Teac AG-790 User manual

AAGG--779900
SERVICE MANUAL
AM/FM Stereo Receiver
Effective : April, 2003 S-0092A
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.
CONTENTS
1 SPECIFICATIONS ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・2
2 ADJUSTMENTS AND CHECKS ・・・・・・・・・・・・・・・・・・・・・・・・3
3 EXPLODED VIEWS AND PARTS LIST ・・・・・・・・・・・・・・・・・6
4 PC BOARDS AND PARTS LIST ・・・・・・・・・・・・・・・・・・・・・・・・8

1 SPECIFICATIONS
−2−
Amplifier Section
Output Power....100 + 100 watts RMS (0.9 % THD, 1 kHz, 8 ohms)
Total Harmonic Distortion.................... 0.05 % (at 70 watts,1 kHz)
Input Sensitivity/Impedance .................. PHONO: 5 mV/22 kohms
LINE: 300 mV/22 kohms
Frequency Response ...................... PHONO: 20 Hz–20 kHz, ±3 dB
LINE: 20 Hz–50 kHz, +1/–3 dB
Signal-to-Noise Ratio ................................ PHONO: 80 dB (IHF-A)
LINE: 80 dB (IHF-A)
Tone Control ............................................ BASS: ±10 dB at 100 Hz
TREBLE: ±10 dB at 10 kHz
Loudness Control (Volume at –40 dB Position)..............................
+9 dB at 100 Hz, +8 dB at 10 kHz
FM Tuner Section
(Without notes 98.1 MHz, 65 dBf)
Tuning Range .................... 87.5 MHz–108.0 MHz (100 kHz steps)
Usable Sensitivity (IHF) ............................................ Mono: 20 dBf
50 dB Quieting Sensitivity................ Mono: 39 dBf, Stereo: 46 dBf
Capture Ratio ...................................................................... 2.8 dB
Image Rejection Ratio .......................................................... 20 dB
AM Suppresion Ratio............................................................ 48 dB
Harmonic Distortion (1 kHz) .............. Mono: 0.4 %, Stereo: 0.5 %
Frequency Response................................ 30 Hz–15 kHz, +2/–3 dB
Stereo Separation (1 kHz) .................................................... 35 dB
Signal-to-Noise Ratio ........................ Mono: 57 dB, Stereo: 55 dB
AM Tuner Section
Tuning Range .......................... 530 kHz–1,720 kHz (10 kHz steps)
Usable Sensitivity ............................................................ 55 dB/m
Total Harmonic Distortion .................................... 1 % at 85 dB/m
Signal-to-Noise Ratio ........................................ 48 dB at 85 dB/m
General
Power Requirements.................................. 120 V/230 V, 50-60 Hz
Power Consumption ............................................................ 180 W
AC Outlets ................ Unswitched x 2, Total 100 W max (1 A max)
Dimensions (W x H x D)................................ 435 x 139 x 335 mm
(17-1/8" x 5-1/2" x 13-3/16")
Weight (net) ................................................ 9.4 kg (20-11/16 lbs)
Standard Accessories .................................. AM Loop Antenna x 1
FM ”T” Type Antenna x 1
Remote Control Unit x 1
•Design and specifications are subject to change without notice.
Voltage Conversion
(General export models only)
Be sure to remove the power cord from the AC outlet before
repositioning the voltage converter switch.
1. Locate the voltage selector on the rear panel.
2. Using a flat-bladed screwdriver, set to the appropriate
230V or 120V position according to your area.
IN NORTH AMERICA USE ONLY ON 120 V SUPPLY.

2 ADJUSTMENTS AND CHECKS
−3−
2-1 AMPLIFIER SECTION
Bias Current Adjustment
1. Turn the unit on, and set the input selector switch to "CD".
2. Set 7VR1 and 7VR2 to the center position.
3. Connect the DC voltmeter as shown below after preheating for
10 minutes, and adjust 7VR2 (Lch) so that the voltage
becomes 3.3±1.3mV.
4. Adjust 7VR1 (Rch) in the same way.
7VR17VR2
7R46 7R44
0.33/5W 0.33/5W
DC voltmeter
7R45 7R43
0.33/5W 0.33/5W
DC voltmeter
MAIN PCB

−4−
ITEM SETTING ADJUSTMENT
POINTS ADJUST
2. AM Sensitivity
∫
600 kHz/1500 kHz
50 dB/m
400 Hz (30 % Mod)
ç
REC OUT
AM 600 kHz 2T1 (BLK) Max.
3. AM IF
∫
1000 kHz
50 dB/m
400 Hz (30 % Mod)
ç
REC OUT AM 1000 kHz 2T3 (WHT) Max.
4. FM Sensitivity
∂
90 MHz
10~20 dBf
1 kHz (100 % Mod)
ƒ
REC OUT FM 90 MHz 2L2 (4.5T) Max.
5. FM Distortion
∂
98 MHz
60 dBf
1 kHz (100 % Mod)
©
REC OUT FM 98 MHz 2T4 (PINK) Min. distortion
6. FM Stereo
∂é
98 MHz
60 dBf
Stereo signal L-R
©
REC OUT FM 98 MHz 2T5, 2T6 Min. distortion
1. VT Adjust
å
2R19 (VT)
2J2 (GND)
FM 87.5 MHz 2L3 (3.5T) DC 1.0±0.05V
INPUT OUTPUT AG-790
After adjusting 2TC2, readjust 2T1 at 600 kHz.
AM 1500 kHz 2TC2 Max.
AM 1720 kHz
AM 530 kHz
FM 108.0 MHz
Check
2T2 (RED)
Check
≦8.0V
DC 1.1±0.05V
DC 8.0±0.5V
2-2 TUNER SECTION

−5−
AC Voltmeter
FM Signal Generator
Stereo Signal Generator
Distortion Analyzer
D
E
G
F
AC Voltmeter
AM Signal Generator
B
C
AM Loop
Antenna
60cm
2T3
2T6
2T5
2T2
2T1
2T4
2L2
2L3
2TC2
2R19
2J2 TUNER PCB
+−
DC Voltmeter
A