<Voice output error>
+12 V DC at 1st and 2nd pins of JP1?
Signal input of 4th pin of U12 is at H level
(+5 V DC)?
Check mute input circuit of I/F board.
Input signal of 3rd and 5th pins of U12 is normal?
Check power supply, vo ice input and voice
input circuit of I/F board.
Signal input at 1st and 7th pins of U12 changes
when voice volume is changed.
Check control PWB and the volume circuit
around U11.
Signal output at 8th, 10th, 11th and 13th pins of
U12 is normal?
Check amplifier circuit around U12.
Check speakers and speaker cables.
• Check connection of JP1 connector.
• Check fuse F1 of Power Jack PWB.
