580EX II eTTL full power using E-TTL FLASH Off Camera Cord

[JeepDaddy]

Using a 5D Mk III with 580EX II.  On the hot shoe, eTTL works fine. Can access camera menu fine.  When I attach eTTL flash off camera cord to get the speedlite off camera, only full power works, and compensation does not work at all.  Full power only and can't access settings in camera menu.  When I do the same with 430EX II everything works fine on and off camera with the same brand new cord and menu is accessible and settings can be changed.  

Any idea what it could be?

[kvbarkley]

Are you using a Canon cord? Which one? Does it have the extra 4 pins to connect?

[JeepDaddy]

Its not a Canon cord, it's Chinese. I think it is a combination of low quality cord and unreliable contacts on Canons old speedlites. After I posted this question and had a cup of coffee I tried it again and like magic it started working. I swapped out the speedlites and the 430 wouldn't work but after sliding it on and off several times it worked.

I don't use my speedlites very often but every time I do it seems that I have connection problems with everything I use them on including the hot shoe. I have ETTL triggers that I seem to always have the same problem with.

Maybe someone can suggest a way to make the contacts more reliable?

[kvbarkley]

You can clean them with an eraser.

[RobertTheFat · Accepted solution]

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@JeepDaddy wrote:
Its not a Canon cord, it's Chinese. I think it is a combination of low quality cord and unreliable contacts on Canons old speedlites. After I posted this question and had a cup of coffee I tried it again and like magic it started working. I swapped out the speedlites and the 430 wouldn't work but after sliding it on and off several times it worked.

I don't use my speedlites very often but every time I do it seems that I have connection problems with everything I use them on including the hot shoe. I have ETTL triggers that I seem to always have the same problem with.

Maybe someone can suggest a way to make the contacts more reliable?

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The no-brainer is to try a Canon cord. Although bad contacts on the speedlites is a possibility, the fact that both of them fail sporadically suggests that the cord is at fault. And since you rarely use the speedlites, you probably haven't given the contacts time to wear out.