Roland HandSonic HPD-20 Service Notes page 24

Sep. 2013
15. MIX IN
fig.test-23.eps
* Look out for the big sound.
* If possible, use an oscilloscope to verify that the waveform shows no distortion or
abnormal oscillation.
1.
Connect the oscilloscope to the MIX IN jack.
2.
Output the signals like the following from the oscilloscope.
(Example)
L: 880-Hz sine wave at 6 V
R: 440-Hz sine wave at 6 V
* OUTPUT on the HPD-20 shows no distortion up to maximum input of 8.4 V.
3.
Adjust the VOLUME control to maximum, and verify that sound is heard
from the monitor speakers. At the same time, verify that no artifacts or
abnormal noise are heard.
* Distortion might occur at the monitor speakers because of the high output level
at OUTPUT on the HPD-20. If necessary, lower the VOLUME control on the
HPD-20 and verify that no artifacts or abnormal noise are heard.
4.
Slowly turn the VOLUME control counterclockwise, and verify that the
sound level is gradually lowered.
5.
Change the settings on the oscilloscope.
L: 880-Hz sine wave at 1.4±0.2 V
R: 440-Hz sine wave at 1.4±0.2 V
6.
Connect the headphones to the PHONES jack.
7.
Adjust the PHONES VOLUME control to maximum, and verify that
sound is heard through the headphones. At the same time, verify that no
artifacts or abnormal noise are heard.
8.
Slowly turn the PHONES VOLUME control counterclockwise, and verify
that the sound level is gradually lowered.
9.
Disconnect the oscilloscope and adjust the VOLUME and PHONES
VOLUME controls to maximum.
10. Press F3 (NEXT) to advance to the next test item.
16. OUTPUT
fig.test-24.eps
* Look out for the big sound.
* If possible, use an oscilloscope to verify that the waveform shows no distortion or
abnormal oscillation.
1.
A 500-Hz sine wave is output from the OUTPUT L/MONO jack and a
1,000-Hz sine wave is output from the R jack. Verify that sound is heard
from the monitor speakers. At the same time, verify that no artifacts or
abnormal noise are heard.
* Distortion might occur at the monitor speakers because of the high output level
at OUTPUT on the HPD-20. If necessary, lower the VOLUME control on the
HPD-20 and verify that no artifacts or abnormal noise are heard.
2.
Press F3 (NEXT) to advance to the next test item.
24
17. PHONES
fig.test-25.eps
* Look out for the big sound.
* If possible, use an oscilloscope to verify that the waveform shows no distortion or
abnormal oscillation.
1.
A 440-Hz sine wave is output from the L channel of the PHONES jack
and an 880-Hz sine wave is output from the R channel of the PHONES
jack. Connect the headphones to the PHONES jack and verify that sound
is heard. At the same time, verify that no artifacts or abnormal noise are
heard.
2.
Press F3 (NEXT) to advance to the next test item.
18. FACTORY RESET
fig.test-26.eps
* All user data are lost when a factory reset is performed. Make a backup
beforehand. (Refer to Data Backup and Restore Operations (p. 18).)
1.
Press F3 (EXEC).
The factory reset is executed, and a display like the one shown below
appears.
fig.test-27.eps
2.
Press and hold to turn off the power.
This ends the Test Mode.
HPD-20