1. Set both the [JOIN] switches to the OFF position
2. Set all 3 [LEVEL] controls to maximum
3. Monitor [AC OUT] on Channel 1
4. Patch a 500Hz 5VAC p-p triangle wave in to [INPUT 1]
5. Adjust P101 for a 5Vp-p output
6. Monitor [AC OUT] on Channel 2
7. Patch a 500Hz 5VAC p-p triangle wave in to [INPUT 2]
8. Adjust P201 for a 5Vp-p output
9. Monitor [AC OUT] on Channel 3
10. Patch a 500Hz 5VAC p-p triangle wave in to [INPUT 3]
11. Adjust P3201 for a 5Vp-p output

If you do not have an oscilloscope then a multimeter set to AC Volts can be used, you may want to use a lower frequency triangle wave (such as 100Hz).