Sharp DV-NC55S Service Manual page 52

(POWER)
FLOW CHART NO.1
No power
Is the fuse good?
YES
Is the normal state restored when once unplugged
power cord is plugged again after several seconds?
YES
Are AT 5V voltage line normal?
YES
Are STBY 44V, AT 23V, PC 12V, STBY –24V,
STBY 5V and filament voltage lines normal?
YES
Is "H" level applied at pin(1) of IC701?
FLOW CHART NO.2
Fuse blown out.
Case (1)
Check for leak or short-circuiting of primary
circuit part. (L901, T901, Q901-902, etc.)
FLOW CHART NO.3
When the output voltage varies.
Is the photocoupler circuit on the secondary side
operating normally?
YES
Is the control of photocoupler circuit on the primary
side operating normally?
YES
Replace IC701, IC702.
FLOW CHART NO.4
When buzz is heard from the vicinity of power circuit.
Check for short-circuiting of circuit and rectifying diode of each rectifying circuit of secondary
circuit and check for failure of shunt regulator circuit. (D9601-6, IC9601, C9613, C9618)
The fuse blows out even when it is
replaced with new one.
NO
See FLOW CHART NO.2 <Fuse blown out.>.
NO
Check for leak or short-circuiting of primary circuit
part.(L901, D910-3, T901, Q901-902, etc.)
NO
NO
Check each rectifier circuits and short-circuit of
secondary circuit.
NO
Check the power failure circuit.
(Q704 and the peripheral circuit)
Case (2)
Check for short-circuiting of rectifying diode and
circuit in each rectifying circuit of secondary circuit.
(D9601-6)
NO
Check the circuit and replace parts.
(IC901, IC902, IC9601, etc.)
NO
Check the circuit and replace parts.
(IC901, IC902, IC9601, Q902, etc.)
FLOW CHART NO.5
The DVD power cannot be turned on.
Does the change from STANDBY LED indicate
turn-off?
YES
Is the supply voltage of 5V fed to pin(9) of IC8201?
YES
Is the supply voltage about 5V fed to pin(11) of
IC8201?
YES
Is there 4.0MHz oscillation at pins(6) and (8) of
IC8201?
YES
Does the "L" signal inputted at pin(13) of IC8201,
when the POWER button activated on the DVD?
YES
Does the remote control "L" signal inputted at
pin(10) of IC8201, when the POWER button
activated on the remote control unit?
YES
Replace IC8201.
The STANDBY LED indicate it flashing after 0.5sec.
Yes (below, confirmed operating at LED turn-off of 0.5sec interval.)
Are the "P–CON(L)" pulse outputted from the
pin(32) of IC8201?
YES
Does the P–CON switch circuit is operate
normally? (Q9053-5, Q9058, IC9053-54)
YES
Are the "H" pulse inputted into the pin(33) of
IC8201?
YES
Replace IC8201.
YES
NO
Check the AT 5V line.
NO
Check the IC8202.
NO
Check the FL8201 and IC8201.
NO
Check the S5001 and POWER KEY line.
Check the line between the remote control
NO
receiver and the pin(10) of IC8201.
Replace IC8201.
NO
NO
Check each component and if poor the replace.
NO
Check or replace D9091-95.