AS
FILE NO.
SERVICE MANUAL
Remote Control Digital
Color Television
HT28745
(U.S.A.)
(CANADA)
ORIGINAL VERSION
Chassis No. 28745-00
NOTE: Match the Chassis No. on
the unit’s back cover with
the Chassis No. in the
Service Manual.
If the Original Version
Service Manual Chassis
No. does not match the
unit’s, additional Service
Literature is required. You
must refer to “Notices” to the
Original Service Manual
prior to servicing the unit.
Contents
Safety Instructions . . . . . . . . . . . . . . . . . . 2
Service Adjustments . . . . . . . . . . . . . 3 - 17
Service Hints . . . . . . . . . . . . . . . . . . . . . . 18
Mechanical Disassemblies. . . . . . . . . . . 19
Chassis Electrical Parts List . . . . . . 20 - 36
Cabinet Parts List . . . . . . . . . . . . . . . . . . 37
Component and Test Point
Locations . . . . . . . . . . . . . . . . . . . 38 - 45
Block Diagrams . . . . . . . . . . . . . . . . 46 - 51
Troubleshooting Flow Charts . . . . . 52 – 54
Control Port Function . . . . . . . . . . . . . . . 55
Schematic Inserts . . . . . . . . . . . . . . 57 – 72
Schematic Notes . . . . . . . . . . . . . . . . . 57
Pin Layouts . . . . . . . . . . . . . . . . . . . . . 57
Capacitor and Resistor Codes . . . . . . 57
Board Connections & Locations. 58 – 60
Waveforms. . . . . . . . . . . . . . . . . . 58 – 60
Main Board. . . . . . . . . . . . . . . . . . 61 – 64
Power and Deflection Board. . . . 65 – 66
Front Board . . . . . . . . . . . . . . . . . 67 – 68
AV Switching / Video Board . . . . 69 – 72
CRT Socket / VM Board . . . . . . . . 69 – 72
Specifications
Power Rating . . . . . . . . . . . . . . . . . . . . . 120V, 60Hz
140W (Avg), 2.5A (Max)
Antenna Input Impedance . . . . . . . . . . . . . . . . . 75
Ω
UHF/VHF/CATV
Digital
Receiving Channel . . . . . . . . . . . . . . . . 2 - 13 (VHF),
14 - 69 (UHF),
01, 14 - 94, 95 - 125 (CATV)
1 - 99 (Digital)
Remote Ready . . . . . . . . . . 32 Key Remote Control
Sound Output . . . . . . . . . . . . . . . . . . . . . . 5.0 W/CH
Intermediate Frequency
Picture IF Carrier . . . . . . . . . . . . . . . . . . 45.75MHz
Sound IF Carrier . . . . . . . . . . . . . . . . . . 41.25MHz
Color Sub Carrier . . . . . . . . . . . . . . . . . 42.17MHz
Picture Tube . . . . . . . . . . . . . . . . . W70ELC011X221
Semiconductors
Integrated Circuits . . . . . . . . . . . . . . . . . . . . . . . 30
Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Except within Tuners, RC Pre-Amp. & Digital Module
Cabinet Dimensions
Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858 mm
Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543 mm
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538 mm
REFERENCE No.
SM
780106
HT28745, H3JAM, PRODUCT CODE 111375980
INTEGRATED
INTEGRATED
DIGITAL TUNER
DIGITAL TUNER
D I G I T A L
D I G I T A L
DOLBY
DOLBY
CH
CH
VOL
VOL
POWER
POWER
Servicing should be performed by only trained and qualified service personnel.
