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SERVICE MANUAL
T-R670
AM / FM Stereo Tuner
CONTENTS
1 SPECIFICATIONS 2
2 ADJUSTMENTS AND CHECKS 3
3 EXPLODED VIEWS AND PARTS LIST 6
4 PC BOARDS AND PARTS LIST 8
NOTES
PC boards shown are viewed from parts side.
The parts with no reference number or no parts number in the
exploded views are not supplied.
As regards the resistors and capacitors, refer to the circuit diagrams
contained in this manual.
£ Parts marked with this sign are safety critical components. They
must be replaced with identical components - refer to the appropriate
parts list and ensure exact replacement.
Effective : April, 2002 S-0056A
1 SPECIFICATIONS
FM Tuner Section
(Without notes 98 MHz, 65 dBf) Voltage Conversion
Tuning Range: 87.5 MHz 108.0 MHz (100 kHz steps)
(General export models only)
Usable Sensitivity (IHF):
Be sure to remove the power cord from the AC outlet before
Mono: 11.2 dBf
repositioning the voltage converter switch.
50 dB Quieting Sensitivity:
Mono: 15 dBf
1. Locate the voltage selector on the rear panel.
Stereo: 20 dBf
2. Using a flat-bladed screwdriver, set to the appropriate
Total Harmonic Distortion (1 kHz):
230V or 120V position according to your area.
Mono: 0.4%
Stereo: 0.5%
IN NORTH AMERICA USE ONLY ON 120 V SUPPLY.
Frequency Response: 30 Hz 15 kHz, +1/ 1.5 dB
Stereo Separation (1 kHz): 40 dB
Signal-to-Noise Ratio:
Mono: 72 dB
Stereo: 70 dB
AM Tuner Section
Tuning Range: 530 kHz 1,720 kHz (10 kHz steps)
Usable Sensitivity: 55 dB/m
Total Harmonic Distortion: 0.8% at 85 dB/m
Signal-to-Noise Ratio: 45 dB at 85 dB/m
General
Power Requirements: 120/230 V AC, 50-60 Hz
Power Consumption: 8 W
Dimensions (W x H x D): 435 x 102 x 270 mm
Weight (net): 3.6kg
Standard Accessories:
AM Loop Antenna x 1
FM T-type Antenna x 1
Matching Transformer x 1
Remote Control Unit (RC-789) x 1
Improvements may result in specifications and features
changing without notice.
2
2 ADJUSTMENTS AND CHECKS
ALIGNMENT INSTRUCTIONS
EQUIPMENT NEEDED:
AM Signal Generator
FM Signal Generator
Oscilloscope
VTVM(AC, DC)
Test loop antenna (AW Adjustment)
Dummy antenna (FM Adjustment)
Stereo signal modulator
Frequency counter
Distortion analyser
IMPORTANT
1. Check power-source voltage.
2. Set the function switch to band aligned.
3. Keep the signal input as low as possible to adjust accurately.
4. Modulation and modulation frequency.
Item
Modulation Modulation frequency
Band
AM 30% 400Hz
FM 100%(75KHz Dev.) 400Hz
ADJUSTMENT POINT
TVR3
T4 T3-2 T3-1
L2
TVC2 T1
TVR4
TVR2 TP1 T1
TVR1 RF1
TVC1
TVR5
T5 T2 P6
P5
MAIN PCB
3
1. AM TRACKING VOLTAGE ADJUSTMENTS
DC VOLTMETER ........................... CONNECT TO TEST POINT P5 and GND
NO. Band Frequency Adjust for Adjustment
1 AM 530KHz 2.2V T1
2 AM 1720KHz 9.5V TVC1
P5
GND
2. AM RF ADJUSTMENT
Signal Generator ........................ Connects to the AM ANT. Coil through the loop antenna.
Adjust for the indication of VTVM of the wave form of scope to be maximum.
BAND Step Frequency Adjust for Adjustment
1 630KHz Maximum sensitivity L2, T2
AM 2 1420KHz Maximum sensitivity TVC2
3 Repeat steps 1 and 2 several times.
3. FM 19kHz REJECTION ADJUSTMENT
NO. Frequency Adjust for Adjustment
1 97.8MHz L rejection T4
2 97.8MHz R rejection T5
3 97.8MHz L, R rejection TVR3
4
4. FM MONO DISTORTION ADJUSTMENT
DC VOLT METER ........................Connect to TP1(-), TP1(+) Through the choke coll (100 H)
Signal Generator........................Connect to FM ANT Jack (FM IN) through the dummy.
Distortion Meter .........................Connect to the output.
NO. Frequency Adjust for Adjustment
1 97.8MHz DC Voltmeter 0V T3-1
TP1(-)
TP1(+)
2 97.8MHz Minimum T.H.D T3-2
3 97.8MHz Minimum T.H.D T1
4 Repeat steps 1 and 2 Several times.
5. FM/AM AUTO STOP LEVEL ADJUSTMENT
FM SIGNAL GENERATOR ........................Connect to FM ANT Jack (FM IN) through the dummy
AM SIGNAL GENERATOR.........................Connect to AM ANT, Coil through the Loop antenna
BAND STEP SIGNAL GENERATOR Adjust for Adjustment
FM 1 97.8MHz 16dB TUNED Display ON TVR1
AM 1 630KHz 74dB TUNED Display ON TVR2
6. FM SEPARATION ADJUSTMENT
NO. Frequency Adjust for Adjustment
1 97.8MHz L separation TVR5
2 97.8MHz R separation TVR4
5
3 EXPLODED VIEWS AND PARTS LIST
21
20
23
19
15
17
16
12
22
6
4
5 18
2
14
13
11
9
10
8
3
7
1
6
EXPLODED VIEW LIST
£
£
£
£
INCLUDED ACCESSORIES
7
4 PC BOARDS AND PARTS LIST
MAIN PCB TRANSFORMER PCB SELECT SW PCB
KEY PCB
8
MAIN PCB ASSY MAIN PCB ASSY
£
£
£
£
£
KEY PCB ASSY
£
£
£
TRANSFORMER PCB ASSY
£
SELECT SW PCB ASSY
£
£
9
SCHEMATIC DIAGRAM T-R670 MAIN PCB, TRANSFORMER PCB, SELECT SW PCB
1 2 3 4 5 6 7 8
A
B
C
D
E
INSTRUCTIONS FOR SERVICE PERSONNEL
BEFORE RETURNING APPLIANCE TO THE CUSTOMER, MAKE LEAKAGE-
CURRENT OR RESISTANCE MEASUREMENTS TO DETERMINE THAT EXPOSED
T-R670
PARTS ARE ACCEPTABLY INSULATED FROM THE SUPPLY CIRCUIT.
AM/FM Stereo Tuner
1 st Issue; October 2001
SCHEMATIC DIAGRAM T-R670 KEY PCB
1 2 3 4 5 6 7 8
A
B
C
D
E
T-R670
AM/FM Stereo Tuner
1 st Issue; October 2001