Technics RS-M250 - Service Manual

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Service Manual
Microprocessor-Controlled Stereo Cassette Deck
with Electronic Digital Tape Counter
OO [covsy system
RS-M250 MECHANISM SERIES
Specifications
Track system: 4-track 2-channel stereo recording and playback
Tape speed: 4.8cm/s
Wow and flutter: 0.04% (WRMS), 0.13% (DIN)
Frequency response: Metal tape; 20— 20,000 Hz
30— 18,000 Hz (DIN)
30—17,000Hz +3dB
CrO2/Fe-Cr tape; 20 — 18,000 Hz
30— 18,000 Hz (DIN)
30—16,000Hz +3dB
Normal tape; 20—17,000Hz
30— 16,000 Hz (DIN)
30—15,000Hz +3dB
Signal-to-noise ratio; Dolby NR in; 67 dB (above 5 kHz)
Dolby NR out; 57 dB (Signal level = max. record-
ing level, Fe-Cr/CrO2 type tape)
Fast forward and
rewind time: Approx. 80 seconds with C-60 cassette tape .
Inputs: MIC; sensitivity 0.25 mV, input impedance 50kQ
applicable microphone impedance 4002—10 kQ
LINE: sensitivity 60 mV, input impedance 47kQ
Outputs:
Rec/pb connection:
Bias frequency :
Motor:
Heads:
Power requirement:
Power consumption:
Remote:
Dimensions:
Weight:
Specifications are subject to change without notice.
* ‘Dolby’ and the double-D symbol are trademarks of Dolby Laboratories.
Technics
Cassette Deck
RS-M250
eae ee
Black Face
This is the Service Manual for the
following areas.
For all European areas
except United Kingdom.
For United Kingdom.
LINE; output level 700 mV, output impedance 3 kQ
or less, load impedance 22kQ over
HEADPHONE ; output level 85 mV (at 8Q), load
impedance 8— 1252
5 pin DIN type;
input sensitivity 0.25 mV, input impedance 6.8 kQ
output level 700 mV, output impedance 4.7kQ
85 kHz
2-motor system;
1-Electrical DC governor motor, 1-DC motor
2-head system;
SX head for record/playback
Ferrite double-gap head for erasure
AC; 110/125/220/240 V, 50-60 Hz
20W
For PLAY/REC/FF/REW/PAUSE /REC-MUTE/
STOP with optional remote control RP-9645
43.0cm(W) X 11.9cem(H) x 29.3cm(D)
5.3kg
Matsushita Electric Trading Co., Ltd.
P.O. Box 288, Central Osaka Japan.

Technics RS-M250 Specifications

General

Track System	4-Track, 2-Channel Stereo
Tape Speed	4.8 cm/s
Tape Type	Normal, CrO2, Metal
Wow and Flutter	0.07% WRMS
Type	Stereo Cassette Deck
Motor	DC motor
Output	Line Out
Dimensions (W x H x D)	430 x 119 x 244mm
Power Supply	220V, 50Hz

Summary

Specifications

Measurement and Adjustment Methods

Measurement and Adjustment Procedures

Head Azimuth Adjustment

Procedure for aligning the record/playback head azimuth for optimal signal.

Tape Speed Accuracy

Method to measure and adjust tape speed accuracy to specified standard.

Playback Frequency Response

Steps to measure frequency response using test tape and VTVM/oscilloscope.

Measurement and Adjustment Procedures - Part 2

Playback Gain

Procedure to measure and adjust playback amplifier gain.

Bias Leakage

Method to measure and adjust bias leakage for optimal recording.

Erase Current

Procedure to measure and adjust erase head current.

Measurement and Adjustment Procedures - Part 3

Overall Frequency Response

Dolby NR Circuit Adjustment

MN1400 RS: TERMINATION (BOTTOM VIEW)

MN1400 RS Terminal Functions and Waveforms

Terminal Functions and Waveforms - Part 1

MN1400 RS Terminal Functions and Waveforms - Part 2

Terminal Functions and Waveforms - Part 2

MN1400 RS Terminal Functions and Waveforms - Part 3

Terminal Functions and Waveforms - Part 3

MN1400 RS Terminal Functions and Waveforms - Part 4

Terminal Functions and Waveforms - Part 4

Troubleshooting

Schematic Diagrams

Main Amp Circuit Diagram

Schematic Diagrams (Cont.)

Main Control Section Diagram

Parts Change Notice