DOWNLOAD Sharp 37GT-25 Service Manual ↓ Size: 1.54 MB | Pages: 28 in PDF or view online for FREE

Model
37GT-25
Pages
28
Size
1.54 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / CTR / version 00
File
37gt-25.pdf
Date

Sharp 37GT-25 Service Manual ▷ View online

1
37GT-25H
TROUBLESHOOTING TABLES......................20
SERVICE MANUAL
SHARP  CORPORATION
CONTENTS
                          
  PAL SYSTEM COLOUR TELEVISION
   SESG37GT25H00
GA-1 
 CHASSIS
In the interests of user safety (required by safety
regulations in some countries) the set should restored
to its original condition and only parts identical to
those specified should be used.
   
    MODEL
 
 37GT-25H
Issued: 11th Oct. ‘00
ELECTRICAL SPECIFICATION.......................2
IMPORTANT SERVICE NOTES.......................3
SERVICE ADJUSTEMENTS.............................4
PRINTED WIRING BOARDS...........................11
SCHEMATIC DIAGRAM, WAVE FORMS.......13
BLOCK DIAGRAM...........................................18
PART LIST.......................................................23
2
37GT-25H
ELECTRICAL SPECIFICATIONS
•Power Input .......................220V-240 Volts AC 50Hz
•Power Consumption
•Audio Power Output Rating .....................2W (MPO)
Speaker............................32
 2W, 8cm Round, 1pc
Normal Operating...................................34W
Stand-by Operating................................7.0W
•White Level
Set brightness control to get total picture tube cathode current of 600 milliamperes under no signal condition.
Maximum necessary correction of each picture tube cathode current to get  8950 degree K-20 MPCD screen
temperature  should not exceed 15% of its original value.
                          X=0.290               Y=0.284
WARNING
The chassis in this receiver is partially live, always use an isolation transformer when
servicing this chassis.
To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer
servicing to qualified service personnel.
Convergence.........................Self Converging System
Focus....................................Bi-Potencial Electrostatic
Sweep Deflection...........................................Magnetic
Specifictions are subject to change without prior notice.
•Aerial Input Impedance
VHF/UHF...........................75 ohm Unbalanced
•Tuning Ranges ............471.25MHz thru 855.25 MHz
     (CH21-CH69)
•Picture Intermediate Frecuencie.....
.........38.9MHz
•Sound  Carrier Trap
.............................32.9MHz
•Adjacent  Sound Carrier Trap
................40.9MHz
•Adjacent  Picture  Carrier Trap
...............30.9MHz
3
37GT-25H
IMPORTANT SERVICE NOTES
SERVICING OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE
Maintenance and repair of this receiver should be done by qualified service personnel only.
When servicing the high voltage system, remove static charge from it by connecting a 10K ohm
resistor in series with an insulated wire (such as test probe) between picture tube ground tag and
high voltage lead. (AC line cord should be disconnected from AC outlet).
1. The Picture tube in this receiver employs Integral Implosion protection.
2. Replace with tube of the same type number for continued safety.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing shatterproof goggles and after discharging the high
    voltage completely.
X-RAY
This receiver is designed so that any X-Ray radiation is kept to an absolute minimum. Since certain
malfunctions and servicing may produce potentially hazardous radiation with prolonged exposure at
close range, the following precautions should be observed:
1. When repairing  the circuit, be sure not to increase the high voltage to more than 25.5 KV, (at beam
    1000
µΑ at short term) for the set.
2. To keep the set in a normal operation, be sure to make it function on 22.4KV
±
1.5KV (at beam
   800
µΑ)  in the case of the set. The set has been factory - adjusted to the above mentioned high
   voltage. Always check the high voltage if there is any possibility that it might have changed as a
    result of the repair.
3. Do not substitute a picture tube with unauthorized types and/or brands which may cause excess
    X-Ray radiation.
BEFORE RETURNING THE RECEIVER
In addition to the above checks, the following safety checks should also be carried out before  returning
the unit to the user.
1. Inspect all leads and dress to make certain that the leads are not pinched or that hardware is not
   lodged between the chassis and other metal parts.
2. Inspect all protective devices such as non-metallic control knobs, insulating fish papers, cabinet
   backs, adjustment and compartment covers or shields, insolation resistor-capacity networks,
   mechanical insulators etc.
4
37GT-25H
SERVICE ADJUSTMENT
SERVICE MODE FUNCTION
This mode funtion is provided to assist with the settings of those adjustments that may vary from one
Picture Tube to another, or between models.
In order to use the Service Mode
1. Press main switch to OFF.
2. Connect Test Pattern signal to antenna terminal.
3. Press 
 
, CH 
∨ 
 buttons and main switch to ON simultaneously.
4. -SERV- will appear on screen. Service mode is now entered.
5. Select adjustment using buttons 
∧ 
CH 
.
   To exit Service Mode, press main switch to OFF or press MENU button on R/C.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
i.
-SERV-
AGC
AFT
H-SHFT
V-SHFT
V-AMPL
V- SLOP
S-CORR
Y-DLY
GAIN R
GAIN G
GAIN B
NVM
Displayed
on screen
Hexadecimal
Range
Function
00
∼ 3F
00 
∼ 7F
(Adjust to 40)
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
00 
∼ 3F
Indicates operative Service Mode.
Auto Gain Control
Auto Frequency Control
Horizontal Position shift.
Vertical Position shift.
Vertical Amplitude shift.
Vertical Symmetry alteration.
S Correction
Luminance Chroma Delay.
Red Gain.
Green Gain.
Blue Gain.
Access to NVM (Non Volatile
Memory).
In order to have access to the desired storage location, buttons 
 
∧ 
should be pressed, as required ,
to obtain a higher or lower location, respectively.
6. For « a » thru « k » Selections.
    Adjustment to a selection cam be made by pressing buttons  
 
∧.
 
  A  colour bar is displayed on the OSD to indicate the adjustment  position, together  with hexadecimal
number ( Not for GII adjustment).
Assigned value
Storage location
HEXADECIMAL
NUMBERS
FF
CURSOR
       BAR
For « i » selection
NVM storage location settings variants.     NVM
   XX
              XX
Page of 28
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Sharp 37GT-25 Service Manual ▷ Download

  • DOWNLOAD Sharp 37GT-25 Service Manual ↓ Size: 1.54 MB | Pages: 28 in PDF or view online for FREE
  • Here you can View online or download the Service Manual for the Sharp 37GT-25 in PDF for free, which will help you to disassemble, recover, fix and repair Sharp 37GT-25 CTR. Information contained in Sharp 37GT-25 Service Manual (repair manual) includes:
  • Disassembly, troubleshooting, maintenance, adjustment, installation and setup instructions.
  • Schematics, Circuit, Wiring and Block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Exploded View and Parts List.