Sharp BD-HP22SB Service Manual page 19

FLOW CHART No.6
Is the button switch contact and tightness as specified?
Is the control voltage properly applied at pin (74) (KEY_EJCT)
and pin (75) (KEY_STBY) of IC2504? (While the relevant
button is held down, the "H" level changes to "L" level.)
Check IC2504 and its peripheral circuits. Or replace IC2504
as required.
4. ETHER UNIT
FLOW CHART No.1
Still malfunctioning even by replacing the cable.
Is any signal input into pins (1)/(2)/(4)/(5) of the J7001?
Is any signal input into pins (28)/(29)/(31)/(32) of the IC7001?
Is 50MHz clock detected at pin (14) of IC7001?
Is 3.3V supplied to pins (7)/(25)/(30)/(33)/(35) of IC7001?
Is any signal input into the R7004 - 7012?
Is 50MHz clock detected of R7027?
Check or replace the peripheral circuits of IC7201.
A button fails to work.
YES
YES
Internet connection impossible with Ether terminal.
YES
NO
YES
YES
YES
NO
YES
NO
Check the relevant switch. Replace it as required.
Check the line between each button and IC2504. Or check the
NO
pull-up resistor at pin (74) or (75) of IC2504. (R2578, R2507)
NO
Cable defective.
YES
Check the J7001 contact.
YES
Check the peripheral circuits of J7001.
NO
Check or replace the peripheral circuits of X7001 and R7024.
NO
Check the peripheral circuits of FB7001, FB9004 and IC9002.
YES
Check or replace the peripheral circuits of IC7201.
NO
Check or replace the peripheral circuits of IC7001.
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BD-HP22SB