Sangean ATS-818 - Service Manual

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PLL SYNTHESIZED worLbD BAND RECEIVER
The SANGEAN ATS-818 is the WORLD'S ONLY Portable World Band Receiver offering
more features and performance than many expensive table top Short Wave
Receivers.
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* All SW Bands from 120m to 11m _—_* 45 Memory Presets * RF Gain Control
* Radio/Buzzer Clock Alarm * AM Wide/Narrow Filter * Dual Conversion Receiver
* BFO for Single Side Band & CW * Dual Time Display for Local * Signal Strength & Battery
* Continuous AM Coverage and UTC Time Indicator
from 150-29999KHz plus FM 87.5- * Adjustable Sleep Timer * Tone Control & Safety Lock
108MHz
* Five Tuning Methods: Direct frequency Input, Auo Scan, Manual Scan, Memory Recall, Rotary Dial
SPECIFICATIONS ] FREQUENCY 2.300-2.495MH2(120m) 3.200-3.400(90m) 3.900-4000(75m) 4.750-5.060(60m)
5.950-6200MHz(49m) 7.100-7.300(4 1m) 9.500-9.900(3 1m) 11.650-12.050(25m)
| 413.600-13.800(21m) 15.100-15.600(19m) 17.550-17.900(16m) 21.450-21.850(13m)
| 25.670-26.100(11m)
SEMI-CONDUCTORS: 1 LSI, 12 IC’s, 8 FET's, 48 Trans., 45 Diodes. 2 LED | OUTPUT PWR: 800mW | SPKR: 4 inch, 4 ohm
BATTERIES: 4/1.5VDC “D” Size Radio Power & 3/1.5VDC AA Back-Up Power _| ACCESSORIES: AC Adapt, Ext. Antenna Adapt, Shortwave HandBook
2651 Troy Avenue, South El Monte, CA 91733
AMERICA, INC. Tel: (818) 579-1600 Fax: (818) 579-6806

Summary

Specifications

Disassembly Instructions

Block Diagram

Alignment Instructions

Alignment For Clock Time Accuracy

Adjust TC401 to set clock time accuracy.

Alignment For PLL Frequency

Adjust TC4 for PLL frequency accuracy at 108 MHz.

Alignment For AM 2 nd Local OSC

Adjust L14 for AM 2nd Local OSC frequency.

Alignment For AM 2 nd IF

Adjust T4 and T6 for AM 2nd IF frequency response.

Alignment For FM IF

Adjust T5 and T7 for FM IF response curve.

Alignment For AM Sensitivity

Adjust T1, T3, and L14 for AM sensitivity.

Alignment For BFO

Adjust TC3 for minimum reading on SSVM for BFO alignment.

Alignment For FM Sensitivity

Adjust L11, L12, TC1, TC2 for FM sensitivity.

Alignment For MPX

Adjust SVR2 for MPX frequency range.

Alignment For Indication Level of Battery

Adjust SVR5 to calibrate battery level indicator.

Alignment For Signal Strength Level

Adjust SVR3 and SVR4 for signal strength level readings.

Alignment For 450 kHz Trap

Adjust T8 for minimum audio output in 450kHz trap alignment.

Alignment For FM Station Detection

Adjust SVR1 for FM station detection voltage difference.

Troubleshooting Flow Chart

Weak Sensitivity on FM Mode

Troubleshooting steps for weak FM sensitivity.

Weak Sensitivity in AM Band

Troubleshooting steps for weak AM band sensitivity.

PLL Does Not Work

Troubleshooting steps when the PLL circuit is not functioning.

Power Cannot Be Turned On

Troubleshooting steps when the device cannot be powered on.

Wiring Diagram

Main PCB Chip Side

Main PCB Top View

Control PCB Chip Side

Control PCB Top View

Electrical Parts List

Semiconductor Lead Identifications

Exploded View

Mechanical Parts List

IC Circuit Block Diagram

IC3-CX7961 A-1

Block diagram for IC3 CX7961A-1.

IC4-TC74 HC148 AP

Block diagram for IC4 TC74HC148AP.

IC1-TA7758 P

Block diagram for IC1 TA7758P.

IC2-AN7415

Block diagram for IC2 AN7415.

IC5,6-TA75339 AP;P

Block diagram for IC5,6 TA75339AP/P.

IC7,8-AN7141 N

Block diagram for IC7,8 AN7141N.

IC9-LA5003

Block diagram for IC9 LA5003.

IC401,402-S81237 AG-RE-T2

Block diagram for IC401,402 S81237AG-RE-T2.

IC403-UPD75308 GF-177

Block diagram for IC403 UPD75308GF-177.

ICS & Transistors Voltage List

Schematic Diagram

Sangean ATS-818 Specifications

General

Type	Portable Radio
Modulation	AM / FM
Headphone Jack	3.5 mm
Display	LCD
Tuning System	PLL Synthesized
Frequency Range	FM: 87.5-108 MHz, MW: 522-1620 kHz, SW: 1.711-29.999 MHz
Tuning Steps	FM: 50 kHz, MW: 9 kHz, SW: 5 kHz
FM Sensitivity	3 μV
SW Sensitivity	20 μV
IF Frequencies	FM: 10.7 MHz, AM: 455 kHz
Audio Output Power	0.5 W
Antenna	Telescopic antenna for FM
Power Source	AC adapter or batteries
Battery Life	Up to 20 hours
Memory Presets	10 FM, 5 MW, 5 SW