Read Sharp BD-HP21H (serv.man2) Service Manual online
BD-HP21U/S/H/A/X/RU/SB,BD-HP50U/X
2 – 19
The RS232C interface fails to control the system.
Is the control signal being sent from the PC inputted via pin (2)
of SC4701?
of SC4701?
YES
YES
Check IC2504 and its peripheral circuits as well as the power supply
line. Replace as required.
line. Replace as required.
Check the line between pin (2) of SC4701 and pin (8) of IC4701.
Is the signal inputted to pin (36) of IC2504?
Is the signal outputted from pin (37) of IC2504?
Check the line between pin (9) of IC4701 and pin (36) of IC2504.
NO
NO
Check the line between pin (11) of IC4701 and pin (37) of IC2504.
NO
Is the signal inputted to pin (8) of IC4701?
NO
Check the cable and the PC settings.
NO
YES
Is the signal outputted from pin (9) of IC4701?
Check IC4701 and its peripheral circuits as well as the power supply
line. Replace as required.
line. Replace as required.
NO
YES
Is the signal inputted to pin (11) of IC4701?
YES
YES
NO
Is the signal outputted from pin (13) of IC4701?
YES
NO
Is the signal inputted to pin (3) of SC4701?
YES
Check the cable or replace SC4701.
Check IC4701 and its peripheral circuits as well as the power supply
line. Replace as required.
line. Replace as required.
Check the line between pin (3) of SC4701 and pin (13) of IC4701.
FLOW CHART No.8 (HP50U only)
* Signal level
IC4701
ЊSC4701㧦
INPUT
"L"
㧦-15V㨪-3V
OUTPUT
"L"
㧦-5.4V
"H"
㧦5.4V
IC4701
ЊIC2504㧦
"L"
㧦0V
"H"
㧦5V
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