Sony ICF-SW77 - SERVICING NOTES; Notes on Repairing Microcomputer Board; Microcomputer Board Checking; LCD 802 Replacing Procedure

TABLE OF CONTENTS
Section Title Page
Specifications . 1
Features . 2
1. SERVICING NOTES
Notes on Repairing Microcomputer Board * • • * 3
Microcomputer Board Checking . 3
LCD 802 Replacing Procedure . 4
Points of the Frequency Coverage
Adjustment . 5
2. GENERAL
Location and Function of Controls . 6
Power Sources . 8
Setting the Clock . 8
Tips for Better Reception . 9
Preset Station Tuning . 10
Direct Tuning . 12
Manual Tuning . 13
Scan Tuning . 14
Memorizing and Editing Stations . 14
Sleep Timer Operation . 17
How to Set the Timer . 17
External Antenna Connection . 18
Recording a Broadcast . 19
3. ELECTRICAL ADJUSTMENTS
Main VCO Frequency Adjustment . 20
Sub VCO Freerun Frequency Adjustment . 20
X501 (6.275 MHz) X’tal Adjustment . 21
AM 1st IF Adjustment . 21
FM IF Adjustment . 22
SYNC USB/LSB Zero-beat Adjustment . 22
AM Tracking Adjustment . 22
FM Tracking Adjustment . 23
FM Stereo Adjustment . 23
FM Scan Stop Adjustment . 24
Clock Frequency Adjustment
(Mcrocomputer Board) . 24
4. DIAGRAMS
4-1. IC Pin Function . 26
4-2. Block Diagram . 30
4-3. Microcomputer Section
Printed Wiring Boards . 34
4-4. Microcomputer Section Schematic Diagram • • * 39
4-5. Signal Section Schematic Diagram . 44
4-6. Signal Section Printed Wiring Boards . 49
5. EXPLODED VIEWS . 59
6. ELECTRICAL PARTS LIST 61
ICF-SW77
SECTION 1
SERVICING NOTES
[Note on Repairing Microcomputer Board]
The user’s program schedule data is memorized in
E^ROM IC806.
When repairing by the microcomputer board replacement,
unsolder IC806 on the user’s board and solder it on the new
board.
[Microcomputer Board Checking]
Checking the microcomputer board alone is possible.
1) Disconnect the flexible board from CN401 on the
signal board.
2) Connect +6 V and ground to the points on the micro¬
computer board in the following figure.
3) Short-circuit between +3VCPU and OFF LOCK lands
(OFF LOCK key ON state).
4) Short-circuit TST lands.
5) Pressing S806 ON/OFF key turns the microcomputer
board on or off.
6) Release the shorted TST, +3VCPU, and OFF LOCK
lands.
• POWER SUPPLY
[MICROCOMPUTOR BOARD]
- Component Side -
I GND
• +3VCPU - OFF LOCK LANDS
[MICROCOMPUTOR BOARD]
- Component Side -
S 8 4 8
|RE SET |
[MICROCOMPUTOR BOARD]
- Component Side - short-circuit
- 3 -