Boss RE-20 COSM Service Notes page 22

May, 2007
10. DSP Throughput Waveform Check
Press the right pedal to perform the DSP throughput (output) waveform check.
* The leftmost and center Virtual Tape Display LEDs light up.
1.
Verify the output waveforms from OUTPUT A (MONO) and OUTPUT B.
2.
Verify that the waveform shown below is output.
fig.check012.eps_48
500 mV/DIV, 1 ms/DIV
3.
Turn the INPUT VOLUME control (MAX -> MIN -> MAX) and verify the
output waveform.
* Verify that the waveform changes smoothly.
4.
Verify that when the control is set at MIN, the waveform shown below is
output.
fig.check013.eps_48
500 mV/DIV, 1 ms/DIV
5.
After verification, detach all plugs except for the one inserted into INPUT
A (MONO).
6.
Detach the plug inserted into the INPUT jack and switch off the power.
22
11. Residual Noise Test
1.
Set the potentiometers at the positions described below.
• All except MODE SELECTOR and INPUT VOLUME: MAX position
• MODE SELECTOR: REVERB ONLY position
• INPUT VOLUME: MIN position
• DIRECT switch: ON position
2.
Connect 47 kΩ short plugs to both INPUT A (MONO) and INPUT B.
3.
Depressing the left and right pedals and inserting a plug into the INPUT
A/MONO jack makes the PEAK LED light up.
4.
After approximately 2 seconds, the PEAK LED goes dark.
5.
Release the left and right pedals, then within 5 seconds, depress first the
left pedal, then the right pedal to enable residual noise testing.
* Entering the residual noise test makes the three rightmost Virtual Tape
Display LEDs light up.
* The analog bypass signal is output.
6.
Adjust the INPUT VOLUME control to the MAX position.
7.
Measure the output level at OUTPUT A (MONO) and OUTPUT B.
Passing value: -94 dBm or less (JIS A)
8.
Depress the right pedal. (The three leftmost "Virtual Tape Display" LEDs
light up.)
* The DSP throughput signal is output.
9.
Measure the output level at OUTPUT A (MONO) and OUTPUT B.
Passing value: -91 dBm or less (JIS A)
10. Depress the right pedal once to enter the normal mode.
11. Continue by executing the next noise test.
12. Audible Noise Check
From this section and after, inspection is carried out in the normal
performance mode.
1.
Connect 47 kΩ short plugs to both INPUT A (MONO) and INPUT B.
2.
Adjust the INPUT VOLUME control to the MIN position.
3.
Connect the output from OUTPUT A (MONO) and OUTPUT B to a
powered monitor.
4.
Adjust INPUT VOLUME to the MAX position and verify that audio is
silent.
5.
Apply impact to the RE-20 unit and verify that no abnormal noise occurs.
6.
Turn the INPUT VOLUME control from the MIN position to MAX, and
verify that no abnormal noise occurs.
7.
Adjust the INPUT VOLUME control to the MIN position, then detach all
plugs and switch off the power.
13. Battery Operation Check
1.
Detach the connected AC adapter.
2.
After inserting batteries into the battery compartment, insert a plug into
INPUT A (MONO) and switch on the power.
Verify that the PEAK LEVEL LED lights up.
3.
If normal operation can be verified, the test results are considered to be
OK (passed).
* If the PEAK LEVEL LED is dark, check the battery voltage.
This completes the testing.
RE-20