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BD-HP17U
FLOW CHART No. 6
Is the button switch contact and tightness as specified?
Is the control voltage properly applied at pin (72) (KEY_EJCT)
and pin (73) (KEY_STBY) of IC2503? (While the relevant
button is held down, the "H" level changes to "L" level.)
Check IC2503 and its peripheral circuits. Or replace IC2503
as required.
4. POWER UNIT
FLOW CHART No. 1
Is the fuse working properly?
Does the power come back if the power cable is unplugged
and plugged again after several seconds?
Is AT_12V line working normally?
Is voltage normal at lines AT_-12V and SUB_PC_-8V?
Is pin (17) of IC2503 at "H" level?
Check or replace the peripheral circuits of IC2503.
FLOW CHART No. 2
Is a part of primary circuit causing leaks, short-circuit or open
circuit (L902, L901, D901, T901, IC901, C911 and their
peripheries)?
A button fails to work.
YES
YES
Power does not come ON.
YES
YES
YES
YES
YES
The fuse blows.
Case (1)
NO
Check the relevant switch. Replace it as required.
Check the line between each button and IC2503. Or check the
NO
pull-up resistor at pin (72) of IC2503. (R2578)
NO
If the fuse still blows after replacement, refer to "The fuse blows" in
the FLOW CHART No. 2.
NO
Is a part of primary circuit causing leaks, short-circuit or open circuit
(L901, L902, D901, T901, IC901, C911 and their peripheries)?
NO
Check D952, L951, C955, C958 and C961 of the AT_12V line.
NO
Check each rectifier circuit and SW circuit of the secondary circuit.
NO
Check the power failure detection circuit (IC2508 and its periphery).
Check if the rectifier diode and the circuit are causing short-circuit in
each rectifier circuit of the secondary circuit. (D952)
4 – 9
Case (2)
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