Yamaha A4000, Руководство по обслуживанию

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A5000/A4000
30
91 SCSI TERM SW
Turning on the A5000/A4000 power switch, the test can start after
more than 5 seconds. The voltage can be measured the SCSI connec-
tor for the internal connect and the DM circuit board of the CN9-2
pin (the SCSI signal line). Check the voltage of the switch fills the
following.
TERM SW ON: 2.85 +/- 0.5 V
TERM SW OFF: 0.00 +/- 0.5 V
92 REMAIN NOISE
Insert the appropriate phone plugs into the STEREO OUT L, R,
ASSIGNABLE OUT-L, R, PHONES terminals. Check each output
by using an oscilloscope, an AC voltmeter (with JIS-C filter) and a
distortion factor meter.
The MASTER VOLUME control must be set at maximum for these
checks.
STEREO OUT-L: Remain Noise less than -70 dBm (10 k ohm load)
STEREO OUT-R: Remain Noise less than -70 dBm (10 k ohm load)
ASSIGNABLE OUT-L: Remain Noise less than -70 dBm (10 k ohm load)
ASSIGNABLE OUT-R: Remain Noise less than -70 dBm (10 k ohm load)
PHONES (L): Remain Noise less than -62 dBm (33 ohm load)
PHONES (R): Remain Noise less than -62 dBm (33 ohm load)
93 POWER SUPPLY VOLTAGE
Turning on the A5000/A4000 power switch, test can start after more
than 5 seconds. The voltage can be measured the both terminals of the
capacitor [C36] on the DM circuit board. Check the voltage of the
switch fills the following
Voltage: 5.00 +/- 0.25 V
94 POWER ON/OFF MUTE
Turning on and off check the output of the STEREO OUT-L, R,
PHONES,ASSGNABLE OUT-L, R, ASSIGNABLE OUT1-6 ter-
minals by an oscilloscope.
The MASTER VOLUME control must be set at maximum for these
checks.
Body :
STEREO OUT-L
: less than 200 m Vp-p (10 k ohm load)
STEREO OUT-R : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-L : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-R : less than 200 m Vp-p (10 k ohm load)
PHONES (L)
: less than 500 m Vp-p (33 ohm load)
PHONES (R) : less than 500 m Vp-p (33 ohm load)
IO circuit board
ASSIGNABLE OUT-1 : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-2 : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-3 : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-4 : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-5 : less than 200 m Vp-p (10 k ohm load)
ASSIGNABLE OUT-6 : less than 200 m Vp-p (10 k ohm load)