Test Procedure & Test Result - Alto Dragonfly PM-12 Service Manual

7. Test Procedure
1. Test equipment
(1) AP (Audio precision)
(2) Dual-track oscilloscope
(3) Voltage meter
(4) Load
2. Equipment setting
(1) AP Output: 0dBu 1KHz sine wave, load out 600Ω Bal-Float or 600Ω BNC-Unbalanced
(2) AP Output: 15dBu 1KHz sine wave, load 600Ω BNC-Unbalanced.
(3) AP Output: 4dBu 1KHz sine wave, Load 600Ω BNC-Unbalanced.
3. Appearance inspection
Check the appearance of the unit, the potentiometer knob, buttons and faders shall be operated
smoothly.
4. Function test:
(1) After visual check, make sure that the hot line of LAMP and case is not short, it short please don't turn
on the power switch, or it will damage the unit.
(2) Connect the proper AC power supply and turn the main power switch on, the power indicator shall be
lit in green. The fan will start in 4 seconds. If there is no abnormal flicking of any indicators, it indicates
the unit power is normal.
(3) Then turn on the PHANTOM switch and its indicator shall be lit in red. Using voltage meter to
measure the voltage between 2 & 3 pins of each MIC (MIC1, MIC2) input socket and the phantom
voltage shall be 46(+/- 3V). Now turn off the PHANTOM switch.( Note: this switch shall be off during
following tests or the unit may be damaged.)
(4) Turn off PHANTOM switch, measure the voltage of LAMP and it is DC12V (+/-2V)
(5) Set all TRIM, LEVEL, EQ and AUX knobs in zero position, PAN in left and all buttons off.
(6) Connect balanced 0Db input to MIC1 TO MIC8 independently, the respective SG/pea LED will lit in
green. Press MAINL-R and MAIN MIX of CONTROL ROOM SOURCE, and measure the balanced
output of MAIN MIX OUTPUT while PAN knob set in either left or right, the measurement shall be
0dBu (+/-2dBu) THD+N<0.10%. Press MAIN OUTPUT LEVEL button, the measurement of balanced
output will be –30dBu(+/-2dBu) THD+N<0.10%. And meantime, the measurement of unbalanced
output of MAIN L-R is -6dBu(+/-2dBu) THD+N<0.10%, the measurement of DIRECT OUT (1-4) is
0dBu (+/-2dBu) THD+N<0.10%, and the measurement of MONO output is 0dBu (+/-2dBu)
THD+N<0.10%. adjust the LEVEL of mono channel, the output will change dependently. Press MUTE
button of each channel. The respective indicator on channel will be lit in red, and there is no output on
MAIN MIX OUTPUT.
(7) Insert an open stereo plug in CHANNEL INSERT (CH1~8), then input a signal into this particular
channel, and there will be no output on MAIN MIX OUTPUT. If you insert two open stereo plug into
MAIN INSERT L-R, it will be same.
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