28JW-73H (serv.man2). GA20 Chassis Training Notes — Sharp TV Service Manual (repair manual)

Model
28JW-73H (serv.man2)
Pages
40
Size
2.38 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / CTR / GA20 Chassis Training Notes
File
28jw-73h-sm2.pdf
Date

View Sharp 28JW-73H (serv.man2) Service Manual online

 
 
 
 
 
50Hz Widescreen 
 Colour Television 
GA20 Chassis 
 
 
 
Technical File 
50Hz Widescreen Colour Television – GA20 Chassis 
 
Sharp Electronics (UK) Ltd 
Technical Support 
 
Contents 
 
Switch Mode Power Supply.................................................................................................................. 1
 
SMPS control IC ............................................................................................................................... 1
 
Features ........................................................................................................................................ 1
 
Supply (Pin 1) ............................................................................................................................ 2
 
Drain (Pin 8................................................................................................................................ 2
 
Control (Pin 3) ........................................................................................................................... 3
 
Burst Standby mode............................................................................................................... 3
 
Hiccup Mode .......................................................................................................................... 3
 
Demagnetization (Pin 4) ............................................................................................................ 3
 
Overvoltage............................................................................................................................ 3
 
Overpower ............................................................................................................................. 3
 
Current Sense (Pin 5) ................................................................................................................ 3
 
Short Winding Protection........................................................................................................ 3
 
Overcurrent ............................................................................................................................ 4
 
Soft Start ................................................................................................................................ 4
 
Drive (Pin 6)............................................................................................................................... 4
 
HT Regulation................................................................................................................................... 4
 
Standby ............................................................................................................................................ 4
 
Standby ............................................................................................................................................ 5
 
Secondary Protection........................................................................................................................ 5
 
Excessive EHT.............................................................................................................................. 6
 
CRT Heater Voltage ...................................................................................................................... 6
 
Horizontal Output Stage ....................................................................................................................... 7
 
Horizontal Drive Mute ....................................................................................................................... 7
 
Horizontal Output Theory.................................................................................................................. 7
 
Vertical Driver..................................................................................................................................... 10
 
Audio Output ...................................................................................................................................... 12
 
LOW PASS FILTER........................................................................................................................ 12
 
Protection ....................................................................................................................................... 13
 
Mute................................................................................................................................................ 14
 
Power On .................................................................................................................................... 14
 
Power Off .................................................................................................................................... 14
 
Off-Mute1................................................................................................................................. 14
 
Off-Mute 2................................................................................................................................ 14
 
Off-Mute 3................................................................................................................................ 14
 
Microprocessor................................................................................................................................... 15
 
Supplies.......................................................................................................................................... 15
 
Reset/Watchdog Circuit .................................................................................................................. 16
 
I
2
C Bus............................................................................................................................................ 16
 
Vertical Protection........................................................................................................................... 16
 
Safety ............................................................................................................................................. 16
 
LED’s .............................................................................................................................................. 17
 
50Hz Widescreen Colour Television – GA20 Chassis 
 
Sharp Electronics (UK) Ltd 
Technical Support 
Issued June 02 
 
Page 1
 
 
 
Switch Mode Power Supply 
 
This SMPS consists of a chopper device Q702, Power Factor Correction (PFC) Q703, SMPS 
controller IC IC701, current sense R715 and soft start R713 & C706  
 
Q702
R708
27R
R715
0R12
R713
33K
C706
0.047µf
R711
1K
C704
1000pf
C710
8200pf
C709
470pf
    D705
Q703
C718
470pf
R722
47K
R720
10K
     D707 C712
470pf
C713
0.033µf
R721
1K
C717
470pf
IC701 Pin 6
(Drive)
IC701 Pin 5
(I
sense
)
IC701 Pin 8
(Drain)
4
7
5
9
+ve
T703
Primary
Winding
 
 
 
SMPS
 CONTROL 
IC 
Features 
 
Universal mains supply operation (70 to 276 V AC) 
Low external component count (High level of integration). 
Valley/zero voltage switching for minimum switching losses 
Efficient quasi-resonant operation at high power levels 
Frequency reduction at low power standby for improved system efficiency (<3 W) 
Burst mode operation for very low standby levels (<1 W) 
Internal start-up current source. 
Safe restart mode for system fault conditions 
Continuous mode protection by means of demagnetization detection (zero switch-on current) 
Accurate and adjustable overvoltage protection 
Short winding protection 
Undervoltage protection (foldback during overload) 
Overtemperature protection 
Low and adjustable overcurrent protection trip level 
Soft (re)start 
Mains voltage-dependent operation-enabling level. 
  
 
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Here you can view online or download Sharp 28JW-73H (serv.man2) Service Manual in pdf. This Service Manual can help you recover, restore, fix, disassemble and repair Sharp 28JW-73H (serv.man2) CTR. Information contained in Sharp 28JW-73H (serv.man2) service manual (repair manual) typically includes:

  • Disassembly, troubleshooting, programming, maintenance, remote, adjustment, installation and setup instructions.
  • Schematics, wiring and block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Parts list (bill of materials).