Realistic sct 30 service manual

Page 1

E fiQEAL/Shq®

Service Mamas]

SOT-30
3 HEAD DUAL CAPSTAN

STEREO CASSETTE TAPE DECK
Catalog Number 14-603

CUSTOM MANUFACTURED FOR RADIO SHACK A DIVISION OF TANDY CORPORATION

Page 2

FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS DECK,
PLEASE REFER TO THE OWNER'S MANUAL.

CONTENTS

SPECIFICATIONS ................................................................................................................................................... 2
BLOCK DIAGRAM .............................

DOLBY NOISE REDUCTION SYSTEM

DOLBY FM ............ .
AUTO STOP MECHANISM ................................................................................................................................. 9
DISASSEMBLY ...................................................................................................................................................... I I
LUBRICATION ............................................................................................................................................... I4

ADJUSTMENT OF ELECTRICAL PARTS ..
ADJUSTMENT OF MECHANICAL PARTS

TROUBLESHOOTING
CIRCUIT BOARD DIAGRAM (TOP VIEW) ......................................................................................................... 29
CIRCUIT BOARD DIAGRAM (BOTTOM VIEW) ................................. .31

EXPLODED VIEW (CABINET) .
EXPLODED VIEW (MECHANISM). .34
SCHEMATIC DIAGRAM ....................................................................................................... SEPARATE SHEE1
REPLACEMENT PARTS (ELECTRICAL) ................................................................................................................. 35

SPECIFICATIONS
GENERAL SPECIFICATIONS
POWER SUPPLY .......................................................................................... AC 120V, 60 Hz (U.s.A., CANADA)
AC 220-240V, 50 HZ (EUROPE)
AC 240V, 50 Hz (U-K., AUSTRALIA)
AC 100V, 50/60 HZ (JAPAN)
POWER CONSUMPTION ........................................................................... 17W
RECORDING SYSTEM ................................................................................. AC bias, 105 kHz \
ERASING SYSTEM .................................................................................... AC erase, 105 kHZ
INPUT IMPEDANCE
MIC. ................................................................................................ 500-5K ohms
AUX IN ............................................................................................. 100K ohms
DIN ................................................................................................... 1.5K ohms
s 2 L

OUTPUT IMPEDANCE

PREAMP OUT ................................................... 10K ohms
DIN .................................................................. 20K ohms
HEADPHONE ..8 ohms

OUTPUT LEVEL ..O.55V (adjustable)

(DIN : 0.25V High, 0.1V Low)

TAPE ........................................................................... Cassette tape
TAPE SPEED ............................................................... 1-7/8 ips (4.75 cm/sec.) i2%
DIMENSIONS ............................................................ 5-11/16(H)>< 17-15/16(W)><10"(D)
(14.4 x 45.6 X 25.4 cm)
WEIGHT ......................................... 16 lbs. 8 oz. (7.5 kg)
PERFORMANCE SPECIFICATIONS
FREQUENCY RESPONSE Nominal Limit
SUPERTAPE ...................................................... 30-15000 Hz 40 Hz:gdB-12kHzt5 dB
CrOz / recI ...................................................... (SO-16,000 Hz 40 HzfigdB-Mkmfi: dB
SlGNAL-TO-NOISE RATIO
SUPERTAPE ...................................................... 55 dB (DOLBY NR IN) 45 dB
51 dB (DOLBY NR OUT) 40 dB
Cr02 / FeCr ...................................................... 57 dB (DOLBY NR IN) 49 dB
(CrOz. CClR weighted :61 dB)
53 dB (DOLBY NR OUT) 45 dB
ERASE RATIO ............................................................ 70 dB 60 dB
CROSS TALK ................ ..60 dB 55 dB
wow AND FLUTTER "0.12% R.M.s. 0.22%R.M.S.
(0.06% w.R.M.s.) (0.08% W.R.M.S.)
DISTORTION at o vu ................................................ 0.9% 3%
CHANNEL SEPARATION .......................................... 35 dB 27 dB
FAST FORWARD OR REWIND TIME (c-so) ............ IooSec. 125sec.
INPUT SENSITIVITY
MIC. .................................................................. -68 dB m (0.3mV) ~68 dB m :g dB
Aux IN ............................................................ -20 dB rn (BOmV) -20 dB m :g dB
.. ~68 dB m :3 dB
OUTPUT LEVEL (1 kHz OVU) ..... .o.55v 0.55Vir3 dB
HEADPHONE OUTPUT (TEST TAPE:
TEAC MTT-ISO) ......... 63mV 63mVir3 dB (an LOAD)
TAKE-UP TORQUE (PLAY) ....................................... sogr-cm 35~709r-cm
TAKE-UP TORQUE (FF & REW) ................................. QOgrecm 75~12OQr-cm

NOTE: Nominal Specs represent the design specs ; all units should be able to approximate these. Some will exceed and
some may drop slightly below these specs. Limit Specs represent the absolute worst condition which still might be

considered acceptable; in no case should a unit perform to less than within any Limit Spec.

_3_