Troubleshooting - Yamaha M-4 Owner's Manual

TROUBLESHOOTING
Power does not turn on when power plug is inserted into
AC outlet.
Power will not turn on although POWER switch is ON.
Contact an audio serviceman at your nearest Y AMAHA
dealer.
Insufficient connection between control amplifier and
= 5 Check and confirm connection, or operation.
power amplifier, or between power amplifier and speakers.
BALANCE control of the control amplifier has deviated
either to the right, or left side.
No sound produced from the right and left speakers, or
either the right, or left speaker.
Properly re-adjust BALANCE control of control amplifier.
LEVEL control turned down too much. (Turned too far
counterclockwise. }
Turn LEVEL control clockwise.
When the potential of the power amplifier becomes zero,
the relay will be actuated, causing the circuit to be
connected.
Speaker's protective circuit is working because a DC po-
tential not less than 2.4V has generated at the speaker's
output terminal.
Turn off the POWER switch of the power amplifier.
Wait a little while and turn it on again.
Sounds suddenly cease to come out during PLAY.
Contact an audio serviceman at your nearest Y AMAHA
dealer.
Abnormality inside the circuit.
The phases (* and —) of the power amplifier not match-
ing those of the speakers.
Unnatural reproduced sounds with poor bass and instable
Sufficient volume not obtained when VOLUME control
of control amplifier is turned up.
Adjust to proper volume by turning input LEVEL con-
trol clockwise.
Insufficient contact of pin plug. Re-insert pin plug in firm manner.
Earth line of turntable not connected to GND terminal
of control amplifier.
input LEVEL control is turned counterclockwise.
Loud humming generates during program audition.
Connect earth line to GND terminal of control amplifier.