Canon 580EX II Problems/Life span

[inlina]

Hi All,

I have 2 580EX II's which are different ages and have been run on different duty cycles. My older one doesn't seem to have anywhere near the output of the new one.

My original one is about 18 months old and I would entimate it has seen around 30,000+ pops.

My newer one is about 6 months old and seen around 5000+ pops.

I used them both for the first time on my pocket wizards about 4 weeks ago and was getting significant shadows casting from one side when I was running them on ETTL and bouncing off umbrellas. I though maybe I didn't have things set-up right and thought nothing of it.

I then used them to do some portraits at an indoor event a few weeks (bounced off umbrellas) ago and found that I had to run the new one at about 1/4 when the older one was 1/1 and I had to position the newer one further away to get the light even close to balance and minimise the shadows.

Last weekend I used my newer on to shoot BMX and found that I could run it at 1/4 and my typical exposure setting for aperture/ISO/shutter whereas the older one I would almost always have to run 1/1.

So, do these speedlites have a typical life span? Can they be serviced (like replacing the tube) to get them back to an as new performance?

I have overheated the old one many time in the past, so I am also wondering if I have fried something or reduced the life?

I will try and take some sample comparison images when I am on vacation next week and bored in the hotel room if that will help.

Thanks,
CG