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Canon 600EX II-RT drops link- HELP!


Scenarios I have tried: 


Using Canon Transmitter ST-E3-RT as the master and (2) 600 EX II-RTs as slaves.

Using A 600EX as master and B 600EX as slave.

Using B 600EX as master and A 600EX as slave. 


I get the same result of the slave dropping link. The time varies. Sometimes it drops link in 4 mins, sometimes 10mins, sometimes 20 or more minutes. The only way to relink them is by turning everything off and back on.


All channels are the same. Yes, I have scanned for the best connection as well as every other channel and AUTO.

All IDs are the same. 


Not near a wifi-router or airport, I'm in a row home in Philadelphia. 


Using NiMh rechargeables and using freshly charged batteries for every test. Batteries are about 2 years old. 

I have spoken to 2 Canon service reps and neither of them has any idea what the problem is. I really don't have the money to spend on sending everything in for "repair". 


Any help is greatly appreciated, thanks!





Sadly I couldn't resolve the issue and Canon insisted they couldn't find a problem. I ended up buying new flashes - not an ideal outcome! 

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193 REPLIES 193

A firmware issue with the Canon or other flashes mentioned here? Did it resolve the issue for you? Do you have a link you can share? Thanks!

A firmware issue with the Godox receiver and transceiver not connecting to the R5 or R6; it appears to have been resolved according to comments. I am waiting for them to arrive to test but here's a link:

No! The problem doesn't resolve. Canon, Where are you?

I think everyone should get a refund


I updated the firmware on both of my flashes and had the same issue after I did.  

I did the same and it funny help

What flashes worked for you eventually?

This shouldn't be marked "solved."  It might give Canon the wrong idea.

So I have come to the conclusion that it is something inside of my house that is causing interference with the trigger. If I take the setup to a park or my job then they work great will stay linked until the battery dies but but at my house it only last 5 minutes before the connection is lost. I have tried to narrow it down to find out what the culprit is but I cannot. For now I am using Godox X2 trigger and receivers. With the 600 speedlites it works flawlessly but the Godox receiver on the EL-1 speedlite it is a dumb trigger so  You cannot change settings from the transmitter but it will fire if you set them manually. I encourage others to try shooting in a park or secluded location to see if it yields the same results

click here to view the press release