Aphex 250 - Test and Nulling Procedures; Test Equipment and Main Board Tests

7.0 TEST AND NULLING PROCEDURES
The listed test procedures require the use of the following test equipment:
1. Audio Analyzer (Sound Technology 1710 or equivalent)
2. Spectrum Analyzer (Tektronics 5L4N or equivalent)
3. Sweep Function generator (B&K 3025 or equivalent)
4. Multimeter (Fluke 77 or equivalent)
5. Oscilloscope (minimum 10MHz bandwidth)
7.1 MAIN AUDIO BOARD
7.1.1 Beginning Setup
1. Make sure all boards are connected.
2. Verify Ax, SOLO, and SPR are all "OFF".
3. Verify RELAY (Bypass) is "OFF".
7.1.2 Input CMRR
1. Set input signal equal to 100Hz at +20dBu, COMMON M ODE.
2. Null the output using VR201 and 101. CMRR should be better than 60 dB.
7.1.3 Output CMRR
l.S et input signal equal to lOOHzat +20dBu, NORMAL MODE.
2. Terminate output with 600 ohms.
3. Adjust VR 102 (202) for null at TP101 (201).
7.1.4 Gain Test
1. Set input signal equal to 100Hz at +20dBu, NORMAL MODE.
2. Check that output level equals +20dBu with 600 ohm load.
3. Raise input until output chips; level should equal +25dBu.
7.1.5 Distortion
l.S et input signal equal to lk H zat +10dBu, NORMAL MODE.
2. Verify output distortion less than .006%.
3. There should be no crossover distortion.
4. Increase input to +20dBu.
Test and Nulling Procedure 7 -1