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Aug, 1997
1. LCD & LED test
Press the pedal "1". The LCD starts displaying the
test pattern shown in Fig. 1. Verify that the segments
are turned on.
Press a key and verify that the 7-seg LED and the
pedal LEDs are turned on in the order shown in Fig.
2.
2. Switch test
Press a key and the LCD will read "SW1".
Press the keys in the order shown in Fig. 3 and verify
that pressed key is represented on the LCD.
The test stops upon detecting a defective key and
won't proceed to the next key. Take a corrective
action and return to the step 1.
When the test is successful, the test program
proceeds to the step 3. DSP test.
3. DSP test
The test program automatically starts the test step 3 -
1. after completion of the step 2.
3 - 1. Initialization
When the unit is initialized, the program goes to the
step 3 - .2. Otherwise, it displays "ERROR 1" and
jumps to the step 4.
3 - 2. Internal RAM test
The program writes the test data into and reads out
from the internal RAM and then goes to the step 3 - 3.
If error, it displays "ERROR 2" and jumps to the step
4.
3 - 3. External RAM test
The program writes the test data into and reads out
from the external RAM and then goes to the step 4.
If error, it displays "ERROR 3" and goes to the step 4.
4. Output frequency response test
The LCD displays "TEST 1". Sine waves of 20 Hz - 1
kHz - 5 kHz - 15 kHz - 20 Hz from DSP are sent to
OUTPUT sockets at
0.8 sec.
interval.
Connect a noise meter to OUTPUT R. Set the meter
to "FLAT" and check the readings against the table
below.
Connect a noise meter to OUTPUT L (with the blank
plug in R) and check the readings.
The difference in readings between R and L must be
within 1 dBm.
Monitor OUTPUTs R and L and PHONES R and L in
that order on the oscilloscope and make sure they are
look like the waveforms shown in Fig. 4.
Frequency
Level
20 Hz
-20 dBm
1 dBm
1 kHz
-20 dBm
1 dBm
5 kHz
-20 dBm
1 dBm
15 kHz
-20 dBm
1 dBm
To go to the step 5, press VALUE + key.
5. Output stage muting test
The LCD displays "TEST 2". A 1 kHz sine wave from
DSP is sent to OUTPUT sockets at 0.5 sec. interval.
In the similar way as in the step 4 above, connect the
noise meter or scope to OUTPUT R and then L (with
the blank plug in R)
and check the readings. The difference in readings
between R and L must be within 1 dBm.
Monitor OUTPUTs R and L and PHONES R and L in
that order on the oscilloscope and make sure they are
look like
the waveforms shown in Fig. 5.
To go to the step 6, press VALUE + key.
To return back to the step 4, press VALUE - key.
6. OD and DS circuit test
The LCD displays "TEST 3". A 200 Hz square wave
from DSP is sent to OUTPUTs at 0.8 sec. interval at
four different levels.
Monitor the outputs by first connecting the scope to
OUTPUT R and then L (with the blank plug in R) and
make sure that
the waveforms look like the ones shown in Fig. 6.
To go to the step 7, press VALUE + key.
To return back to the step 5, press VALUE - key.
7. OD and DS gain test
The LCD displays "TEST 4". A 200 Hz sine wave from
DSP is sent to OUTPUTs at an 0.8 sec. interval at
four different levels.
Monitor the outputs by first connecting the scope to
OUTPUT R and then L (with the blank plug in R) and
make sure that
the waveforms look like the ones shown in Fig. 7.
To go to the step 8, press VALUE + key.
To return back to the step 6, press VALUE - key.
8. Input frequency response test
The LCD displays "TEST 5". Apply a square wave of
200 Hz, 200 mV to INPUTs.
Monitor the outputs by first connecting the scope to
OUTPUT R and then L (with the blank plug in R) and
make sure that
the waveform looks like the one shown in Fig. 8.
To go to the step 9, press VALUE + key.
To return back to the step 7, press VALUE - key.
9. AUX circuit test
The LCD displays "TEST 6". Apply a square wave of
200 Hz, 200 mV to AUX INP.
The input signal is modified into three waveforms
which are sent to OUTPUTs at an 0.5 sec. interval.
Monitor the outputs by first connecting the scope to
OUTPUT R and then L (with the blank plug in R) and
make sure that
the waveforms look like the ones shown in Fig. 9.
To go to the step 10, press VALUE + key.
To return back to the step 8, press VALUE - key.
10. Residual and shock noises
The LCD displays "TEST 7". Short-circuit the inputs
(e.g. insert a short circuit plug into INPUT and AUX
IN).
Set the noise meter to "JIS-A" or "IHF" and connect it
first to OUTPUT R and then L (with the blank plug in
R) and make sure that the readings are -88.0 dBm or
below. Also verify that difference in noise level
between channels is 1 dBm or less.
ME-30
9
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