Sharp LC-32A28L Service Manual page 36

LC-32A28L, LC-42A48L
42" TROUBLESHOOTING TABLE
↓
Are the power cord and harness in the unit properly connected?
↓ YES
LINE_FILTER_UNIT:
Is F901 and F902 normal?
↓YES
POWER_UNIT
Is BD901 (+320V) output? (Set the main power SW to OFF.)
* When power on/off switch is on ‧‧‧ About +400V
↓YES
Is a voltage of +5V applied to pin (11,12) of connector (CN902)?
(Set the main power SW to OFF.)
↓YES
Are +24V output as for the power on/off switch when it is on?
↓YES
Similarly, is +12V output as for the power on/off switch when it is
on?
Power unit operation check.
NO
Connect the power cord and harness properly, and turn on the
power.
LINE_FILTER_UNIT:
Isn't L901,L902,RV902,RV904,C908,C909,, etc. out of order?
Moreover, whether the short-circuit with the circumference circuit
NO
is checked.
POWER_UNIT:
BD901,Q901,Q920,Q919,IC903, etc. out of order?
Moreover, whether the short-circuit with the circumference circuit
is checked.
NO
Does the PFC circuit operate normally?
(L903, Q902, D903, IC902 and etc. And, the circuit around the
protection circuit etc. is checked.)
NO
Does the switching circuit operate normally?
Check circuit around the primary side (T904, IC903, ZD910,
ZD911, ZD913, D908, D924, D939, ZD912, Q924 ,IC911 etc.),
the secondary side (D927, L907, IC913, Q918 etc.), and the
protection circuit.
Does the inverter circuit operate normally?
NO
Check circuit around the primary side (T905,Q919,Q920,IC901,
D931,D932,Q922,D933,Q917,Q923 etc.), the secondary side
(D901,D902,L906 , IC914, IC910, etc.), the STANDBY circuit
(Q915, etc.), and the protection circuit
Check +12V circuit of D928, L909, etc.
NO
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