Roland ME-25 - Signal Conversion and Performance Checks; A;D, AUX Input, Clipping, and Noise Tests; USB and Battery Operation Tests

17
Feb. 2010 ME-25
6. A/D Check
1. Verify that Ad is shown on the 7-segment LED display.
fig.test6-1.eps
2. On the oscilloscope, set Channel 1 to 0.5 V/div, Channel 2 to 0.5 V/div,
and Time to 1.0 ms/div.
3. On the oscillator, make the settings for output of 200 Hz, 50 mVp-p, and
a rectangular wave, and input this to INPUT.
4. Verify that the OUTPUT L, R output values are between 900 and 1,000
mVp-p.
fig.test6-2.eps
5. Change the input to INPUT from the oscillator to a 47kΩ dummy resistor.
6. On the oscilloscope, set Channel 1 to 0.2 V/div, Channel 2 to 0.2 V/div,
and Time to 1.0 ms/div.
7. On the oscillator, make the settings for output of 200 Hz, 200 mVp-p, and
a rectangular wave, and input this to AUX INPUT.
8. Verify that the OUTPUT L, R output values are between 450 and 550
mVp-p.
fig.test6-3.eps
9. Detach the plug from AUX IN jack, connect the monitor speakers to
OUTPUT L, R, and verify that no sound is heard.
10. Verify that no abnormal noise is heard even when vibration is applied.
11. Press [EXIT] to move to the next test.
7. Clip Check
1. Verify that A.d. is shown on the 7-segment LED display.
fig.test7-1.eps
2. Change the input to INPUT from the 47kΩ dummy resistor to the
oscillator.
3. On the oscilloscope, set Channel 1 to 2.0 V/div, Channel 2 to 2.0 V/div,
and Time to 1.0 ms/div.
4. On the oscillator, make the settings for output of 200 Hz, 4.0 Vp-p, and a
sine wave, and input this to INPUT.
5. Verify that the OUTPUT L, R waveforms are not clipped.
fig.test7-2.eps
6. Press [EXIT] to move to the next test.
8. Residual Noise Check
1. Verify that AF is shown on the 7-segment LED display.
fig.test8-1.eps
2. Change the input to INPUT from the oscillator to the 47kΩ dummy
resistor.
3. Verify that the noise levels for OUTPUT L, R and PHONES L, R are -88
dBu (DIN audio) or less, or -91 dBu (JIS-A) or less.
4. Press [EXIT].
The message Fn appears on the 7-segment LED display, and testing ends.
fig.test8-2.eps
5. Detach the plug from INPUT Jack to switch off the power.
9. USB Check
1. Connect the ME-25 and the computer using a USB cable.
2. Start the ME-25 in the normal operation mode and verify that the
computer detects the ME-25.
From the Start menu, select Settings, then Control Panel, then Sounds
and Audio Devices. At the Audio tab, make sure the ME-25 can be
selected.
10. Battery Operation Check
1. Detach the connected AC adaptor.
2. Insert batteries into the battery compartment, then insert a plug into
INPUT jack to switch on the power.
3. Verify that the 7-segment LED display lights up.
If normal operation can be verified, the test results are considered to be
OK (passed).
* If the 7-segment LED display is dark, check the battery voltage.