Read Sharp 51GT-25 (serv.man2) Service Manual online
1
51GT-25H
GA-1
CHASSIS
MODEL
51GT-25H
Issued: 31st Oct ‘00
SERVICE MANUAL
SHARP CORPORATION
PAL SYSTEM COLOUR TELEVISION
SESG51GT25H00
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.
regulations in some countries) the set should restored
to its original condition and only parts identical to
those specified should be used.
ELECTRICAL SPECIFICATION........................3
IMPORTANT SERVICING NOTES ..................4
SERVICE ADJUSTMENTS...............................5
PRINTED WIRING BOARDS...........................12
SERVICE ADJUSTMENTS...............................5
PRINTED WIRING BOARDS...........................12
SOLID STATE DEVICE BASE DIAGRAM.......20
SCHEMATIC DIAGRAM, WAVE FORMS........21
SCHEMATIC DIAGRAM, WAVE FORMS........21
TROUBLESHOOTING TABLES......................28
PARTS ALLOCATION TABLES.......................16
PART LIST.......................................................30
BLOCK DIAGRAM...........................................26
CONTENTS
FASTTEXT
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51GT-25H
Use this page to keep any special servicing information as Thecnical Report (Bulletin), Technical Information, etc.
If only part number changes are required, just change part number directly on Part List Section.
If you need more information, please refer to the Technical Report (Bulletin).
If only part number changes are required, just change part number directly on Part List Section.
If you need more information, please refer to the Technical Report (Bulletin).
SERVICE MANUAL UPDATE LOG SHEET
Part #
Technical Report #
Technical Bulletin #
Technical Bulletin #
Cause / Solution
Page #
Application
Data /Serial #
Data /Serial #
3
51GT-25H
ELECTRICAL SPECIFICATIONS
•Power Input .......................220V-240 Volts AC 50Hz
•Power Consumption
•Audio Power Output Rating .....................4W (MPO)
Speaker..........................16
Speaker..........................16
Ω
4W, 10cm Round, 1pc
Normal Operation....................................52W
Stand-by Operation.................................7.0W
Stand-by Operation.................................7.0W
•White Level
Set the brightness control, with no signal connected, so that the CRT cathode current is 600mA. The maximum
correction applied to each cathode current to achieve a screen temperature of 8950 degrees K-20 MPCD should
not exceed 15% of its original value.
correction applied to each cathode current to achieve a screen temperature of 8950 degrees K-20 MPCD 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.
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
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 Frecuency.....
.........38.9MHz
•Sound Carrier Trap
.............................32.9MHz
•Adjacent Sound Carrier Trap
................40.9MHz
•Adjacent Picture Carrier Trap
...............30.9MHz
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51GT-25H
IMPORTANT SERVICING NOTES
SERVICING OF HIGH VOLTAGE SYSTEM AND CRT
Only qualified service personnel are allowed to carry out mintenance and repair of this receiver.
It is important that the static charge is removed from the high voltage system when carrying out
work on the receiver. This can be achieved by connecting a 10K resistor (with a suitably insulated
lead) from the CRT cavity connector to the CRT ground tag. This must be carried out with the AC
supply disconnected from the reciver.
Note the following:
work on the receiver. This can be achieved by connecting a 10K resistor (with a suitably insulated
lead) from the CRT cavity connector to the CRT ground tag. This must be carried out with the AC
supply disconnected from the reciver.
Note the following:
•
The CRT in this receiver employs Integral Implosion Protection.
•
If the CRT has to be changed it MUST be replaced with the correct type for continued safe
working
•
DO NOT lift the CRT by its neck.
•
When handing the CRT, ensure that shatterproof goggles are worn.
•
Ensure that the CRT is discharge before handling.
X-RAY
This receiver is designed to keep any x-ray emission to an absolute minimum. Some fault conditions
and servicing procedures may produce potentially hazardous x-ray radiation levels. This is a problem
when in close proximity to the receiver for long periods of time. To reduce any risks associated with
this, please observe the following precautions:
and servicing procedures may produce potentially hazardous x-ray radiation levels. This is a problem
when in close proximity to the receiver for long periods of time. To reduce any risks associated with
this, please observe the following precautions:
1. When undertaking any servicing on this chassis, DO NOT increase the EHT to more than 29.5 KV,
(at a instantaneous beam current of 1000
(at a instantaneous beam current of 1000
µΑ).
2. Ensure that during normal operation the EHT does not exceed 27.5KV
±
1.5KV (at a beam current of
800
µΑ). Tjis level has been pre-set in the factory. Always check that this level has not been exceeded
after carrying out any repair on the receiver..
3. DO NOT replace the CRT with any other type than that specified in the parts listing as this may
cause excessive x-ray radiation.
3. DO NOT replace the CRT with any other type than that specified in the parts listing as this may
cause excessive x-ray radiation.
BEFORE RETURNING THE RECEIVER TO THE CUSTOMER
In addition to the above checks, the following should also be carried out before returning the receiver
to the customer.
to the customer.
1. Inspect all the leads to ensure that they are dressed correctly and that they are not obstructed or
pinched by any other parts.
2. Ensure that all protective devices are in good condition. These will include non-metallic control
knobs, insulating fish papers, cabinets backs, compartment covers or shieds, mechanical insulators,
etc.
pinched by any other parts.
2. Ensure that all protective devices are in good condition. These will include non-metallic control
knobs, insulating fish papers, cabinets backs, compartment covers or shieds, mechanical insulators,
etc.
