AUSTRALIAN MONITOR AMIS250 Series, Руководство по обслуживанию

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TEST PROCEDURE MODEL - AMIS 250 (US)
1. Perform physical inspection (Visual Inspection stage).
1.1
Check:
•
All screws for tightness (esp. bridge rectifier and transistor bolts),
•
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
2. Set up amplifier for test :
2.1
Check :
•
AC fuses (8A), 20mm
•
DC fuses (10A), 20mm
•
2.2 Connect amplifier to :
•
Variac (0 VAC),
•
Signal generator (mic1, no signal),
•
Resistive load ( 4
Ω
on 4
Ω
terminal ).
•
Connect 24V DC supply externally for the relay on amplifier PCB. (Optional test for 24V DC
operation)
2.3 Reset controls :
•
Volume controls to minimum,
•
Bass/treble control to center,
•
R33 & R34 (Bias adjust pots) Amplifier PCB fully anticlockwise.
3 Power up :
3.1 Turn on the power switch and adjust the variac voltage to 115VAC . Watch current meter for
excess current draw. Current should not exceed 0.5A.
3.2 Check DC power supply at the fuses, the measurement should be approximately. 40V (
±
1.5V)
3.3 Check DC voltage on the mixer board, the measurement should be approximately. 15V (
±
0.5V).
3.4 Check 1/2 VCC on mixer board, the measurement should be 8VDC (
±
0.5).
3.5 Measure the DC voltages on the IC’s of the mixer & input PCB's, Pin 8, 15V (+5%), Pin 4 0V
(+100mV),
Pin l, 8V (
±
5%) but on power it should be P8 18V (
±
5%) other remain same.
3.6 Put a multimeter across R47, the meter should read 0.3 mV (
±
5%). Slowly adjust the preset
R 33 so that you measure 2.5mVin addition to the base reading
3.7 Repeat 3.7 for R55 adjusting preset R34.