A mystery that might be about 430EX II and Flex TT5

Hello, experienced and wise photographers, I have encountered a problem today when shooting in a wedding, a problem that almost screwed me up. I'm wondering if someone could explain it to me and tell me how to avoid it in future. Here is the story:

I have three 430EX II and one 580EX II. I triggered them all by PW FlexTT5. After about half an hour or maybe an hour, one of the 430EX II didn't work. I checked and found that it's off. I turned it off and then on again. It blinked once and got back to off. I put in new batteries and reconnected it to the FlexTT5 to make sure that the connection was good. But it still didn't work. So, I have to take pictures with the other three Speedlites.

Then, after maybe two hours (with one hour being a break as they moved to another place for reception), another 430EX II died on me in the same way. I changed the batteries again and checked the hotshoe connection. But there was no luck.

When I was home worrying that I might have to use the meager money I earn in the wedding to get them fixed, I tried again and both of them were just working fine. I pressed the Test button on the FlexTT5 and there was flash!

I used 7D and 50D, because I didn't want the trouble to switch the lenses. Instead, I switched the MiniTT1 (with AC3) between the two bodies.

I have thought that maybe it's overheat. However, the second 430EX II died after an hour of break. And the third 430EX II had been working fine (though it's hard to say whether it's giving out the same amount of light as the other two since I had been using auto mode).

(And a side note: the exposure has not been very consistent. But this may be just due to poor skills.)

Where you using manual or ETTL modes?

If the latter, it could be that due to placement and variable subject conditions, those particular flashes were having to work harder than you thought, and putting out full pops causing them to overheat and thermally cut off after a while.

If manual, were all three 430's set to the same power, or were the ones that died first outputting more power than the other one?

there was a documented problem with the PWs where they fried certain models of speedlights when they put the flashes into HSS mode.. I will see if I can find it

lettershop wrote in post #12412209
there was a documented problem with the PWs where they fried certain models of speedlights when they put the flashes into HSS mode.. I will see if I can find it

That research paper found issues with the 580exII.

talbot_sunbeam wrote in post #12412070
Where you using manual or ETTL modes?

If the latter, it could be that due to placement and variable subject conditions, those particular flashes were having to work harder than you thought, and putting out full pops causing them to overheat and thermally cut off after a while.

If manual, were all three 430's set to the same power, or were the ones that died first outputting more power than the other one?

I was using ETTL (or auto) mode. I don't know of overheat could explain it all. It might be, but not so clearly. Also, when I changed the batteries to see if it would be OK, I didn't feel that the Speedlite were very hot. Instead, the 580EX II was pretty warm but it's fine. But it may be because it's dead for a while already and it's therefore cooled down.

Oh, nobody has experienced something similar? No explanation?

sounds like over heat protection to me

What ISO/aperture setting you were using? All depends on what power setting the flash is used at and how fast it is being used.

adamau5 wrote in post #12424681
sounds like over heat protection to me

Me too - overheat protection has those exact symptoms, and completely explains what the OP is seeing.

Are there any other explanations that also completely explain that behaviour?

Intermittent faults are difficult as the flash goes back to working normally again after some cool off time... (note cool off time is determined by internal circuits, so even though the flash bulb feels cold, the flash may still be in cool off mode...)

adamau5 wrote in post #12424681
sounds like over heat protection to me

yup. if the 430EXII i used a lot quickly it gets hot and heat protection turns on and it simply wont work.

wait 15-20 minutes for it to cool off, then it will work just fine.

Thanks for the replies!

It is possible that it's overheat. (And I would be glad if it was, because it didn't cause permanent damage to the Speedlites.) But it's a bit hard to explain why the other 430EX II and 580EX II didn't get overheat as well. In particular, in case of the malfunction of the second 430EX II, there was another 430EX II doing almost the same job but it was working OK. It's a long room. The two 430EX II were located at both ends. Then the middle area was illuminated by a 580EX II.

Yet, again, since I used Auto mode, it's hard to determine whether each Speedlite had the same workload.

bobbyz wrote in post #12425703
What ISO/aperture setting you were using? All depends on what power setting the flash is used at and how fast it is being used.

I understood that I needed some ambient light, which came from big windows, and I needed to avoid overheat. So, I used four Speedlites instead of relying on one or two. Also, the ISO was 800-1600 and the aperture was 2.8-3.5. It's a wedding. All the Speedlites were triggered very frequently, say, 10 times per minute.

colormaniac wrote in post #12426835
I understood that I needed some ambient light, which came from big windows, and I needed to avoid overheat. So, I used four Speedlites instead of relying on one or two. Also, the ISO was 800-1600 and the aperture was 2.8-3.5. It's a wedding. All the Speedlites were triggered very frequently, say, 10 times per minute.

Something else then. 10 times per min at ISO800-1600 and f2,8/3.5 is very low power from flashes.