Sharp Aquos LC-42X20E, Service Manual

Page: 51 / 192

LC-32X20E/S/RU, LC-37X20E/S/RU
4 – 1
LC32X20E
Service Manual
CHAPTER 4.
TROUBLESHOOTING TABLE
[1] TROUBLESHOOTING TABLE
Power unit operation check.
Are the power cord and harness in the unit properly connected?
NO Connect the power cord and harness properly, and turn on the
power.
YES
Is F7000 normal?
NO
Isn't FL7001, L7001, CX7000-1, Z7000, BD7000, TH7000,
Z7001, IC7801, etc. out of order?
Moreover, whether the short-circuit with the circumference circuit
is checked.
YES
Is B_BUS (+280V) output? (Set the main power SW to OFF.)
* When power on/off switch is on
• • •
About +400V
NO Does the PFC circuit operate normally?
(L7800, L7801, T7800, D7806, Q7804-5, IC7800-1 and etc. And,
the circuit around the protection circuit etc. is checked.)
YES
Is a voltage of BU5V applied to pin (8) of connector (PD)?
(Set the main power SW to OFF.) NO Does the switching circuit operate normally?
Check circuit around the primary side (T7901, IC7904, Q7902,
Q7912-4, D7905-6, D7904, D7910, etc.), the secondary side
(D7918, L7900, etc.), the AC_DET circuit (D7911-2, IC7909,
IC7902, Q7910, Q7915, etc.), and the protection circuit.
YES
Are INV60V, UR15, and S15V output as for the power on/off
switch when it is on? NO Does the inverter circuit operate normally?
Check circuit around the primary side (T7001, T7600, IC7603,
IC7601, IC7600, Q7600-2, D7608, D7610, TH7600, etc.), the
secondary side (D7560, L7560, D7150, L7150, L7152, Q7911,
etc.), the PS_ON circuit (Q7300-1, etc.), and the protection cir-
cuit.
YES
Similarly, is PNL12V output as for the power on/off switch when it
is on? NO Check PNL_POW circuit of Q7121-2, etc. and the circuit around
the regulator circuit etc. of IC7121, L7121, D7121, etc.