Sharp 66GS-62 (serv.man23) Service Manual / Technical Bulletin ▷ View online
CTV 2004 03 06
Month of Issue:
March 2004
Classification:
White
TELEVISION TECHNICAL BULLETIN
Page 1 of 1
Sharp Electronics (UK) Limited
Reference AvW 10 03 2004 - 6
Revision 1
White – Carry out as required
Yellow – Carry out as required and whenever the unit comes in for service
Red – Carry out on all units
MODEL
66GS62H
Picture Problems with the GA10 Chassis
Red, Green and Blue Lines at the Top of the Picture
Lines at the top of the picture can be caused by corruption of the memory, check and set the NVM locations as follows.
The fault can also happen if the +25V is low to the vertical flyback circuit or if there is a fault in the vertical, reducing the
flyback level.
Lines at the top of the picture can be caused by corruption of the memory, check and set the NVM locations as follows.
The fault can also happen if the +25V is low to the vertical flyback circuit or if there is a fault in the vertical, reducing the
flyback level.
24645 Type NVM
24C16 Type NVM
Page
Address
Value
Page
Address
Value
0C
EB
10
05
D6
10
0C
F7
1A
05
E2
1A
Blank raster
A blank raster can also be caused by various faults in the vertical stage, and is normally connected to the loss of the
flyback pulse. A portion of the flyback pulse is fed back into pin 94 (VPROT) of IC1001, this is a 5V 50Hz pulse.
Normally Q502 and Q503 go leaky or short circuit, leading to loss of the +25V supply and removal of the VPROT signal.
A blank raster can also be caused by various faults in the vertical stage, and is normally connected to the loss of the
flyback pulse. A portion of the flyback pulse is fed back into pin 94 (VPROT) of IC1001, this is a 5V 50Hz pulse.
Normally Q502 and Q503 go leaky or short circuit, leading to loss of the +25V supply and removal of the VPROT signal.
A low or missing +25V can also cause this problem. This supply comes from pion 1 of the line output transformer via
R530, D510 and C520. Any of these components can fail. Note that failure of the vertical output IC , IC501, can also
cause a blank raster.
R530, D510 and C520. Any of these components can fail. Note that failure of the vertical output IC , IC501, can also
cause a blank raster.
This fault can also be caused by a corrupted NVM - either reprogram or blank the NVM.
Low Brightness in the Service Mode Only
Due to a corruption in the EEPROM, when entering the service mode on some earlier GA10 chassis, the picture is too
dark. By using the channel up button to step to one of the RGB gain settings, the brightness will increase to a
watchable level. Service adjustments can now be carried out normally.
Due to a corruption in the EEPROM, when entering the service mode on some earlier GA10 chassis, the picture is too
dark. By using the channel up button to step to one of the RGB gain settings, the brightness will increase to a
watchable level. Service adjustments can now be carried out normally.
This is not considered to be a major problem as it does not affect the customers viewing. To cure the problem would
require replacing IC1002 and IC1003 and is therefore not recommended.
require replacing IC1002 and IC1003 and is therefore not recommended.
REF NO
DESCRIPTION
PART NUMBER
PRICE CODE
IC501
IC, TDA7480
VHITDA7480/-1
AK
Q502
Transistor, KSA928A
RH-TX0201BMZZ
AC
Q503
SMD Transistor, SUD15N06-90L
RH-TX0239BMZZ
AE
C520
Capacitor, 470
µ
F 35V
VCEAHA1VN477M
AC
R530
Resistor, 4.7
Ω
0.5W
RR-XZ0208BMZZ
AA
D510
Diode, 1N4935
RH-DX0577BMZZ
AE
Display
