580ex manual mode inop

I tried to search but could not find this exact problem. Its probably user error which would be better.

580ex2 flash on 20d. manual mode on camera. ettl mode works perfectly on flash, but when I switch to manual mode on the flash and fire, no flash at all.

I have checked everything I know to check on the camera and flash, but I do not understand why it will not fire in man. mode but will work perfect with all other modes.

help please.

Does the flash fire in manual mode if you press the Test button?

I can't think of any setting that can turn off the flash in manual mode yet fire in ETTL mode.

No fire from the test button either.

When you set the flash to manual mode, do you get the "M" icon showing on the LCD screen? I'm trying to determine if maybe it's the Mode selection function that's broken and not actually putting the flash into Manual mode.

yes. The "M" is showing. I read the flash manual about 5 times to try and figure it out. The section for "manual flash shotting" is very short and too the point which pretty much tells me it should be the same to operate.

well ok...while writing this post, I grabbed my camera real quick to try it again. It just worked perfectly. Now I am confused. I guess it might have been just a freak problem. Sort of how error codes come on the screen of 20d's for no reason and work perfectly a few minutes later.