Roland Boss RC-20XL Service Notes page 16

Sep.2004
6.DA check
• Once again check the output wavwform at the point that "5.GUIDE
volume check" is completed, to check the DC leakage and level.In the
following cases, the result is NG.
Excessive level NG
↑
2.4
Vpp
↓
(0.5V/DIV, 1mS/DIV)
+DC NG(Asymmetrical:the upper
and lower sides)
(0.5V/DIV, 1mS/DIV)
7.OUTPUT check
.Set the INST volume and MIC volume to 'minimum'.
.Set the PHRASE SELECT volume to the 'REVERSE' are lit.
.Verify that the output waveform is as shown in the diagram.
fig.AUX+DA_40
(0.5V/DIV, 1mS/DIV)
The waveform will change slightly depending on the inaccuracy of the input
function.
8.INST volume check
• Set the PHRASE SELECT volume to the '3' position.
• Verify that "REVERSE" is dark and "TAP TEMPO" is lit red.
• Set the INST volume to 'minimum,' and slowly move it to 'maximum.'
• Verify that the waveform increases smoothly.
• Verify that that when the INST volume is at maximum, the waveform is
the same as shown in the diagram.
16
Insufficient level NG
↑
2.0
Vpp
↓
(0.5V/DIV, 1mS/DIV)
-DC NG(Asymmetrical:the upper
and lower sides)
(0.5V/DIV, 1mS/DIV)
fig.INST_40
(0.5V/DIV, 1mS/DIV)
1.2Vp-p 0.2Vp-p
9.MIC volume check
• Set the PHRASE SELECT volume to the '4' position.
• Verify that "TAP TEMPO" changes from red to green.
• Set the MIC volume to minimum, and gradually move it to maximum.
• Verify that the waveform increases smoothly.
• Rotate the MIC volume control and confirm that "PEAK" lights as shown
in the figure.
fig.p-mic_40
Lighting Start
Full lighting
• Confirm that the same waveform as in the figure is produced when the
MIC volume control is at maximum.
fig.MIC_40
(0.5V/DIV, 1mS/DIV)
• Connect a noise meter to OUTPUT, and verify that the reading is in the
range of -1.0 dBm 1.5 dBm.
10.MUTE check
• Set the PHRASE SELECT volume to the '5' position.
• Verify that "TAP TEMPO" is dark and "LOOP QUANTIZE" is lit.
• Verify that the output waveform is the same as the waveform shown in
the diagram.
fig.MIC-Mut_40
(0.5V/DIV, 1mS/DIV)
• Connect a noise meter to OUTPUT, and verify that the reading is in the
range of -22.0 dBm 1.5 dBm.