Alto DPA 1500, Service Manual

Page: 19 / 48

5. Test Procedure & Test Result
DPA900/1500 TEST PROCEDURE
DSP Test
Instruments
1. DMM
2. Audio Analyze unit (VP-7724)
3. Oscillograph
4. PC with RS232 port
Test Procedure
Step1: Visual check
Visually check if the cosmetic of the amplifier and assembly are OK.
Step2: Set up
z
Turn off power
z
Set the output sine wave signal of the VP-7724 is 0.775V(0dB)/1KHz, then connect output
of VP-7724 with input of CH1 of amplifier.
z
Connect the DMM with output of CH1 of amplifier
z
Connect the CH1 of oscillograph with CH1 of amplifier, connect the CH2 of oscillograph
with CH2 of amplifier
z
Connect the 4 Ohm load with CH1 and CH2 of amplifier respectively.
z
Turn the volume knob counter clockwise fully.
Step 3: Power supply test
z
Plug the amplifier into mains, turn on the amplifier
z
Make sure all the voltage values are correct, then turn off power.
Step 4: DSP Test
4.1 press the “ENTER” and “SEL” at the same time. The unit will enter the test modal and
check as following:
a.
All LEDs will light up in sequence.
b. The display will show “8.8” .
4.2 Press the “ENTER” and “SEL” at the same time.
a. Press “UP”, the display will show “1”.
b. Press “DOWN”, the display will show “2”.
c. Press “ENTER”, the display will show “3”.
d. Press “SEL”, the display will show “4”.
Step5: Test EEPROM
1.
Press “ENTER” and “SEL” again, the LED (HUM CANCEL) should be light up. After wait
about 50 seconds, check as following:
a. If the display show “01” , the test is ok
b. If the display show “E1”, the test fails.
18