Yamaha DTXPRESS Service Manual page 21

This test checks the OUTPUT (R) for the specified signal
output level.
Insert the plugs into the OUTPUT (L/MONO and R) jacks.
Set the MASTER volume to maximum and AUX IN
volume to minimum. Use the frequency counter,
oscilloscope, distortion meter and level meter (with flat
filter) to measure frequency, waveform, distortion and
output level.
Check that the AUX IN jack is unplugged and that the
input voltage is less than -90 dBm.
Check points
OUTPUT(R):
50 Hz +/-3 Hz, sine wave, +2.7 +/-2 dBm (10 kohm
lord)
Test End
OK: It proceeds to the next test automatically.
T–44. AUX INPUT
Initial Display
44 AUX INPUT
This test checks the AUX IN signal output to the PHONES
for the specified signal output level.
The sign wave is input from the low frequency oscillation
machine to AUX IN (L). The sine wave to the AUX IN(L)
should be shorted to ground.
Insert the stereo phone plugs into the OUTPUT (L/MONO
and R) jacks. Use the frequency counter, oscilloscope,
distortion meter and level meter (with flat filter) to
measure frequency, waveform, distortion and output level.
Check points
Apply a -2.0 dBm sine wave( 10 kHz, 1 kHz and 50 Hz) to
the AUX IN (L). AUX IN (R) should be shorted to ground.
Set the AUX IN volume to maximum. Make the AUX IN
volume and the mastering volume Maximum.
OUTPUT (L/MONO):
+4.3 +/-2 dBm (10 kohm lord and distortion is less
than 0.3 %) AUX IN (L) should be shorted to
ground. Set the AUX IN volume to maximum.
OUTPUT (R):
+4.3 +/-2 dBm (10 kohm lord and distortion is less
than 0.3 %)
Apply a -2dBm sine wave (10 kHz, 1 kHz and 50 Hz) to
the AUX IN (R). AUX IN (L) should be shorted to ground.
Set the AUX IN volume to maximum.
Test End
OK: It proceeds to the next test automatically.
T–45. 32ch OUT
Initial Display
45 32 ch OUT
Checks that the correct sine wave signals are output from
the unit. The signal from channels 1 to 16 is output from
the left output jack, that from channels 17 to 32 is output
from the right.
Press the [SAVE/ENT.] button. Then the signals are output
16 times ( 0.3 seconds on and 0.1 seconds off ) for all 32
channels.
Set the MASTER volume to maximum.
45 32ch OUT
Lch=XX Rch=XX
XX indicates the sound output channels.
Check points
Check that all 32signals are output.
Check that it is a sine wave with a normal output crimp.
(Lch= 1 kHz, Rch= 700 Hz)
Test End
OK: It proceeds to the next test automatically.
T–46. FACTORY SET
Initial Display
46 FACTORY SET
This test sets parameters back to their factory values.
To initiate this reset, press the [SAVE/ENT.] button.
Test End
Blank
T–47. EXIT
Initial Display
47 EXIT
Exit from test mode.
Press the [SAVE/ENT.] button to exit from TEST mode.
The system responds to the EXIT by executing the normal
power-up sequence. The system will require a few seconds
to enable itself for normal play.
Comments
1. Measure the click noise produced whenever the power
switch is turned on and off and also that produced by
disconnecting the DC adaptor. The click noise level must
not exceed 0.1V-pp at the terminals of
OUTPUT(L/MONO,R).
2. Factory Reset
While depressing the [PAGE-] and [PAGE+] buttons,
turn the power switch on.
DTXPRESS
21