MPA-200 Stereo PA  (320-3003)      Troubleshooting     Faxback Doc. # 14631
Amplifier

Symptom                        Cause                               Remedy

No Output.             Faulty AC power cord.                        Replace
                       Defective power switch.                      Replace
                       Broken wire in the power transformer.        Replace
                       Fuse F1 6A is open.                          Replace

Main output works      Poor contact in phone output jack     Repair/Replace
but headphones         Defective R134 and R234                      Replace
does not work.

No output when a       Defective protector circuit IC1              Replace
signal is applied      Defective speaker switch SW2                 Replace
to the input           Defective volume VR101 and VR201             Replace
terminal

VU meter does          Poor contact in VU meter                     Replace
not work.              Defective SW3                                Replace
                       Defective D104,D105,D204,and D205            Replace

Sound is               Speakers are out of phase (+-).        Reconnect and
distrorted with                                               be sure the
little bass                                                   phases of the
and unnatural                                                 speaker wires
playback                                                      are matched
response

A humming sound     Either the pin plug, cord, or shield        Replace the
interfers while     is not connected properly or the cord       shield or 
playing record.     is the cord is improperly plugged in.       plug in the
                                                                cord.
                    The ground wire is not connected            Connect the
                    adequately.                                 ground to
                                                                the
                                                                turntable.
A howling sound     Either the record player and speaker        Change
occurs when the     system are too close together or they       location of
volume is in-       are unsteady.                               the record
creased while                                                   player and
playing a                                                       speaker.
record                                                          Place the 
                                                                turntable
                                                                on a sturdy
                                                                table or
                                                                shelf.


(SP/all-04/20/95)