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The delivery of this manual was very fast, less than 8 hours. The manual is very clear and concise, and helped a great deal in the repair and final setup of the Hitachi HMA-G2 Amplifier.
Text excerpt from page 56 (click to view)
GX15
3. No voice is heard from the earpiece.
Phone (Handset) Do keypad tones and melodies sound?
YES
CONFIDENTIAL
NO
Go to the section �Earpiece (for loud speaker) does not work�. (see page 2-50)
Is 0.5 V or more applied to R101 (IC103 pin 9 side)?
NO
YES
IC103 is defective.
Is 0.5 V or more applied to JK101 pin 5?
NO
YES
Parts between socket JK101 pin 5 and IC103 pin 9 are defective.
Is 0.5 V or more applied to JK101 pin 3?
NO
YES
Socket JK101 is defective.
Is 0.5 V or more applied to TP120?
NO
YES
Parts between socket JK101 pin 3 and TP120 are defective.
Is 2.4 - 2.6 V applied to TP176?
NO
YES
R122 is defective.
Is 2.4 - 2.6 V applied to R115 (IC103 pin 76 side)?
NO
YES
R115 is defective. (Hands free kit mode is set.)
IC103 is defective. Hands free kit (Headset) Replace the hands free kit. Is sound produced?
NO
YES
The hands free kit is defective.
Is signal sent to JK101 pin 4?
NO
YES
Socket JK101 is defective, or the hands free kit is in a poor contact with the socket plug.
Is signal sent to TP121?
NO
YES
Parts between socket JK101 pin 4 and TP121 are defective.
Is signal sent to R124 (IC103 pin 60 side)?
NO
YES
Parts between IC103 pin 60 and TP120 are defective.
Disconnect the hands free kit. Is voice heard in phone mode?
YES