XOCECO LC-42HW36, Руководство по обслуживанию

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18
(2) picture and operation are normal, but sound is abnormal:
5.
Power mode
The unit adopt PHILP power manage IC, which can control the power and the power consumption
is lower than 1W at stand-by and it has the function of timer setup.
Working principle of power:
The input AC power via EMC filter and rectification circuit, it sent to PFC(power factor correct L6563)
to output DC400V, which will be separated into two ways, one way via standby circuit (isolation D/D
convert FSDH321) output 5V and 32V; another way via semi-bridge circuit(TEA1610T) output 24V,
18V, etc. At standby, power board send out Vsb(3.3V) to cut off 5VSC, 32VSC output by the control
of Standby signal and stop working of PFC circuit(L6563) and semi-bridge (TEA1610T). When turn
Check the back level
circuit of IC output
(short or joint soldering) N1 is abnormal, replace it
when the power supply is
normal
Check if NU8 5# 8#
output sound signal
Check if the back level
circuit of NU8 output
is short or open
Check if NU8
7# has +5V
power supply
Check if NU8 pin1-4
input high-low level
digital signal or sine wave
Replace NU8
Check the
power supply
Replace
N1
No
No
No
Yes Yes
Yes
Rectify
isolation
backlight
amplifier
isolation
isolation