Chapter 4. Troubleshooting Table [1] Power Board Troubleshooting Table - Sharp LC-19LE430E Service Manual

LC-19LE430E/UK, LC-22LE430E/UK, LC-26LE430E/UK, LC-32LE430E/UK
CHAPTER 4.
TROUBLESHOOTING TABLE
[1] POWER BOARD TROUBLESHOOTING TABLE
19" TROUBLESHOOTING TABLE
Are the power cord and harness in the unit properly connected?
LINE_FILTER_UNIT:
Is F9901/F9902 normal?
POWER_UNIT
Is (+18V) applied to pin (6) of IC9101 output? (Set the main power
SW to ON.)
Is a voltage of +5.2V applied to pin (4,5) of connector (CN9102)?
(Set the main power SW to ON.)
Are +16V output applied to pin (9, 10) of connector (CN9102) as for
the power on/off switch when it is on?
Similarly, is +16V & +5.2V output as for the power on/off switch
when it is on?
Are +40V output as for the power on/off switch when it is on?
↓
↓ YES
↓YES
↓YES
↓YES
↓YES
↓YES
Power unit operation check.
NO
Connect the power cord and harness properly, and turn on the
power.
LINE_FILTER_UNIT:
Isn't TH9901, L9902, FB9902, and FB9903 out of order?
Moreover, whether the short-circuit with the circumference circuit
NO
is checked.
POWER_UNIT:
BD9901, etc. out of order?
Moreover, whether the short-circuit with the circumference circuit
is checked.
Does the IC9101 circuit operate normally?
NO
(D9103, IC9102, IC9101, Q9103 and etc. And, the circuit around
the protection circuit etc. is checked.)
Does the switching circuit operate normally?
NO
Check circuit around the primary side (T9101, IC9101, D9101,
ZD9106, etc.), the secondary side (D9105, L9104, C9121, etc.)
Does the switching circuit operate normally?
NO Check circuit around the primary side (T9101, IC9101, D9101,
ZD9106, etc.), the secondary side (D9102, L9103, C9103, etc.),
and the protection circuit.
Check IC9101 circuit of Q9103, T9101 etc.
NO
Does the LED boost circuit operate normally?
NO
Check circuit around the second side (L8501, IC8501, Q8501,
D8501 etc.)
46