Sharp 28KF-84H (serv.man18) Service Manual ▷ View online
1
28KF-84H
PAL I
SYSTEM COLOUR TELEVISION
SERVICE MANUAL
GA-200
CHASSIS
In the interests of user safety (required by safety
regulations in some countries) the set should be re-
stored to its original condition and only parts identi-
cal to those specified should be used.
regulations in some countries) the set should be re-
stored to its original condition and only parts identi-
cal to those specified should be used.
CONTENTS
ELECTRICAL SPECIFICATIONS ................... 3
IMPORTANT SERVICING NOTES ................. 4
CONTROLS & TERMINALS ........................... 5
ADJUSTMENT PROCEDURES ...................... 6
LED FLASHING CODES ............................... 13
PRINTED WIRING BOARDS ........................ 14
COMPONENT LOCATION TABLES ............... 22
CHASSIS LAYOUT ......................................... 29
IMPORTANT SERVICING NOTES ................. 4
CONTROLS & TERMINALS ........................... 5
ADJUSTMENT PROCEDURES ...................... 6
LED FLASHING CODES ............................... 13
PRINTED WIRING BOARDS ........................ 14
COMPONENT LOCATION TABLES ............... 22
CHASSIS LAYOUT ......................................... 29
SCHEMATIC DIAGRAMS ............................... 32
BLOCK DIAGRAM ....................................... 45
TROUBLESHOOTING TABLES ..................... 46
ICs ADDITIONAL INFORMATION .................. 51
PARTS LISTING ............................................. 67
SERVICING NOTES.................................... 77
SOURCE OF DOCUMENTATION .................. 79
BLOCK DIAGRAM ....................................... 45
TROUBLESHOOTING TABLES ..................... 46
ICs ADDITIONAL INFORMATION .................. 51
PARTS LISTING ............................................. 67
SERVICING NOTES.................................... 77
SOURCE OF DOCUMENTATION .................. 79
SHARP CORPORATION
MODEL
28KF-84H
SE
0028
KF84H00
Issued:24
th
July 2003
2
28KF-84H
Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc.
If only part number changes are required, just change part number directly the part number in the Parts Listing 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 the part number in the Parts Listing Section.
If you need more information, please refer to the Technical Report (Bulletin).
SERVICE MANUAL UPDATE LOG SHEET
Part No.
Technical Report No.
Technical Bulletin No.
Technical Bulletin No.
Cause / Solution
Page No.
Application
Data /Serial No.
Data /Serial No.
3
28KF-84H
ELECTRICAL SPECIFICATIONS
•
White Level
Set brightness control to get total picture tube cathode current of 600
µ
A under no signal condition.
Maximum necessary correction of each picture tube cathode current to get 8950 degrees
K-20 MPCD
screen temperature should not exceed 15% of its original value.
X=0.290 ± 0.015 Y=0.284 ± 0.015
WARNING
The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug
and power receptacle, when servicing this chassis.
To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to
qualified service personnel.
and power receptacle, when servicing this chassis.
To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to
qualified service personnel.
•
Focus ................. High Bipotencial Electrostatic
•
Sweep Deflection ............................. Magnetic
•
Picture Intermediate frequency .......... 38.9MHz
•
Sound Carrier Trap ........................... 32.9MHz
•
Adjacent Sound Carrier Trap ............. 40.9MHz
•
Adjacent Picture Carrier Trap ........... 30.9MHz
•
Aerial Input Impedance
VHF/UHF ................. 75 ohm Unbalanced
•
Tuning Ranges ..... 45.75MHz thru 855.25 MHz
VHF: IR A - J / CC01-CC68 (Hiperband)
UHF: I21 - I69 CH
UHF: I21 - I69 CH
Specifications are subject to change without prior notice.
•
Power Input .................... 220V-240 Volts AC 50Hz
•
Power Consumption
Normal Operation (Method IEC60107) ...............100W
Stand-by Operation ..........................................1.5W
Stand-by Operation ..........................................1.5W
•
Audio Power Output Rating (MPO) / Impedance
Internal Left Speaker ................................. 10W, 7
Ω
Internal Right Speaker ............................... 10W, 7
Ω
•
Speakers
Left / Right ................................................. 12 x 6cm
•
Convergence (Maximum Misconvergence)
Static (Centre) between any two colours ... 0.03 cm
Dynamic after static equals zero
Dynamic after static equals zero
Within 28 x 15 cm rectangle ........... 0.13 cm
56 x 30 cm rectangle........................ 0.15 cm
56 x 30 cm rectangle........................ 0.15 cm
Everywhere else .......................................... 0.18 cm
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28KF-84H
IMPORTANT SERVICING NOTES
Only qualified service personnel are allowed to carry out maintenance and repair of this receiver.
Servicing of High Voltage System and CRT
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
receiver.
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
receiver.
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:
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 33 KV, (at a
instantaneous beam current of 1800
µ
A
)
.
2. Ensure that during normal operation the EHT does not exceed 30 KV (at a beam current of 1300
µ
A). This
level has been preset in the factory. Always check that this level has not been exceeded after carrying out
any repair on the receiver.
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.
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.
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 nonmetallic control knobs,
insulating fish papers, cabinets backs, compartment covers or shields, mechanical insulators, etc.