Technics STS 98 A Service Manual

Page 1

ORDER NO. A0890304OCI

A2
Tuner

ST-SQBA

Service Man

Gum Synthesizer
AMIFM Stereo Tuner

The main difference between the ST-SQBA and STvSQB (Service Manual No.

HA08803050C1) is the change of the tuner pack.

SPECIFICATIONS (IHF 78)

I FM TUNER SECTION

Frequency range 87.9 ~ 107.9 MHz (100 kHz step)

Sensitivity 10.8 dBi (0.95 pV/750,IHF 58)
50 dB quieting sensitivity

MONO 18.1 dBt(2.2 uV/750,lHF 58)

STEREO 38.1 dBi(22 uV/I'SQJHF 58)
Total harmonic distortion

MONO 0.2%

STEREO 0.3%
SIN

MONO 75 dB

STEREO 70 dB
Frequency response 20 Hz ~ 15 kHz. +0.5 dB ~ -1.5 dB
Alternate channel selectivity i400 kHz 65 dB
Stereo separation

1 kHz 40 dB

10 kHz 30 dB
Carrier leak

19 kHz -35 dB

38 kHz -50 dB

Antenna terminals 300 ohms (balanced)

75 ohms (unbalanced)

Color
(K) ........ Black Type

0833? Area Color
(M) U.S.A. (K)
(MC) Canada (K)
System
SC-S100 . SC-SZOO
SC-S3OO . 50-8400
80-3500

I AM TUNER SECTION

Frequency range
Sensitivity (SIN 20 dB)

530 kHz ~ 1720 kHz (10 kHz step)
20 uV.300 pV/m

Selectivity (i 10 kHz) 50 dB
Image rejection at 1000 kHz 40 dB
IF rejection at 1000 kHz 60 dB
I GENERAL

Output voltage 0.6V
Power consumption 9W

Power supply
Dimensions (W x H x D)

AC 120V,60 H2:

430 x 53 x 150 mm

(16-15/16 x 2-3/32" x 5-28/32)
Weight 1.5 kg (3.3 lb.)

Notes:

1.5peciiications are subject to change without notice.
Weight and dimensions are approximate.

2.Total harmonic distortion is measured by the digital
spectrum analyzer (HP. 3045 system).

Page Page
SAFETY PRECAUTION .......................................................... 2 CIRCUIT BOARDS AND WIRING
LOCATION OF CONTROLS ............................................... 2, 3 CONNECTION DIAGRAM ............................................... 9. 10
DISASSEMBLY INSTRUCTIONS ............................................ 3 TERM'NAL GU'DE 0E '0 S
TRANSISTORS AND DIODES ........................................... 10
MEASUREMENTS AND ADJUSTMENTS """""""""""""""""""" 4' 5 SCHEMATIC DIAGRAM .............................................. 11~13
DESCRIPTION OF Fl- PANEL ------------------------------------------------- 5 RESISTORS&CAPACITORS ................................................... 14,15
FUNCTION OF lC TERMINALS ..................................................... 6 REPLACEMENT PARTS LIST ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 15,15
BLOCK DIAGRAM .............................................................. 7. 8 EXPLODED VIEW ................................................................. 16
Matsushita Services Company Panasonic Hawaii, Inc. Panasonic Sales Company.
50 Meadowland Parkway, 99-859. Iwaiwa Street Division of Matsushits Electric

Technics

Secaucus. New Jersey 07094

PO. Box 774
Honolulu. Hawaii 96808-0774

of Puerto Rico, inc.

San Gabriel Industrial Park
65th lnlantry Ave. Km.9.5
Matsushits Electric Carolina. PR 00630
of Canada Limited

5770 Ambler Drive. Mississauga.

Ontario. L4W 2T3

Page 2

I SAFETY PRECAU'HON (This safety precaution" is applied only In U.S.A.)

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

2. When replacing parts, use only manufacturers recommended components for safety.

3. Check the condition of the power cord. Replace if wear or damage isevident.

4. After servicing, be sure to restore the lead dress, insulation barriers, insulation papers, shields, etc.

5. Before returning the serviced equipment to the customer, be sure to make the following insulation resistance test to
prevent the customer from being exposed to a shock hazard.

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 5.2MSZ to all exposed parts. (Fig. A) Equipment without antenna terminals should read approximately infinity to
all exposed parts. (Fig. 8)

Note: Some exposed parts may be isolated from the chassis by design. These will read infinity.

Antenna
terminal

Exposed Exposed
metal metal
p3 pan
Ohmmeter
(Fig.A)
Resistance = 3 MQ-5.2MQ Resistance = Approx 00

4. If the measurement is outside the specified limits, there is a possibility of a shock hazard. The equipment should be
repaired and rechecked before it is returned to the cusromer.

I LOCATION OF CONTROLS

OFront panel
II E E I! E E E!

'- 0 ' "I. . ..v. . I F. -.v" vi . ,
. .I; 3 g «r _ Is,- .2. *2: w ,1 :3.ng .:.2.

i Power switch (power) 8 Remote-control slgnal receptor
(remote sensor)

9 Tuning buttons (tuning)

2 FM stereo indicator (stereo)

3 Dlgltal frequency display

IO FM mode selector (FM mode)

4 Memory Indicator ( M )

ll Memory button (memory)

5 Quartz-lock indicator (quartz lock)

12 Band selectors (band)

6 Power indicator (standby)

13 Preset-tuning buttons (1 -0)
7 Channel display (24 channel random preset tuning)