Service manual

GS160/320 Component Removal and Replacement 4-51
Removal
1. Shut down the operating system(s), put the OCP switch in the Off position,
and trip the main circuit breakers on both AC input boxes.
2. Open the rear door(s).
3. Remove the upper H-switch power supply. See Section 4.7.2. The clock
module is now exposed.
4. Unplug all coax cables connected to the module making sure that the QBB
ID labels are secure. (You may want to use needle-nosed pliers for this.)
5. Unplug the ribbon cable that goes to the H-switch module.
6. Unscrew the four Phillips head screws that hold the module in place and
remove it from the H-switch housing.
Replacement
Reverse the steps outlined in the removal procedure. Be sure that the QBB
coax cables get plugged into the correct clock connector – they are color coded
and labeled.
Verification
Power up the system.
Be sure to put the circuit breaker in the on position before you
put the OCP switch in the On position.