# ST-E3 Overheating?



## unfocused (Aug 5, 2013)

I know there have been some related threads on this in the past, but the answers seem inconclusive.

I was shooting a series of portraits on Saturday using the ST-E3 RT and 3-4 600 EX-RTs. Near the end of the first session, I started having problems with the strobes not firing. I'd shoot once, strobes would fire. Shoot again, nothing. It was all of them. So, I thought maybe the ST-E3 batteries were dying. Replaced them. Didn't make any difference. 

Fortunately, we were near the end of that series, so went outside to shoot the subjects in some natural light. Came back after 20-30 minutes, turned on the ST-E3 and the 600 EXs and everything back to normal. For the rest of the day, I would shoot for 1/2 hr to 45 minutes inside, then go out and shoot natural light and come back in. No problems for the rest of the day.

Is it possible for the ST-E3 to overheat? 

Since none of the 600s were firing, I doubt if they were the problem. I use battery packs with the 600s as well and all batteries were at full charge at the start of the day. 

I used to have this problem all the time with the optical trigger (ST-E2, on-camera flash controller and the Yongnuo ST-E2 clone) I didn't think it would be a problem with the ST-E3 since it's a radio transmitter and not optical but, maybe it does because of pre-flashes? Anybody have a similar experience or an idea?


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## Jim Saunders (Aug 5, 2013)

I don't have any first-hand experience with the ST-E3 but your signs there are what I'd expect for a device overheating. If there isn't a useful fix out there then I'd send it back for replacement.

Jim


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## Mt Spokane Photography (Aug 5, 2013)

I'd certainly send it in for repair, it should not be hanging up. It doesn't use a whole lot of power, so I would be expecting a defective component.


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## FunPhotons (Aug 6, 2013)

Unlikely since it's just a RF transmitter. The misfiring seems more likely to be local RF interference would be my guess. Doing a spectrum/channel check might have been useful.


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## Mt Spokane Photography (Aug 7, 2013)

FunPhotons said:


> Unlikely since it's just a RF transmitter. The misfiring seems more likely to be local RF interference would be my guess. Doing a spectrum/channel check might have been useful.


 
Good point!


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## Tara Copp (Sep 28, 2013)

I'm late to this conversation, but I think it's your 600s that are overheating, not the St-E3, you'll see in my previous posts I was having some ST-E3 issues. I sold it and bought another 600!as the on camera master instead. I have had fewer firing issues - before I sometimes got no response, as you did. Now, i notice that if I use my flash too rapidly in succession, or have it recycling with an external pack, its not too long into a wedding reception before they overheat, and refuse to fire, or take much longer to recycle and be ready for the next shot. i have also already had to send one back to Canon for repair after the flash bulb burst. I am getting better at being more conservative with my flash use, but it can be frustrating. I carry many extra, fully charged eneloops with me and refresh my batteries before each new portion of a wedding/reception ... I.e. the recessional, the dances, etc - to reduce missed shots. It helps but it is not a perfect solution.


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## David Hull (Sep 28, 2013)

People should keep in mind that this equipment operates in the 2405 MHz-2475 MHz microwave band, the same place where a lot of other stuff operates including, all sorts of wireless devices as well as the worst offender for RFI which is the old trusty microwave oven. 

This thread got my curiosity up and I put one of my 600EX-RT's in the kitchen about ten feet from my microwave oven, and fired my ST-E3 in the living room (about 15 FT from the flash). The result is that it works fine with the microwave off but cannot communicate when the microwave is on -- link lite went out and everything. I have noticed in the past that when my wife runs the microwave my Apple TV and Laptop also loose wireless communication so upon seeing this thread, I thought I'd try the Canon flashes -- yep, sure enough the pesky microwave fouls them up as well.

Perusing the ST-E3 manual, it looks like the Canon system is using the same sort of signaling as IEEE 802.11 b/g (Direct Sequence Spread Spectrum, Offset QPSK) in the 2.4 GHz wireless band. 

Like some of the others here, I would put my money on RFI rather than the ST-E3 overheating (I have used mine a lot and never seen an overheat issue). I think my kitchen microwave is worse than some others, one of my work buddies when hearing my story was surprised since he said he never had issues running his laptop near his.

People with Canon Radio systems should run some experiments. I gaffer taped my iPhone 5 to the same 600EX-RT and didn't have an issue. It seems to fire nicely when located right next to my router as well. So maybe it needs something real strong like a microwave oven to wipe it out. It may be worth some testing for those who are interested in such things.


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## privatebydesign (Sep 28, 2013)

If you are having interference issues then change the radio channel manually (Menu3-CH). Auto works very well until you have an intermittent interfering transmission.

I burn through batteries in the ST-E3-RT faster than the 600-EX-RT, but once I change them no other issues.


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## Lawliet (Oct 10, 2013)

FunPhotons said:


> Unlikely since it's just a RF transmitter.


The only RF transceiver with a back channel to date. The flashes report their state to the controller, telling you whether a hidden flash is ready. If one overheats it at least wouldn't allow the "ready"-light to come back on, probably locking all strobes.


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