Mar. 2008 MT-90U Speaker Test 2. Verify that the built-in speaker does not produce a large amount of noise when the power is switched on. 1. Adjust Volume to maximum and switch on the power. 3. Press [ ] to play the built-in demo song, and verify that the music playback from the built-in speaker is free of distortion. 4. Operate the Volume control and verify that the volume level changes smoothly. 5. Shake the unit from front to back and from side to side, and verify that music can be played back without interruption or sound drop-out. Headphones Test 1. While continuing to play back the demo song, connect the headphones. 2. Verify that the built-in speaker stops producing sound. 3.
Verify that the music is played back through the headphones without distortion. 4. Operate the Volume control and verify that the volume level changes smoothly. 5. Switch off the power, wait 5 seconds, then switch the power on again. 6. Verify that the headphones do not produce a large amount of noise when the power is switched on. External Speaker Test 1. Connect the external speaker to the Output jack. 2. Play back the demo song and verify that sound is heard from both the built-in speaker and the external speaker. 3. Set the Speaker switch on the rear panel to Off . 4. Verify that the built-in speaker stops producing sound. 5.
Verify that the music is played back through the external speaker without distortion. 6. Operate the Volume control and verify that the volume level changes smoothly. 7. Switch off the power, wait 5 seconds, then switch the power on again. 8. Verify that the external speaker does not produce a large amount of noise when the power is switched on. 9. Disconnect the external speaker and set the Speaker switch to On . 10. Connect the USB memory device containing the MP3 file to the USB connector on the front panel. 11. While playing back the MP3 file, shake the unit from front to back and from side to side, and verify that no interruption or drop-out of the sound occurs. 21