Yamaha PSR-S770, Service Manual

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50
PSR-S770/PSR-S970
4.■ Other■Inspections
4-1.■ AUX■IN
Take measurement with the Test Program [028: AUX-IN Check] selected.
Check that each terminal output is as shown in the table below when a signal is inputted into AUX IN.
INPUT
■
OUTPUT
PHONES■(33■
W
■load)
L R
AUX IN L: Sine wave (1 kHz, 0 dBu)
AUX IN R: No input
+1.6 ± 2 dBu -56.0 dBu or less
AUX IN L: No input
AUX IN R: Sine wave (1 kHz, 0 dBu)
-56.0 dBu or less +1.6 ± 2 dBu
4-2.■ Noise■Level■Check
1) Do not connect anything to the [AUX IN] and [MIC/GUITAR INPUT] jacks.
2) Connect the level meter (using the JIS-C fi lter) to the L/R [PHONES] and L/R [OUTPUT] jacks.
3) Turn the master volume to the maximum position.
4) Measure the output voltage and confirm that the measured values are within specification as follows:
<PHONES>
L: -90.0 dBu or less
R: -90.0 dBu or less
<OUTPUT>
L: -90.0 dBu or less
R: -90.0 dBu oe less
4-3.■ MIC/GUITAR■INPUT
1) Take measurement with the Test Program [030: MIC Check] selected.
2) Do not connect anything to the [AUX IN] jack.
3) Connect the level meter (using the JIS-C filter) to the L/R [PHONES]. (33 ohms load)
4) Turn the master volume to the maximum position.
5) Set the [MIC GUITAR] switch to “GUITAR” and set the [GAIN] knob to the maximum posision.
6) Apply a 1kHz sine wave -30dBu to the [MIC/GUITAR INPUT] jack via a 100k
W
resistor.
7) Measure the output voltage and confirm that the measured values are within specification as follows:
<PHONES>
L: +0.9 ± 3 dBu
R:
+0.9 ± 3 dBu
8) Set the [MIC GUITAR] switch to “MIC.”
9) Measure the output voltage and confirm that the measured values are within specification as follows:
<PHONES>
L:
–15.6 ± 3 dBu
R:
–15.6 ± 3 dBu
10) Set the [GAIN] knob to the minimum posision.
11) Measure the output voltage and confirm that the measured values are within specification as follows:
<PHONES>
L:
–49.1 ± 3 dBu
R:
–49.1 ± 3 dBu