Alto Dragonfly PM-12 Service Manual page 69

7. Noise test:
Connect high quality speakers with PM12, press MAIN MIX of CTRL ROOM SOURCE, set PHONES
knob at maximum. Press MAIN L-R buttons on each channel, all faders up to maximum, then turn the
TRIM knob of each channel to verify there is no abnormal noise.
8. Power test:
Connect a 4 ohm load and set the AP's Watts column as 4 ohm.
(1) Adjust MAIN MIX LEVEL to minimum, input a +15dBu 1KHz Sine wave (load out 600Ω BNC-Unbal) to
LINE 1, press the MAIN L-R button on this channel, the output power is 100W (+/-20W), the response
curve is as below.
(2) Reduce output to 1W, THD+N<0.30%, the response is as below: (on both left and right channel).
(3) Burn-in test: connect 4 ohm load on left and right channel, single channel output power is 100W(75%),
test for 2H.
9. Connect the unit to high quality amplifier and speaker, there shall be no noise while listening.
10. Setting before shipment: all level controls in minimum, other knobs in center, all switch in off.
11. Done.
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