How to Lock the OMC.
Turn OFF the OMC length servo (C1:OMC-LSC_GAIN) , and turn off the Integrator (FM1).
Turn ON the OMC length servo.
Scan the OMC_LSC_OUTPUT_OFFSET slider until you lock a 00 field. You have to watch the OMCT camera image to know if you've locked a 00.
Turn on the Integrator (FM1).