Technics SU-V55A User manual

NO. HAD8704086C8
Service Manual
Stereo Integrated Amplifier Amplifier
SU-V55A
SPECIFICATIONS
(OIN 45 500)
AMPLIFIER SECTION
Color
(S) .... ....Silver Type
(K).... ....Black Type
Area
Color Area
(S)(K) (E) Continental Europe.
(S)(K) (Ei) Italy.
(S)(K) (EG).... F.R. Germany.
(S)(K) (EB).... Belgium.
(S)(K) (EK).... United Kingdom.
(S)(K) (EF) .... France.
(S)(K) (EH).... Holland.
(S)(K) (XL) .... Australia.
(S)(K) (XA).... Asia, Latin
America, Middle
Near East,Africa
and Oceania.
20 Hz ~20 kHz continuous power output
both channels driven 2 X 60 W(80)
1kH continuous power output
both channels driven 2x 100 W(40)
Total harmonic distortion
rated power at 20 Hz -20 kHz 0.002% (80)
rated power at 1kHz 0.005% (40)
0.0009% (80)
half power at 20 Hz -20 kHz 0.002% (80)
half power at 1kHz 0.002% (40)
0.0008% (80)
Intermodulation distortion
rated power at 250 Hz:8 kHz =4:1, 8Q 0.005%
rated power at 60 Hz:7 kHz =4:1,SMPTE,8Q 0.005%
Power bandwidth
both channels driven,-3dB 5Hz -60 kHz (80,0.03%)
Residual hum and noise 0.8 mV
Damping factor 30 (4O).60 (80)
Input sensitivity and impedance
PHONO MM 2.5mV/47 kO
PHONO MC 170 mV/220 0
TUNER,CD,AUX,TAPE 1/DA TAPE,
TAPE 2/EXT 150mV/22 kO
PHONO maximum input voltage (1 kHz,RMS)
MM 160 mV
MC 12 mV
S/N
rated power(4D)
PHONO MM 77 dB (83 dB:IHF,A)
PHONO MC 64 dB (65 dB:IHF,A)
TUNER,CD,AUX,
TAPE 1/DA TAPE,TAPE 2/EXT 91 dB (100 dB:IHF,A)
-26 db power (40)
PHONO MM 68 dB
PHONO MC 62 dB
TUNER,CD, AUX,
TAPE 1/DA TAPE,TAPE 2/EXT
50 mW power (40)
PHONO MM
PHONO MC
TUNER,CD,AUX,
TAPE 1/DA TAPE,TAPE 2/EXT
Frequency responce
PHONO
TUNER,CD,AUX,
TAPE 1/DA TAPE,TAPE 2/EXT
Tone controls
70 dB
62 dB
61 dB
62 dB
RIAA standard curve
±0.8dB(30Hz ~15 kHz)
5Hz ~120 kHz (-3dB)
+0, -0.2dB(20 Hz ~20 kHz)
BASS
TREBLE
Loudness control (volume at -30 dB)
Output voltage
TAPE 1,2 REC OUT
Channel balance, AUX 250 Hz ~6,300 Hz
Channel separation, AUX 1kHz
Headphones output level
and impedance
Load impedance
MAIN or REMOTE
MAIN and REMOTE
50 Hz, +10 dB ~-10 dB
20 kHz, +10dB ~-10 dB
50 Hz, -l-9dB
150 mV
±1 db
50dB
500 mV/330 O
4Q ~16C
80-160
GENERAL
Power consumption 490 W
Power supply
For United Kingdom and Australia AC 50 Hz/60 Hz,
240 V
For continental Europe AC 50 Hz/60 Hz,220 V
For others AC 50 Hz/60 Hz,
110V/127 V/220 V/240 V
Dimensions (W xHxD) 430 x126 x290 mm
(16-15/16" X4-31/32" X11-7/16")
Weight 7.5 kg (16.5 lb.)
Notes:
1. Specifications are subject to change without notice.
Weight and dimensions are approximate.
2.Total harmonic distortion is measured by the digital
spectrum analyzer (H.P. 3045 system).
Technics Matsushita Electric Trading Co., Ltd.
P.O. Box 288, Central Osaka Japan

•The power supply for this unit varies depending upon the areas. Also, the parts used for power supply are different.
So, refer to the circuit diagram and replacement parts list.
*[XA] area is provided with voltage selector and AC outlets.
*240V (5O/6OH 2)for Australia and United Kingdom.
*220V (50/60Hz) for Continental Europe.
*127V/1 10V/220V/240V (50/60Hz) for other [XA] area.
*Phono input capacitance is about lOOpF.
^Suggestions n
•If noise is very annoying while listening to an FM or AM
broadcast, switch OFF the video disc player, compact-disc
player and turntable.
•Switch OFF the video disc player power if noise is
excessive while listening to an audio tape, compact disc or
regular phono disc.
Notes;
•To record sounds from acompact disc, press the input
selector marked “CD”.
The compact-disc-direct switch is for listening only; it
cannot be used to select the compact disc as a recording
source.
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 aperformance.
The function 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.
BEFORE REPAIR AND ADJUSTMENT
(1 )Turn off the power supply. Using alOfi, 5W resistor, shortcircuit both ends of power supply capacitors (C705, C706,
8200 iiF) in order to discharge the voltage.
(2) Before turning on the power switch of the set .
A. Connect the voltage controller to the primary side.
B. Connect the AC ampere meter to the primary side or connect the DC voltage metar to the "±B" circuit of the
secondary side.
C. Turn the VR of ICQ (VR401 and VR402) to minimum (counterclockwise).
D. After setting the output to zero of the voltage contoller, turn on the power switch of the set.
And increase the output of voltage controller gradually.
Then, check carefully whether the current value of primary side become more than followings value or whether
the DC voltage of secondary side is increasing slowly.
E. If the value of current is increasing unusually or the DC voltage is not increasing, lower the output level of yoltage
contoller immediately.
F. Check the transistors of voltage amplifier and current amplifier IC501
.
G. After repairing, adjust the ICQ.
•The current value of the primary side at no signal. (Confirm the power supply voltage of each area and provided
voltage of the set.)
Power supply voltage
1
AC110V AC127V AC220V AC240V
Consumed current 50/60Hz 280 ~560mA 260 ~520mA 140 ~280mA 130- 260mA
-3-D

DISASSEMBLY INSTRUCTIONS
"ATTENTION SERVICER"
SOME CHASSIS COMPONENTS MAY HAVE SHARP EDGES.
BE CAREFUL WHEN DISASSEMBLING AND SERVICING.
Ref. No.
1
Procedure
1
Ref. No.
2
How to remove the cabinet
•Remove the 5screws.
How to remove the front panel
Ref. No.
3
Procedure
1-2 -a
How to remove the P.C.B.
1.Push the 9tabs (O~©)
2. Remove the tone and volume P.C.B.
3. Remove the 3screws (®~®).
4. Remove the LED P.C.B.
Tone control PC.B
0®:
5. Remove the 1screw (©).
6. Push the 2tabs (©, ©).
7. Remove the speakers/headphones P.C.B.
Speakers/Headphones PC.B
Rec Selector PC.B
LED PC.B
Volume PC.B

How to remove the power 1C.
Ref. No.
5
Procedure
1-*.4 -5 1,Unsolder the power 1C.
Power 1C
\\\
2. Remove the 2screws (O-0)•
3. Remove the 4washer (@~@).
<•When mounting the power 1C, apply
silicon thermal compound {SZZOLl
5
or equivalent) to the rear of the power
1C,
D

MEASUREMENTS AND ADJUSTMENTS
Control positions and equipment used.
•Volume knob 0(Minimum)
•Main speaker selector off
•Remote speaker selector off
•Speaker impedance switch .. . .
•DC electronic voltmeter (EVM)
8^2 ~16f2
IDLING (ICQ) ADJUSTMENT
1. Test equipment connection is shown in figure.
Connect the DC EVM. on both channels.)
2. Turn the ICQ control volume (VR401, VR402)
counter-clockwise.
3. Turn ON the set when it is cold, and 15 sec. later,
adjust VR401 and VR402 so that the voltage is
50mV Also, check that the voltage is 60 ~85mV
(standard: 80mV) after lapse of 10 —15 minutes.
(Below 85mV after lapse of 60 min.).
d) ®
QQIQS
*® d)'
Lch. Rch.
DC EVM
2SA1309
2SC3311 MA165, MA167
SVDS10VB20F
SVDSR1K2LF
MA29WA
MA4062M, MA4033M
MA4160M LN021315P
LN014314PH1
LN064316P

PRINTED CIRCUIT BOARDS AND WIRING CONNECTION DIAGRAM
ITAPE 2/EXT IITAPE I/DA TAPE |
{REC OUT) (PLAYBACK) (REC OUT) (PLAYBACK) (240V 50/60Hz^
(220V 50/60HZ)
Power tn
POWER AMP. /CURRENT DRIVE AMP./VOLTAGE CONTROL AMR/
MUTING/PROTECTION/POWER SUPPLY PC.B.
Resistors, Capacitors, Coils indicated by (C), (R) or (L) area
used only in the EG (F. R. Germany )area.
(PHONO) (TUNER) (AUX) (TAPE I/DA TAPE)
1REC SELECTOR |
PHONO 4AUX
2TUNER 5- TAPE2^1
3CD 6TAPE 1<2

10 11 12 13 14 15 16 ,17 18 I19
(XA) ONLY CEG3 ONLY
(240V 50/60HZ)
(220V 50/60HZ) (II0/I27/220/240V 50/60Hz) (220V 50/60HZ)
jPower tronsformer [Power transformer
AMPLrFIER OPERATION MONITOR
CURRENT
DRIVE IND. VOLTAGE
CONTROL INO.
POWER
(UNSWITCHED) (SWITCHED)
PHONES JACK/
SPEAKER SELECTOR VOLTAGE SELECTOR
(CD DIRECT IND.)
(PHONO IND.)
LED INDICATOR P.C.B.
(TUNER IND.) (TAPE 2/EXT INO.) (TAPE 1/OA TAPE IND.)
VOLUME
PHONO EQUALIZER/TONE CONTROL/
VOLTAGE CONTROL AMP P.C.B.
PHONO
LOUDNESS
PHONO
SELECTOR
BALANCE

11 12

11II /11.1.11 nrr fIf-rt ,m t.i
PRINTED CIRCUIT BOARDS AND WIRING CONNECTION DIAGRAM
(REC OUT) (PLAYBACK) (REC OUT) (PLAYBACK) (240V 50/60HZ)
(220V 50/60H2)
Power trai
POWER AMP. /CURRENT DRIVE AMP. /VOLTAGE CONTROL AMP/
MUTING/PROTECTION/POWER SUPPLY PC.B.
Resistors, Capacitors, Coils indicated by (C), (R) or (L) area
used only in the EG (F. R. Germany )area.
PHONO
1PHONO 4AUX
2
TUNER 5TAPE 2^1
3CD 6TAPE Ie2
(PHONO) (TUNER) (AUX) (TAPE l/OA TAPE)

{II0/I27/220/240V 50/60HZ)
POWER
VOLTAGE SELECTOR
PHONO
LOUDNESS
BALANCE
IPower ffqnsform^
IPower transformer^
(CD DIRECT IND.)
|(S8» LJ
LEGj ONLY
(220V 50/60HZ)
(AUX IND.) (TAPE 2/EXT IND.) (TAPE I/DA TAPE IND.)
(PHONO IND.)
Led indicator rc.b.
(TUNER IND.)
AMPLIFIER OPERATION MONITOR
/CURRENT \/ VOLTAGE N
VdRIVE IND.KcONTROL IND./
PHONO EQUALIZER/TONE CONTROL/
VOLTAGE CONTROL AMP. P.C.B.
(XA) ONLY
(UNSWITCHED)
'
1AC OUTLET
PHONO
SELECTOR
PHONES JACK/
SPEAKER SELECTOR

Spea ker termina
I
For F.R. Germany [EG]
SCHEMATIC DIAGRAM
(This schematic diagram may be modified at any time
with the development of new technology.)
Note:
1. SI-1 ~S1-4: Input selector switch in "phono" position.
SI-1: phono SI -2: tuner SI -3: CD
SI-4: aux SI-5: Tape 2/ext SI-6: Tape 1/DA tape
2. S3-1,S3-2; Recording selector in "CD" position.
3. S4: Phono selector in "MM" position.
(«MM, MC)
4. S5: CD direct switch in "off" position.
(Moff, “on)
5. S6: Loudness switch in "off" position.
(Moff, on)
6. S8: Tone control switch in "defeat" position.
(.defeat, on)
7. S9-1: Main speaker switch in "on" position.
(Aoff, on)
8. S9-2; Remote speaker switch in "off” position.
(A off. —•on)
9. S11: Power switch in "on" position.
(Aoff, -“on)
10. S701 :(For [XAl area only): Voltage selector switch in "110V" position.
(127 V110V*- 220 V«-- 240 V)
11. Indicated voltage values are the standard values for the unit measured by the DC electronic
circuit tester (high-impedance) with the chassis taken as standard. Therefore, there may
exist some errors in the voltage values, depending on the internal impedance of the DC
circuit tester.
5>a?:i5ss!5|» Phono signal (Lch)
Positive voltage lines ————Negative voltage lines.
12. Important safety notice:
Components identified by Amark have special characteristics important for
safety. When replacing any of these components, use only manufacturer's
specified parts.
For other areas CX A] For F.R Germany [EG]
-15 -

REPLACEMENT PARTS LIST
/Class AA voltage control omplifier
Notes:* Important safety notice:
Components identified by Amark have special charac-
teristics important for safety. When replacing any of
these components use only manufacturer's specified
parts.
*Bracketed indications in Ref. No. columns specify the
area.
Parts without these indications can be used for all areas.
Numbering System of Resistor
Example
ERD 25 FJ102
Type Wattage Shape Tolerance Value
ERX 2AN J471
Type Wattage Shape Tolerance Value
47x10' (ohm)
Numbering System of Capacitor
Example
ECKD 1H 102 ZF
Type Voltage Value Tolerance Peculiarity
ECEA 50 M330
Type Voltage Peculiarity Value
(33x10° microfarad)
Resistor Type Wattage Tolerance
ERD Carbon 10 :1/8W J:±5%
ERG Metal Oxide 12:1 /2W F:±1%
ERX Metal Film 25 :1/4W G:±2%
ERQ
ERDTJ L
EROr.’; K
ERC
Fuse Type Metal
Carbon (chip)
Metal Film (chip)
Solid
lA :1W
18 :1/8W
S2 :1/4W
SI :1/2W
2F :1/4W
50 :1/2W
2A :2W
K:±10%
Capacitor Type Voltage Tolerance
ECE Electrolytic OJ :6.3V C:±0.25pF
ECCD Ceramic 1A :10V J:±5%
ECKD Ceramic 1C :16V K:±10%
ECQM Polyester 1E:25V Z.+80%
1H:50V -20%
ECQP Polyproylene IV: 35V P:+100%
50 :50V -0%
ECG Ceramic 05 :50V M:±20%
ECEADDON: Non Polar 2H :500V
Electrolytic 2A: 100V D:±0.5pF
QCUO Ceramic (Chip Type) 1:100V G:±2%
ECUX Ceramic (Chip Type) KC: 400V AC
ECF Semiconductor KC: 125VAC
(UL)
1J :63V
EECW Liquid electrolyte
double layer capcitor
Ref No. Part No. Part Code
RESISTORS
R101.RI02 ERDS2TJ102 001 152 2346 4
(EGI
R103, R104 EROS2TJ102 001 152 2346 4
(EG)
R106. RI06 ERDS2TJ274 001 152 2437 2
RI07. R108 ERDS2TJ22I 001 152 2431 8
R109. R110 ERDS2TJ220 001 152 2430 9
R113. R1I4 ERDS2TJ563 001 152 2446 1
RIIT, RU8 ERDS2TJ151 001 152 2426 5
RI19. R120 ERDS2TJ100 001 152 2420 1
R123. R124 ERDS2TJ151 001 152 2426 5
R125. RI26 ERDS2TJ682 001 152 2365 1
R127. R128 ERDS2TJ823 001 162 2456 9
RI29. RI30 ERDS2TJ334 001 152 2438 I
R131.R132 ERDS2TJ561 001 152 2364 2
R201. R202 ERDS2TJ102 001152 2346 4
(EGI
R203, R204 ERDS2TJ102 001152 2346 4
(EG)
R205. R206 ERDS2TJ102 001 152 2346 4
(EG)
mi. R208 ERDS2TJ102 001 152 2346 4
(EG)
R209. R210 ERDS2TJ102 001 152 2346 4
(EG)
R211.R212 ERDS2TJ473 001 152 2363 3
R213. R214 ERDS2TJ183 001 152 2429 2
R2I9. R220 FSR25TJ272T2
R301. R302 FSR2STJ561T2
R303. R304 EROS2TJ823 001 152 2456 9
R305. R306 ERDS2TJ224 001 152 2433 6
R307. R308 ERDS2JJ392 001 152 2439 0
R3Q9. R3I0 ERDS2TJ223 001 152 2432 7
R311.R312 EROS2TJ102 001 152 2346 4
R313, R314 ERDS2TJ562 001 152 2445 2
R315. R316 FSR2STJ392T2
R317. R318 FSR2STJ223T2
R3I9, R320 EROS2TJ183 001 152 2429 2
R401. R402 ERDS2TJ122 001 152 2423 8
R403. R404 EROS2TJ823 001 152 2466 9
R406. R406 FSR25TJ272T2
Ref. No Part No. Part Code
R407. R408 FSR25TJ823T2
R409, R410 EROS2TJ561 OOl 152 2364 2
R41I. R412 AERD25FJ470 001 152 0000 7
R415. R416 ERDS2TJ182 001 152 2352 6
R417. R418 EROS2TJ391 001 152 2360 6
R419. R420 AERD25FJ101 001 152 0214 3
R421,H422 EROS2TJ223 001 152 2432 7
R423. R424 ERD25FJ821 OOl 152 0354 2
R425. R426 EROS2TJ223 OOl 152 2432 7
R427, R428 Era325FJ101 001 1520214 3
R429. R430 ER025FJ2R2 001 152 0251 8
R431. R432 ERD25FJ2R2 001 152 0251 8
R433. R434 ERD25FJ101 001 152 0214 3
R435 ERDS2TJ103 001 152 2347 3
R436 AERD25FJ470 OOl 152 0309 7
R437 EROS2TJ473 001 152 2363 3
R438. R439 AERD25EJ6R8 001 152 0335 5
R501, R502 ER0S2TKF4220 001 151 5927 2
R506.R506 ERDS2TJ101 001 152 2421 0
R607. R508 ERDS2TJ101 001 152 2421 0
R509. R510 AERD25FJ271 001 152 0272 3
R511.R512 EROS2TJ271 001 152 2435 4
R513. R514 EROS1FJ100 001 152 2612 5
R515. R516 ERD25FJ100 001 152 0213 4
R517. R518 ERDS2TJ472 001 152 2362 4
R519, R520 ERDS2TJ1S3 001 152 2351 7
R523. R524 ERG2SJ331 001 151 3570 9
R601 ERDS2TJ391 001 152 2360 6
R602 ERDS2TJ331 001 152 23562
R604 ERDS2TJ471 001 152 2361 5
R605 ERDS2TJ331 OOl 152 2356 2
R607.R608 EROS2TJ473 001 152 2363 3
R609 EROS2TJ153 001 152 2351 7
R610 ERDS2TJ124 001 152 2425 6
R611 ERDS2TJ472 001 152 2362 4
R612 Ef^J821 OOl 151 4940 9
R613 ERDS1FJ180 001 152 26205
R614 EROS2TJ183 001 152 2429 2
R701.R702 ERDS2TJ153 001 152 2351 7
R703. R704 AERD25FJ821 001 152 03542
R705 ERDS2TJ122 OOl 152 2423 8
R707. R708 ERDS1FJ822 001 152 5897 6
Ref. No. Part No. Part Code
CAPACITORS
Cl A
(XA)
ECKDKC103PF2 001 103 3734 7
Cl
(E.ECEF)
(EH.EB.EI)
(XL)
ECKWNS103ZVS 001 103 9317 6
C108
(EG)
ECKD1H102KB 001 1031414 8
C108
(E. EK, EF)
(EK EB.EI
)
(XL.XA)
ECQM1H103JZ 001 106 0667 8
C104
(EG)
ECKD1H102KB 001 103 1414 8
C104
(E. EK. EF)
(EH,EB.EI)
(XL.XA)
ECOMIHIOSJZ 001 106 0667 8
C105.C106
(E. EK.EF)
(EH.EB.EI)
(XL.XA)
ECCD1H181K 001 103 0466 0
C107. C108 ECEA0JU222 001 120 3161 5
C109.C110
(EG)
ECKD1H471KB 001 103 1551 0
C111.C112 ECQM1H122JZ 001 106 0683 8
ciiaciH ECOM1H103JZ 001 106 0667 8
Cl 15. Cl 16 ECQM1H393JZ 001 106 0794 2
Cl 17. Cl 18 ECEA1HN0101S 001 120 0354 0
C119.C120 ECQM1H472JZ 001 106 0801 0
C121.C122 ECKD1H103PF 001 103 1449 7
CI23. C124 ECEA1HPS3R3 001 120 6064 3
C203.C204
(EG)
ECCD1H101K 001 103 0341 2
C205.C206
(EG)
ECCD1H101K 001 103 0341 2
C207.C208
(EG)
ECCD1H101K 001 103 0841 2
C209.C210
(EG)
ECCD1H101K 001 103 0341 2
C211.C212 ECCD1H101K 001 103 0341 2
17 -18 -