600EXii-RT Stopped Flashing

[Dakota59]

I have a 600EXii-RT problem that I can't figure out. I changed the batteries and now the unit powers on normally, but won't flash, even with the test button. I had been using it for a few hours prior to the battery change and it worked perfectly. No settings on the unit or my camera (5DM4) were changed during the battery swap. I did try replacing the batteries again (they are new and fresh) but to no avail. There are no error messages active on the flash or camera, and the ready light stays red. The flash unit is a few years old, but has less that 500 flashes on it, very seldom used. Any ideas would be greatly appreciated.

[deebatman316]

Hi Dakota59 does the pilot light turn on when the speedlite is turned on. What kind of batteries are you using rechargeable or Alkaline batteries. I also own the 600EX II-RT and found the flash doesn't like rechargeable batteries due to the lower voltage. Rechargeable AA batteries only put out 1.1 or 1.2 volts while Alkaline batteries put out 1.6 volts.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Dakota59]

Thanks for responding deebatman316. I am using alkaline batteries, all new and fresh. And if by pilot light you mean the flash ready light, yes, it is on. It doesn't go green at start up though like it used to, just stays solid red. All other functions work and the display looks like it should be flashing. I am very confused. 

[deebatman316]

Are you able to test the speedlite on a different camera body. Do other functions of speedlite work ie the AF Assist Beam.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Dakota59]

I don't have another camera body to work wit. What's concerning is I should at least be able to fire a test flash off camera and it won't even do that. 

Ron

[deebatman316]

Will the speedlite fire the modeling flash if the depth of field preview is pressed.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Dakota59]

It won't flash when I press the DOF button either, and it is enabled. 

[deebatman316]

Do you have another speedlite to test on that camera.

-Demetrius

40D, 5D IV, EF 16-35mm F/2.8L III, EF 24-70mm F/2.8L II, EF 28-135mm F/3.5-5.6 IS USM, EF 50 F/1.8 STM

430EX III-RT & 600EX II-RT

[Waddizzle]

What camera body are you using?

Does the flash function properly when it is not on the camera body?

[Dakota59]

I have a 5D Mark IV.