Step 7: Knobs
Tighten all the nuts on the pots using a socket or wrench.
Push on the 5 knobs.
Step 8: Test and tweak the trim-pot
Plug the unit into an SCM using the ribbon cable. Make sure the red stripe is towards the white box on
both the SCM and the SCMBO (see the SCMBO manual for details).
Never connect an SCM Breakout directly to the power rail.
To calibrate the unit, you must adjust the trim pot so that you have a complete range of rotation.
1. Run a fast clock into the SCM
2. Turn the trim-pot fully clockwise using a small screwdriver.
3. Turn the Rotate knob fully up/clockwise, PW to the center, and all other knobs fully
down/counter-clockwise. Flip both switches to the right.
4. Slowly turn the trim-pot counter-clockwise, watching which light is blinking the slowest (at the
same speed as the input clock). The slowest light should start as S8/x8 or perhaps S6, and move
upwards as you turn the trim-pot.
5. Stop turning the trim-pot just at the point when Jack x2 is blinking the slowest. Don't turn the
trim pot any more than necessary to make Jack x2 the slowest. You now should be able to get
any light to be the slowest just by turning the Rotate knob: this is a complete range of rotation.
6. Optional: Calibrate the unit for a specific pulse-width instead of complete rotation.
◦
Turn PW to the center position (detent), and the other knobs to any position you
want. The jacks should be outputting pulse waves that are slightly longer than 50%
high and slightly shorter than 50% low.
◦
Turning the trimpot clockwise will bring the ratio closer to 50/50 with PW at the
detent, but you may no longer have a complete range of rotation using the Rotate
knob (you will always have a complete range using CV, the trim-pot does not effect
the CV inputs)
◦
If your needs require you to very often have a precise 50% duty cycle pulse wave (or
any particular duty cycle), you may wish to calibrate the trim-pot to get this with PW
at the center detent. Doing so might sacrifice having a complete range of parameters
using only the knobs (however, the unit will still have it's full range if CV is
applied).
Step 9: Patch it up!
You're done! Test out all the features, read the manual, and have fun!
