8-4. BUS MULTIPLEXER CCA 2A2A7A6A7 (cont)
Make adjustments in small increments
to allow readings to stabilize.
If counter indicates frequency
deviation exceeds limits, but is
between 6.71988 and 6.72012 MHz,
adjust U42 (8) as required to obtain
stable, nominal frequency.
After adjustments are complete,
allow 30 minutes for possible drift.
Turn off CB3 on AC control panel.
Turn off CB1 on AC control panel.
The bus multiplexer CCA contains
parts sensitive to electrostatic
discharge (ESD). Use ESD precau-
tionary procedures (para 2-21) when
touching, removing, or inserting
Remove BUS multiplexer CCA/extender
board from electronics drawer
Disconnect CCA from extender board
and reinstall CCA in backplane.
Slide electronics drawer fully into
Reinstall, securing screws (1),
lockwashers (2), and flat washers
If system is to be operated after
adjustment, energize CB1. Wait 10
seconds, then energize CB3.