XOCECO LC-20Y15, Service Manual

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2
0
2. With picture and without sound when turning on:
3. When receiving TV signal, there is no picture or dark snow:
Confirm the +5V, +32V power supply of TUNER, c5V, +9V power supply of IF amplifier is normal.
If they are normal, check whether peripheral circuit of the TUNER or IF amplifier is normal. If they are all
no problem, then 8125 or its input signal is abnormal.
4. In TV channel, the picture or sound is abnormal; the frequency of the menu is different from the actual
frequency.
Connect the signal cable; manually adjust the frequency to conform to the actual frequency. Enter into
service menu; check AFT value should be about 1.6V. If the difference is serious (the difference is larger
than 0.4V), open the cabinet and adjust the transformer until the value of AFT is 1.6V.
Increase the volume;
check whether every
channel has no sound
Check if the no sound channel from the
signal input to sound processing IC
IC15900 is normal
Check whether the signal
output by 15900(IC) is
normal
15900(IC) or peripheral circuit
does not work normally
Sound amplifier or
peripheral circuit does
not work normally
N
Y
Y
N