AUSTRALIAN MONITOR AMIS120XL Series, Руководство по обслуживанию

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TEST PROCEDURE MODEL - AMIS 120
1. Perform physical inspection (Visual Inspection stage).
1.1 Check:
•
Earth connection for good contact (XLR GND to AC earth),
•
All wiring points for good contacts (soldering and crimping)
PRETESTING
PRE TESTING SETUP REQUIREMENT
a Oscilloscope.
b Variac.
c Multimeter.
d Load [4
Ω
]
e Signal generator.
.
1.1. Connect amplifier to:
•
Variac (0Vac),
•
Signal generator (mic1, no signal),
•
Resistive load ( 4
Ω
on 4
Ω
terminal ).
1.2. Reset controls:
•
Volume controls to minimum,
•
Bass/treble control to center,
•
Phantom power switch to off,
•
R33 & R34 (Bias adjustment pots) on the amplifier PCB fully anticlockwise.
2. Power up :
3.1 Turn on power switch and adjust voltage to 115VAC/230VAC . Watch current meter for excess
current draw. Current should not exceed 0.5A.
3.2 Check DC power supply at fuses. Should be approx. +34V (
±
1.5V)
3.4 Check DC voltage on mixer board. Should be approx. 15V(
±
0.5V)
3.5 Check 1/2 VCC on mixer board should be 8. VDC (
±
0.5)
3.6 Measure DC voltages on IC of mixer & input PCB's, p8 15V (+5%), p4 0V (+100mV), pl 8V
(
±
5%) but on power it should be P8 18V (
±
5%) other remain same.
3.7
Put a multimeter across R30 the meter should read 1.0mV (
±
5%) then slowly adjust the preset R33 so
that you get 3mV additional to the base reading.
3.8 Repeat 3.7 for R39 adjusting preset R34.
3.9 Un do step 3.1
3. AC Check :
4.1 Set signal generator to 1mV. Turn up Mic1 volume control to full. Watch for irregularities with output.
4.2 Set output to 35V using master volume control. Check voltage across Emitter resistors (on power
devices)
4.3 Voltage should be between 150 – 200mV. Min and max values should be between 33% of the average
value (i.e. min/max=0.5).
4.4 Turn master up to full. Check sensitivity of input. – MIC 1mV (+ 10%) 22V in 4
Ω
load.