Sharp GX15 Service Manual page 54

GX15
2. Voice transmission/recording is impossible.
Phone (Handset)
Replace the microphone.
Is the problem solved?
Is 1.2 - 2.1 V applied to both ends of C101?
Is approx. 1.7 V applied to IC103 pin 80?
Is 0.5 V or more applied to R101 (IC103 pin 9 side)?
Is 0.5 V or more applied to JK101 pin 5?
Is 0.5 V or more applied to JK101 pin 3?
Is 0.5 V or more applied to TP120?
Is 2.4 - 2.6 V applied to TP176?
Is 2.4 - 2.6 V applied to R115 (IC103 pin 76 side)?
Replace C121A or C133. Is the problem solved?
IC103 and IC106 are defective.
CONFIDENTIAL
NO
YES
YES
NO
NO
NO
NO
NO
NO
NO
The built-in microphone is defective or in a poor contact with
YES
the PWB.
L101, L102, and C101 are defective.
NO
Is 1.2 - 2.1 V applied to TP119?
Is 2.4 - 2.6 V applied to TP176?
NO
Is 2.4 - 2.6 V applied to IC103 pin 76?
NO
IC103 is defective.
NO
Is approx. 1.7 V applied to IC103 pin 96?
NO
R263 and R118 are defec-
tive.
IC103 is defective.
YES
Parts between socket JK101 pin 5 and IC103 pin 9 are defec-
YES
tive.
YES
Socket JK101 is defective.
YES
Parts between socket JK101 pin 3 and TP120 are defective.
YES
R122 is defective.
YES
R115 is defective. (Headset mode is set.)
YES
C121A or C133 is defective.
2 – 46
YES
NO
YES
R125 is defective.
YES
R115 and C108 are defec-
tive.
YES
IC103 is defective.