Canon Speedlite 600 EX-RT User Manual (en, zh)

Troubleshooting Guide
Radio Transmission Wireless Shooting
When using a Speedlite 600EX (without radio transmission function), 
wireless shooting using radio transmission is not available. Use optical 
transmission wireless shooting.
Set the master unit to <'> <M> and set the slave unit to <'> 
<x> (p.52).
Set the transmission channels and wireless radio IDs of the master unit 
and slave unit to the same numbers (p.52 - 54).
Check that the slave unit is within the transmission range of the master 
unit (p.48).
The camera’s built-in flash cannot be used as the master unit in radio 
transmission wireless shooting.
Run the channel scan and set the channel with the best radio reception 
signal (p.54).
Position the slave unit in clear view of the master unit, without obstacles 
between them.
Face the slave unit’s front toward the master unit.
When using autoflash shooting with three firing groups A, B and C, do 
not fire with firing group C pointed toward the main subject (p.63).
When shooting with a different flash mode setting for each firing group, 
do not fire with multiple firing groups set to <a> or </> 
pointed toward the main subject (p.67).
Wireless shooting does not work.
The slave unit does not fire.
The slave unit does not fire or unexpectedly fires at full output.
Pictures are overexposed.