Usb Connection Is Impossible - Sharp TQ-GX30E Service Manual

GX30

20. USB connection is impossible.

Connect a properly working handset to the Data/USB cable
that is not recognized. Is it recognized?
Is a communication with the handset established via SPST for
GX30?
Connect to a Data with the USB cable.
Is TP536 at "H"?
Is 5 V or more applied to TP515?
Is Q503 pin 3 at "L"?
Is 3 V or more applied to TP166?
IC106 and IC502 are defective.
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Reinstall the driver and replace the USB cable to connect the
NO
handset.
IC106, IC502, and IC504 are defective.
NO
The signal line from CN502 pin 8 to IC106 pin 90 is short-cir-
NO
cuited with GND. Or R566 is has come off.
NO
CN502 is connected improperly.
NO
Q503 is defective.
NO
IC103 or IC106 is defective.
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