Technics SAG 76 Service Manual

Page 1

ORDER NO. MD960200201

Service Manilal

AV Control Stereo Receiver

I Specifications
I FM Tuner Section

Frequency range
Sensitivity
50 dB quieting sensitivity
MONO
STEREO
Total harmonic distortion

uri-

PRO-

57.9 - 107.9 MHz
11.2 dBf (2 uV, IHF 53)

18.3 dBf (4.5 LLV, iHF '53)
38.3 dBf (45 uv, IHF '53)

MONO 0.2%

STEREO 0.3%
SIN

MONO 75 dB

STEREO 70 d B
Frequency response 20 Hz - 15 kHz, +1 dB, -2 dB
Alternate channel selectivity 65 dB
Capture ratio 1 dB
image rejection at 98 MHz 44 dB
IF rejection at 98 MHz 80 dB
Spurious response rejection at 98 MHz 75 dB
AM suppression 50 dB
Stereo separation

1 kHz 40 dB

10 kHz 30 dB
Carrier leak

19 kHz -35 dB

38 kHz -50 dB
Antennaterminal(s) 75 Q (unbalanced)

I AM Tuner Section
Frequency range
Sensitivity

Selectivity

image rejection at 1000 kHz
IF rejection at 1000 kHz

530 - 1710 kHz
20 (N, 330 uV/m
55 dB

40 dB

60 dB

Technics®

Receiver
SA- G 76
L O G I C
Colour
(K) ........ Black'i'ype
Area
Suffixfor
Model No. Area C°'°""

(PP) U.S.A. and Canada (K)

System No. : S175PC-K, 82700P-M, SZ750P-K
(Refer to page a)

J. Manufactured under license from Dolby Laboratories
Licensing Corporation. Additionally licensed under one or
more of the following patents: U.S. numbers 3,632,886,
3,746,792 and 3,959,590; Canadian numbers 1,004,603 and
1,037,877.

"Dolby" and the double-D symbol are trademarks of Dolby
Laboratories Licensing Corporation.

I Video Section

Output voltage at 1 V input (unbalanced) 1:0.1 Vp-p
Maximum input voltage 1.3 Vp-p
lnputloutputimpedance 75 Q

I Amplifier Section
Rated minimum sine wave RMS power output

40 Hz - 20 kHz both channels driven

0.9% total harmonic distortion 110 W per channel (8 Q)
1 kHz continuous power output both channels driven

0.9% total harmonic distortion 1 15 W per chan nei (8 Q)
Total harmonic distortion

Rated power at 40 Hz - 20 kHz 0.9% (8 9)

Half power at 1 kHz 0.05% (8 9)
Power output at the Dolby Pro Logic operation

0.9% at 1 kHz,

Front 2 x 100 W (8 Q)

Center 100 W (8 Q)

Surround 100 W (8 Q)

(Surround speakers' total impedance)

SMPTE intermodulation distortion 0.9% (8 :2)
Dynamic headroom 2 dB (8 S2)
Low frequency damping factor, 30 (8 9)
Load impedance

Front 8 9

Center 8 Q

Surround 4 - B 9
Input sensitivity

PHONO 0.3 mV (3 mV, IHF 66)

CD, TAPE MONITOR, VCR 1. TVNCR 2
18 mV (200 mV, IHF '66)
Inputimpedance
PHONO 47 k9
CD, TAPE MONITOR, VCR 1, TVNCR 2 2 kn

© 1996 Matsushita Electronics (8) Pte. Ltd.
All rights reserved. Unauthorized copying and
distribution is a violation of law.

Page 2

SA-G76

information by anyone else could result in serious injury or death.

A WARNING
This se rvice info rrnation is designed for experienced repair technicians only and is not designed for use by the general public. it does not contain
warnings orcautions to advise non-technical individuals of potential dangers in attempting to service a product. Products powered by electricity should
be serviced or repai red only by experienced professional technicians. Any attempt to se rvice or repair the product or products dealt with in this service

SIN (IHF A)
PHONO
co, TAPE MONITOR, vcn 1, Wine 2
75 dB (35 dB, IHF 66)

70 dB (30 dB, IHF 66)

Frequency response
PHONO RIAA standard curve 10.8 dB
CD, TAPE MONITOR, VCR 1, TVNCR 2
10 HZ - 60 kHz, :3 dB
Tone controls

BASS 50 Hz, +10 dB to -10 dB

TREBLE 20 kHz, +10 dB to -10 dB
Super bass 30 Hz, +7 dB
I Contents Page
SAFETYPRECAUTIONS ................... 2
BEFORE REPAIR ANDADJUSTMENT. 2
PROTECTION CIRCUITRY ................ 2
LlNE-UPCOMPONENTS... 3
FRONT PANELCONTROLS. 3
OPERATION CHECKS& MAIN COMPONENT REPLACEMENT 4 ~ 7

FAN MOTOR TROU BLESHOOTI NG
TROUBLESHOOTING ..
TERMINAL FUNCTION 0

- Safety Precautions (This "Safety Precaution" is applied only In u. s. A.)

Before servicing, unplug the power cord to preventan electric shock.

waved

Insulation Resistance Test

Turn on the power switch.

PN.

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.

Alter servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc. metal
Before returning the serviced equipment to the customer, be sure to make the following insulation Pa"
resistance test to prevent the customerfrum being exposed to a shock hazard.

Measure the resistance value with ohmmeter between thejumper 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 5.2Mnto all exposed parts. ( Fig. 1 ) Equipment without

I General

Power consumptlon
Power supply
Dlmenslons (W x H x D)

270 W, 850 VA

AC 120 V, 60 HZ

430x 153x360 mm
(16'5/"x6'/32"x14'7")

Weight 9.5 kg (20.9 lb.)

Notes :
1. Specifications are subject to change without notice.
Weight and dimensions are approximate.
2. Total harmonic distortion is measured by the digital spectmm analyzer.

Page
PRINTEDCIRCUITBOARD. . 13 ~19
BLOCKDIAGRAM ............ . 20 ~ 23
WIRING CONNECTION DIAGRAM . 24
SCHEMATICDIAGRAM .................................................... 25 ~ 38
TERMINAL GUIDE OF le, TRANSISTORS AND DIODES. 39
CABINET PARTS LOCATION . 40

REPLACEMENT PARTS LIST.
PACKAGING...
RESISTORS&

Antenna }

terminal \3 I'

Exposed a

g Ohmmeter

Fig. 1
Resistance = 3M!) - 5.2M!)

Unplug the power cord and short the two prongs of the plug with a jumper wire.

antenna terminals should read approximately infinity to all exposed parts. ( Fig. 2 ) Vrnetal
Note : Some exposed parts may be isolated from the chassis by design. These will read infinity. 98"
4. lfthe measurement is outside the specified limits, there is a possibility of a shock hazard. The equipment F 2 Ohmmter
rg.

should be repaired and rechecked before it is returned to the customer.

I Before Repair and Adjustment

Resistance = Approx m

Disconnect AC power, discharge both Power Supply Capacitors (C703 to C706) through a 105), SW resistorto ground.
DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.

Current consumption at 120V, 60 Hz in NO SIGNAL mode should be 400 ~ 1000 mA.

I Protection Circuitry

The protection circuitry may have ope rated if either of the following
conditions are noticed:

' No sound is heard when the poweris turned on.

- Sound stops during a performance.
The function of this circuitry is to prevent circuitry damage if, forexample,
the positive and negative speaker connection wires are shorted", or if
speaker systems with an impedance lessthan the indicated rated impedance
of the amplifier are used.

If this occurs, follow the procedure outiines below:
1. Turn ol'lthe power.
2. Determine the cause of the problem and correct it.
3. Turn on the poweronce again afterone minute,

Note:
When the protection circuitry functions, the unit will not operate unless
the poweris first turned off and then on again.