20-Watt AC/Mobile PA  (320-2041)    Troubleshooting    Faxback Doc. # 15377
Amplifier

The MPA-31 Amplifier should require very little maintenance.  If you do
have problems, refer to this chart for possible solutions.  If you cannot
solve the problem, contact your local Radio Shack Store for assistance.

Nothing works   If you are using AC power.
                - Check the AC fuse (on the back panel).  If the fuse is
                  blown, replace it with a 2-amp, 250-Volt fuse (see
                  "Replacing the Amplifier's Fuse".
                - Check to make sure the Ac outlet has power.

                - Check the power connections to the rest of the system
                  (turntable, CD player, tuner, etc.)

                  If you are using vehicle battery power:

                - Check the DC cable's in-line fuse.  If the fuse is
                  blown, replace it with a 4-Amp, 125-Volt fuse (see
                  "Replacing the DC Cable's Fuse".
                - Check to make sure the vehicle battery has power.
                - Check to make sure the DC adapter is properly connected.

                  Make sure none of the speaker wiring, microphone cables,
                  or other connecting cables are defective.

No signal from    Check the control setting.
an audio input    Check the connections between the amplifier and the
source            input source.

                  Make sure a microphone is not defective.

Hum from PHONO    Connect the turntable's ground wire (usually black or
                  green) to one of the GND screws on the back of the
                  amplifier.

Hum from other    Make sure there are no low level inputs connected to the
inputs            PHONO/AUX.CD jack.

Feedback          Move the microphone further away from the output
"squeals"         speakers or use a directional microphone.

                  Adjust the TONE controls if necessary.

Amplifier         Be sure you have provided adequate ventilation to the
overheats         amplifier.

Weak speaker      Be sure you correctly calculated the total speaker
response          impedance.


(br/all-05/30/95)