
Abus-line communications error has occurred as aresultof the
flat cables being inserted incorrectly, thus preventing the system
from operating.
-IfU70 isdisplayed on the tuner/amplifier, the tape deck or CD
Changer cannot be operated byremote control.
-Correction Procedure
1. To check for correct insertion of flat cables.
-Insert each connectors until you hear aclick.
-Insert the flat cables at the back of the unitinthe order
indicated. Refer to Fig. 8-2.
Make sure the white side of the cables ison your right side.
Refer to Fig. 8-3. Fig. 8-2.
Fig. 8-3.
2. Breakage of flat cables. (Check and replace.)
3. Ifthe problem isnot corrected byitems 1and 2above, this
indicates afaultyIC.
SA-EH790:
IC901 (C2BBFD000404)
15

SL-EH790:
IC451 (C2BBGF000433)
RS-DV290:
IC701 (M38503M2406F)
Check these ICsand replace.
8.3.2. F61
-Problem or condition
When the power switch isswitched on, itautomaticallyswitches
back off, making itimpossibleto switch power on.
-Correction procedure
FaultyTuner/Amplifier (SA-EH790) output IC(IC601). (When aDC
voltage isapplied to speaker terminals.)
9. Schematic Diagram Notes
-Thisschematicdiagram maybe modified at anytime with the
development of new technology.
Notes:
S901:
Power standby/on switch ( )
S902:
Clock/timer switch (CLOCK/TIMER)
S903:
Demo switch ( DEMO)
S904:
Playtimer/record timer switch / ( PLAY/ REC)
S905:
FM mode switch / (FM AUTO/MONO)
S906:
Tuning mode switch / (TUNING MODE)
S907:
Set switch (SET)
S908:
Source input switch / (INPUTSELECTOR)
16

S909:
6ch discrete input switch / (6 CH DISCRETE INIPUT)
S910:
Tuning downswitch (TUNING, )
S911:
Tuning up switch (TUNING, )
S912:
Tuner/band switch (TUNER/BAND)
S913:
Digital super woofer switch / (DIGITALS.WOOFER)
S914:
RDSdisplaymode PS switch / (RDSDISP MODE-PS)
S915:
RDSdisplaymode PTY switch / (RDSDISP MODE-PTY)
VR901:
Volume control VR(VOLUME)
-Indicated voltage values are the standard values for the unit
measured bythe DC electroniccircuittester (high-impedance)
with the chassistaken as standard. Therefore, there mayexist
some errors inthe voltage values, depending on
theinternalimpedance of the DC circuittester.
Nomark
:Power ON(FM or AM)
-Important safetynotice:
Components identified bymark have special characteristics
important for safety.
Furthermore, special parts which have purposes of fire-retardant
(resistors), high-qualitysound (capacitors), low-noise (resistors),
etc. are used.
When replacing anyof components, be sure to use only
manufacturer´s specified parts showninthe parts list.
-The supplypart number isdescribed alone inthe replacement
17

parts list.
-Voltage and signal line
:Positive voltage line
:Negative voltage line
:Audiosignal line
:Tuner signal line
Caution!
ICand LSI are sensitive to staticelectricity.
Secondarytroublecan be prevented bytaking care during repair.
Cover the parts boxes made of plastics with aluminum foil.
Ground the soldering iron.
Put aconductive mat on the work table.
Donot touch the legs of ICor LSI with the fingers directly.
10. Schematic Diagram
11. Printed Circuit Board Diagram
12. Type Illustration of ICs, Transistors and Diodes
13. Wiring Connection Diagram
14. Block Diagram
15. Terminal Function of ICs
15.1. IC901 (C2BBFD000404): / System Control/FL Drive
18

Pin
No.Terminal
Name I/O Function
1CHECK I Clock check signal input
2 LC72 DO O PLL data signal output fortuner
unit (Z120)
3LC72 CE O Chipenable signal output for
tunerunit (Z120)
4LC72 DI/
ST I IFcount data/stereodetect signal input fromtunerunit
(Z120)
5LC72 CK O Clock signal output fortuner
unit (Z120)
6ST/AV. /
6CH O Signal select output
7NC - Not used, open
8
9 SEL
TUNER - Not used, open
10 SEL/
TUNER - Not used, connectedtoGND
11 AC IN I Powerfailure detect signal input
12 RESET I Reset signal input
13 X IN I Oscillatorconnectedterminal
(32.7 kHz)
14 X OUT O
15 VSS - GND terminal
16 XC IN I Oscillatorconnectedterminal (6
MHz)
17 XC OUT O
18 VDD 1 I Powersupplyterminal
19 KEY TU I Operation keysignal input
20 KEY
KARAOKE I Operation keysignal input
21 SH REQ I Request signal input from
Sound Processor
22 NC(GND) - Not used, connectedtoGND
23 VR JOGB I Volume control signal input
24 VR JOGA
25 MIC DET I Microphone connecting detect
signal input
(Not used, connectedtoVDD )
26 HP SW I Headphone connecting detect
signal input
27 RDS CLK I RDS clock signal input
28 RDS
DATA IRDS data signal input
29 REMO /
CON I Remote control signal input
19

Pin
No.Terminal
Name I/O Function
30
|
37
8G
|
1G
O Gridsignal output
38
|
45
P1
|
P8
O Segment signal output
46 VDD 3 I Powersupplyterminal
47
|
50
P9
|
P12
O Segment signal output
51 -VP I Powersupplyterminal
(Negative)
52
|
71
P13
|
P32
O Segment signal output
72 VDD 4 I Powersupplyterminal
73
|
78
P33
|
P38
O Segment signal output
79 REGIN0 - Not used, connectedtoGND
80 REGIN1
81 STANDBY OLED (STANDBY) drive signal
output
82 TIMER O LED (TIMER) drive signal output
83 S.W.LED O LED (DIGITALS.WOOFER)
drive signal output
84 LOUNGE - LED (LOUNGE) drive signal
output
(Not used, connectedtoGND)
85 CHORUS - LED (CHORUS) drive signal
output
(Not used, connectedtoVDD )
86 MUTE O Muting signal output
87 NC - Not used, open
88 POWER O Powercontrol signal output
89 VSS 2 - GND terminal
90 VDD 2 I Powersupplyterminal
91 MUTE2 O Muting signal output
92 NC - Not used, open
20