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6. Test Procedure
The semi-finished product test procedure
6.1Test Instruments
1.
Power supply 2. Digital voltage meter 3. AP (Audio precision)
4. Oscilloscope 5. Two 8
Ω
(400W) resistors
6.2 Test procedures and specification
a.
Set LIMITER and BRIDGE switches at the position of OFF, turn the VRs of CH1
and CH2 to maximum, then turn on the power switch, the power LED will be
illuminated (blue), OPERATING/PROTECTION LED is illuminated to be red at
first, then become green after 2-5 seconds, the fan will be running. When you use
the solder gun to test the position of R1-3 (R2-3), the fan should be accelerated.
b.
Without any signal input, adjust R1-20, R1-21 (R2-20, R2-21) backwards first,
make sure the arrow is facing to the rear panel, then adjust forwards, make the
arrow is facing to the front panel, then test the DC voltage across the TP1-6 (TP2-6)
and the ground, adjusting R1-16 (R2-16), the voltage of R1-16 (R2-16) should be
138mV
±
2mV.
c.
Connect a load of 4
Ω
to each channel, input the signal of 4dBu , then adjust R1-
20, R1-21 (R2-20, R2-21) , make sure that the crossover distortion reaches its peak.
d.
Turn off the input signal, the standby power consumption should be 75~105W.
e.
Input the signal of 1KHz/3dB to CH1 and CH2, then connect a 4
Ω
load to each
input channel, CH1 and CH2. Each output should be 69.2V, the distortion should
be 1%.
f.
Turn the power switch of the LIMITER to ON position. Set the input to
1KHz/+10dB the clip should be lit up and the signal will not boost.
g.
Use the solder gun to connect R1-50 and R2-50 for about 10 seconds separately.
When the outputs of CH1 and CH2 are cut off, OPERATING/PROTECTION LED
will be illuminated (red).
h.
Press BRIDGE switch, input the signal of 1KHz/4dB to CH1, connect a 8
Ω
load
to the bridge output, the output should be more than 133.5V, the distortion should
be less than 0.7%.