Sharp RT-31 User Manual

SHARP SERVICE MANUAL $1
OUTSTANDING RECEPTION THE WORLD OVER
ATM581 067DCK
Photograph of RT-31 H
Notice: You can make use of the item “DISASSEMBLY”,
regardless of the difference in appearance of the set,
whose photographs are all those of Model RT-31H
(not RT-31 for SEC.)
SPECIFICATIONS
Power source:
Power consumption:
Semi-conductors:
Dimensions: Width;
Height;
Depth;
Weight:
Tape:
Tape speed :
Wow & flutter:
Frequency response:
Normal tape;
(RT-31 H/HB)
Normal tape;
(RT-31)
AC 11 OV/22OV/24OV, 50160 Hz
(RT-31 H/HB)
AC 12OV, 50/60 Hz (RT-31)
12 wattes (RT-31 H/HB)
10 wattes (RT-31)
7 ICs (Integrated Circuits)
12 Transistors
9 Diodes
6 LEDs (Light Emitting Diodes)
430 mm (16-15116”)
1 15.5 mm (4-9/l 6”)
237 mm (9-5/l 6”)
3.9 kg (8.6 Ibs) (RT-31 H/HB)
3.7 kg (8.2 Ibs) (RT-31)
Philips standard compact cassette
tape
4.8 cm/set. ( l-7/8 ips.)
0.19% (DIN 45 500)
0.06% (W.R.M.S.) (RT-31 H/HB)
0.065% (W.R.M.S.) (RT-31)
40 - 12,500 Hz (DIN 45 500)
40-ll,OOOHz~3dB
30 - 14,000 Hz
40-12,000Hz+3dB
00
DOLBY SYSTEM @
Noise reduction system manufactured under license
from Dolby Laboratories Licensing Corporation.
“Dolby” and the double-D symbol are trademarks of
Dolby Laboratories Licensing Corporation.
RT-31 For SEC)
RT-31 H
(For SEEG, SUK, SCA and General)
RT-31 HB For SEW
In the interests of user-safety the set should be
restored to its original condition and only parts
identical to those specified by used.
MAXELL UDXLII tape;
(RT-31 H/HB)
40-14,000Hz(DIN45500)
40 - 13,000 Hz 2 3 dB
MAXELL UDXLII tape;
(RT-31)
30 - 15,000 Hz
40 - 13,009 Hz f 3 dB
TDK Metal tape; 40 - 16,000 Hz (DIN 45 500)
(RT-31 H/HB)
40 - 14,000 Hz f 3 dB
SONY Fe-Cr tape; 40 - 14,000 Hz (DIN 45 500)
(RT-31 H/HB)
40 - 13,000 Hz + 3 dB
S/N ratio (MAXELL UDXLII tape):
Dolby NR off;
56 dB
Dolby NR on; 66 dB (at over 5 kHz)
Input sensitivity and input impedance:
Microphones; 0.2 mV (6.8K ohms)
Line in;
50 mV (50K ohms)
DIN input;
0.2 mV (6.8K ohms) (RT-31 H/HB)
Output level and loaded impedance:
Headphones;
46 mV (“0” dB) , 8 ohms
Line out; 550 mV (“0” dB), 50K ohms
DIN output; 550 mV (“0” dB), 50K ohms
(RT-31 H/HB)
Specifications are subject to change without prior notice.
SHARP CORPORATION
SHARP ELECTRONICS CORPORATION

Sharp RT-31 Specifications

General

Brand	Sharp
Model	RT-31
Category	Cassette Player
Language	English

Summary

Disassembly Procedures

Removal of Cabinet

Steps for removing the main outer casing of the unit.

Removal of Bottom Plate

Procedure to detach the bottom panel of the unit.

Removal of Front Panel

Steps for detaching the front fascia and controls.

Removal of Mechanism Block

Instructions for removing the tape transport mechanism.

Mechanical Adjustment

Pinch Roller Pressure Adjustment

Adjusting the force applied by the pinch roller to the capstan.

Torque Check at Play, Fast Forward and Rewind Modes

Verifying tape tension and drive torque in various modes.

Tape Speed Adjustment

Calibrating the playback speed using a test tape and frequency counter.

Electrical Adjustment

Bias Current and Bias Oscillation Frequency Adjustment of Record Amplifier

Setting record amplifier bias frequency and current.

Erase Voltage Check

Verifying the voltage level for the erase head.

Record/Playback Head Azimuth Adjustment

Aligning the record/playback head for optimal phase.

Playback Frequency Characteristic Check

Measuring frequency response deviation using test tapes.

Playback Sensitivity Adjustment

Calibrating playback sensitivity across different tape types.

Record/Playback Sensitivity Adjustment

Adjusting record and playback levels for various tape formats.

Peak Level Display Meter Sensitivity Adjustment

Calibrating the sensitivity of the peak level indicator LEDs.

Dolby Noise Reduction Circuit Check

Verifying the function of the Dolby NR circuit.

Replacement Parts List

Integrated Circuits and Semiconductors

Lists ICs, transistors, diodes, LEDs, and Zener diodes.

Coils and Passive Components

Lists coils and other passive electrical components.