Sharp LC-42SV32B, Service Manual

Page: 32 / 108

LC-42SV32B
32
CHAPTER 4.
TROUBLESHOOTING TABLE
[1] TROUBLESHOOTING TABLE
Power unit operation check.
↓
LINE_FILTER_UNIT:
↓ YES
POWER_UNIT
↓ YES
↓ YES
↓ YES
The sound is not emitted from the speaker though the picture has come out.
↓
No sound output in all modes?
TERMINAL UNIT:
↓
↓ YES
↓ YES
↓ YES
↓ YES
Are the power cord and harness in the unit properly connected?
NO
Connect the power cord and harness properly, and turn on the
power.
Is F901/F902 normal?
NO
LINE_FILTER_UNIT:
Isn't NR901,IC901,L9901,L9902,etc. out of order? Moreover,
whether the short-circuit with the circumference circuit is
checked.
POWER_UNIT:
BD901, FB9902, D9802, etc. out of order?
Moreover, whether the short-circuit with the circumference circuit
is checked.
Is C9824(+390V) output? (Set the main power SW to ON.)
Does the PFC circuit operate normally?
(IC9801, Q9801, L9804 and etc. And, the circuit around the
protection circuit etc. is checked.)
NO
Is a voltage of +5V applied to pin (12,13) of connector (CN902)?
(Set the main power SW to ON.) Does the switching circuit operate normally?
Check circuit around the primary side (IC9301, T9301,
D9335,etc.), the secondary side (D9350, L9350, ZD9301, etc.),
and the protection circuit.
NO
Are 12 and 24V 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 (T9101, Q9101, Q9102,
etc.), the secondary side (D9151, D9153, D9152 etc.), and the
protection circuit.
Is the audio signal output of IC U401 normal?
NO
Check IC U401 and its peripheral circuits.
Is audio signal input to pin (27/28/29/30) of IC U602 (AMP)?
NO
Check the line between IC U401 and IC U602.
Is MUTE circuit [AMP_MUTE_LINE, POWERUP_LINE] normal?
Is the audio signal output of pin (1,2) (R) and pin (3,4) (L) of
CN601(AOUDIO-CONNECTOR) normal?
NO
Check the AMP_MUTE_LINE and POWERUP_LINE. (Q605,
Q610 etc.)
NO Check IC U602 and its peripheral circuits.
Check Speaker (right and left) and wire harness.