Technics SUA 4 Mk2 Service Manual

Page 1

Service Manual

ORDER NO. SD8306252408 l

PRINTED CIRCUIT BOARDS .

LOCATION OF CONTROLS ..... BLOCK DIAGRAM ........

DISASSEMBLV INSTRUCTIONS. . . : . . . SCHEMATIc DIAGRAM . . . . . .
- . ADJUSTMENT PROCEDURE .......... . . . . . . . . . . e RESISTORS & CAPACITORS ......
Stereo DC Control Amplifier PRINTED CIRCUIT BOARDS WIRING REPLA CEMENT PARTS LIST . . . . . .
CONNECTION DIAGRAM ........... . . . . . . . 7~9 EXPLODED VIEWS. . . . ................... 23, 24

SU-A4MK2

[E],[EH],[EB],[EF].
lEK].[Ei].[XA]

I SAFETY PRECAUTIONS

Before servicing, unplug the power cord to prevent an electric shock,

When replacing parts, use only manufacturers 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 electric shock hazard.

U'Pri-

Areas

" [E] is available in Scandinavia and Switzerland.

*[EH] is available in Holland,

[EB] is available in Belgium.

'IEF] is available in France

'[EK] is available in United Kingdom.

*(Eil is available in Italy.

[XA] is available in Southeast Asia, Oceania, Africa, Middle Near
Eastand Central South America.

0 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 ohmmeter between the jumpered AC plug and each exposed metal cabinet part, such as
screwheads antenna, control shafts, handle brackets, etc. Equipment with antenna terminals should read between 3M9
and 5,2MQ to all exposed parts. (Fig. A) Equipment without antenna terminals should read approximately infinity to

Specificafions (Specifications are subject to change without notice for further improvement.)

(DIN 45 500)
I AMPLIFIER SECTION

Total harmonic distortion (2!! Hz~20 kHz)

PHONO MM 2.5 mV 0.006%
(0.001%, 2V output at vol. max,)
PHONO MC 250 uF 0.01%
(0,001%, 2V output at vol. max.)
TUNER, AUX, CD. VIDEO, TAPE 1. TAPE 2 0.006%

(0.001%, 2V output at vol. max.)
Input sensitivity and impedance

PHONO 1 MM 1 mV/47kQ

2.5 mV/47k0

PHONO 1 MC 70 yV/SOQ

250 yV/47UO

PHONO 2 MM 2.5 mV/47kn

TUNER 150 mV/47k0

AUX/CD/VIDEO 150 mV/47kn

TAPE 1, 2 150 mV/47kn
PHONO maximum Input voltage

MM 160 mV

MC 16 mV

S/N
PHONO MM 79 dB (92 dB, lHF, A)

MC 74 dB (82 dB, lHF. A)

TUNER, AUX/CD/VIDEO, TAPE 1, TAPE 2
100 dB (lHF. A: 106 08)

Frequency response

PHONO MM RIAA standard curve
10.15 dB (20 Hz~20 kHz)
PHONO MC RIAA standard curve

:02 dB (20 HZ~100 kHz)

TUNER, AUX/CD/VIDEO, TAPE 1, TAPE 2
DC~20 kHz (+0 dB, '01 dB)
DC~200 kHz (+0 dB, *3 dB)

all exposed parts. (Fig. B)
Note: Some exposed parts may be isolated from the chassis by design, These will read infinity.

Shelving tone

SUPER TREBLE (50 kHz) -10 d8~*10 dB
TREBLE (20 kHz) *5 dB~+5 dB
BASS (50 Hz) -5 dB~+5 dB
SUPER BASS (20 Hz) 0 de~+io dB Ame?
Turnover Irequency termmal
SUPER TREBLE 8 kHz
TREBLE 2 kHz
SUPER use (12 da/ocI) 75 Hz, 150 Hz Exposed Exposed
BASS 500 HZ metal metal
Subsonic lllter 20 Hz, '12 dB/oct. part part
High-cut filter 7 kHz. -6 dB/oct.
Loudness control (volume at -30 dB) 50 Hz. +7 :18 Ohmmeter Ohmmeter
Muting -20 dB
Output voltage and impedance . .
PRE OUT rated 2w2n _(th.A) (F'g' 3

max, 8V/20

150 mV/sooo Resistance = Approx 00

TAPE, 1, 2 REC OUT Resistance = 3M9-5.2 MQ

I GENERAL
4. If the measurement is outside the specified limits, there is a possibility of a shock hazard, The equipment should be

POWGWOnsumPlion 15W repaired and rechecked before it is returned to the customer.
Power supply AC 50 Hz/SO Hz. 110V/120V/220V/240V
Dimensions (WXHXD) 430 X 97 X 330 mm
(16-15/16 X 3-13/16><13)

Weight 8 kg
(17.6 lb.)

Note:
Total harmonic distortion is measured by the digital spectrum

analyzer (H.P. 3045 system),

Technics

Matsushita Electric Trading 00., Ltd.
R0. Box 288. Central Osaka Japan

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I LOCATION OF CONTROLS

- Input selector
A |
fiealpirghrgbwizdifbse1fi3r2/ off/ [tape 2/tape 1/phono/tuner/CD, aux, video]
phonoltuner/CD, aux, Video] Phone selector

DC [phone 2 MM-2.5mV/phono 1MM-lmVA2.5mV
' I t -I h l MC-70 V-250 V]
Operation se ec ors via tone A, one fit It
Power/stand by" indicator

Audio muting switch
[ l OdB, - -20dB]

Power switch-J n Volume control

Control
panel door
opener

Super-bass tone control Balance control

Super-bass turnover frequency Loudness switch I I. off, _ on]

selectorl I 150Hz, - 75Hz]
Bass tone control Mode selector I 1 stereo, :- mono]
Treble tone control
Super-treble tone control

Aux selector [CD/an x/video]

High-cut filter switch I 1 off, - 7kHz]

Subsonic filter switch [ 1 off, _ 20Hz]

. 2 (MM) Tuner terminals
Phono Input-i-1

terminals :1 Tapel
0 terminals
Aux input _
terminals
terminals
-- Power cord
Ground Voltage selector
terminals
Equalizer/Flat amplifier circuit
Recording-mode
selector switch
input selector
switch
Fuse circuit

Amorphous MC
transformer

Power transformer

Phono selector
switch circuit

Tone control circuit

Volume control
circuit

Operate selector circuit

Switch circuit

I DISASSEMBLY INSTRUCTIONS

0 How to remove the side, top and bottom
board.

1. Remove the 8 setscrews [Fig. 1: 0 ~91 of side

board and 10 setscrews [Fig. 1; @~ @1 of top fiziigoard
board. 6

2. Remove the 11 setscrews [Fig. 2: ® ~ @ 1 of (K\
bottom board. 69

on Front panel

Remove the screws by using the hexagonal rod wrench,
when the knob in the front panel has to removed.

0 How to remove the front panel
1. Remove the side and top boards.

2. Remove the 4 (red) setscrews [Fig. 2: Q) ~ 0 , Fig.3: ® ~ @] of
front panel, and carefully pull out the volume knob toward you.

Note) Remove the screw in the circle (broken line) when
the front panel has to be removed,

0 How to remove the lamp holder [Fig. 4]
1. Remove the bottom board and front panel.
2. Remove the lamp board and holder.

Rec selector /'

Input selector Q

Phono selector

Fig. 4

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