Alternate FMC - Captain 
FMC Switch (Alternate Action - Illustrated)
Normal:
- ALTN - Opposite FMC supplies EFIS SG
L FMC FAIL
- Select both EHSI range selectors to same position
- Use Right Autopilot
Nav Instrument Source Selector (Rotary Action - as installed)
- Capt FMC L - Left FMC supplies Left and Centre EFIS SG and FCC
- Capt FMC R - Right FMC supplies Left and Centre EFIS SG and FCC
- Capt CDU L - Left CDU supplies Left and Centre EFIS SG