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8. Maintenance Service and Trouble shooting
A. Principle integrated circuits
A1. 21 INCH color TV set composed of the following sections
(1) Small signal processing: super monolithic integrated circuits N201(Haier8370). and
memory N202 (AT24C08).
(2) Sound power amplifying: integrated circuits N601 ( AN7522N).
(3) Horizontal and Vertical scan output circuits: Vertical output integrated circuits N401
(LA78040), Horizontal output transistor V401 (TT2140), Horizontal flying back
transformer T401 (BSC25-0283G).
Switch power supply: switch transformer T801 (BCK-07E), power IC N801 (KA5Q0765).
A2.
Main integrated circuits:
(1) NXP 8370
(2) LA7805
AN7522N
Normal
Check VD604~VD607,
C607, N601, N604 etc.
Check to see if the
collector voltage of
VD805 is 14V
Normal
Check to see
if , 8v,
5v is normal
Normal
The failure
ofhorizontal unit
orN201
Microprocessor
Picture IF/sound IF/video processing/H and V
Scan/color decoding
Vertical output integrated circuits
Sound power amplifying integrated circuits
No light and sound
Check to see if
Fuse is normal
Normal
Abnormal
Check the control
voltage of N301 or
CPU power pin
Abnormal
Check N202 ,ect
Abnormal
Check to see 110V、180V
etc. voltage is normal
Abnormal
T est to see all terminal
Resistance of load
Normal
Check to see if
Check switch
rectifying tube
power unit
Normal
Check the
Loader
22
Abnormal
is normal
Abnormal
Change
rectifying diode
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