I'm truly sorry you had a problem with the 580, I wrote the customer. It would work with the Black Box but not with regular batteries. I did see this once before almost two years ago. Investigation showed no pattern to this, isolated case. 

However the 580 at times, has had far more usage problems both with H.V. powered powered packs and some types of AA batteries.  NO panic, we have only seen two cases in three years. 

Just like Nikon had with the original predecessors of the 800 flashes, namely the lower board problems of the SB-28 and SB-80. The SB-800 suffered from a Nikon BF ***. The user combined five batteries and a HV pack. Fortunately NO photographers were burnt in this process but I know two carpets that have battery shaped burns in them when Kodak and Panasonic (same vendor) came out with OXY-DIGITAL AA Cells. 

Never the less I went back and researched the 580. Some early original 580's exhibited several weak links which resulted in the creation of the EX II series which isn't as frail. Rarely do manufacturers admit anything, and Canon and Nikon both have denial modes. Canon had severe focus problems and  Nikon is no angel either with the D2H cover-up. Both finally tackled their problems. Patience my friends.

The usual culprits; Overheating was the usual number one cause as is with all brands; followed by weak springs in the battery compartment; weak green boards and poor heat insulation; poor seals, wet weather was a killer; seals were one of the selling points.  Canon mentioned seals being improved on the EXII. Seals keep water out and heat though so it's a mixed blessing.

The number one killer of all is HEAT.  And against all scientific thinking and common sense...heat is accumulative.   Now since we do not put any heat in the strobe (NO AA CELLS) we generally are not a cause of heat. Repetitive shooting can be.

The first 580's blew in numbers because an anonymous battery company made cables which were over-volted and then adding insult to injury, the guys loaded real fast NIMH for the circuits. So you had heat from the batteries, heat from the capacitors and fast firing mode, AKA The Perfect Storm.

Some never got past the first day. With the NO-NAME pack they still require you to use the battery compartment with AA cells plus their 325 volt by-pass cable to the AC port. That combo simply overloaded the already frail factory pushed 580, it blew them up. Lots of them. See Galbraith Archives. The dispute is whether it was the cable with internal capacitor or overrun on the box. Both parties disagree whose fault it is. 

The Black Box does NOT put any more current into the older 580 than four AA cells. Four AA's are 6.4 or so volts, so it's not voltage. The Black Box is 6.4 voltage at maximum right after a charge.  You have to treat them more gently than the 580EXII. If you do they are a fine strobe. But they have this quirk that sometimes they will run on the black box but not on AA cells. I suspect... 

The only possible answers are as follows and we caution you.
As units get older a weak component in the head fail-safes which prohibits lower voltage. My suspicions are that there is a low threshold resistor which fails because an incomplete charge to the capacitor on the older 580's (shoot before the full charge hit ).
Or the module was inserted BACKWARDS. Because none of us can see into the strobe, when Canon and others work on them we will never know what goes wrong. Thus they went with the 580EXII which is not an upgrade but a totally different model internally.  Less than two years after it's introduction.  Just good marketing to keep the same name  

Quantum announces a Locking Plate for the MB5 cable when used with a Canon 580.  It's small, ingenious and it works. Best part is Quantum will send you one free. Obviously they felt the MB5 door was not as secure just using Velcro, as it should be, and they corrected it. Later kits of the MB5 come with the  a locking adapter plate for the 580 model.  It does not need the door to be closed, it is held in place with a small piece of Velcro furnished with the kit.

Again, if you have purchased a Module MB5 that did not include a locking plate for the Canon 580EX flash, use the order form on their website.  Above is the picture posted on the Quantum website. This is shown as a public service announcement.

Basically it works like this. Place the module in the 580. Press down, slide clip in place, use the supplied Velcro to secure door, voila! Simple doesn't hurt the flash with over power and allows you to use batteries for backup if needed. 

* It locks the cable in place with nothing permanent and no sharp points like on the Vivitar module. In addition no stress is put on the AC port which accelerated units use and damage is easily traceable there should you get a runaway capacitor or surge blow-out.

* Again, It allows the Canon to safely run cooler. The 580 stuffs a lot of electronics into a small package and they are not exempt from over zealous use and overheating.  very common on Canon.

The 580 EXII:  CORRECT CABLE IS MB2
It uses the MB2 which is a locking module from the past brought back for the  battery layout of the EXII.  It is identical in spirit to the locking module of the Vivitar and fits quite a few models however it can be installed wrong, very wrong.  please take a careful look at the photo shown and it was provided for me by Bruce Ward, to whom I thank profusely.  

NOTE:  FOLLOW THIS CLOSELY

The shoe of the strobe is on the left side of the picture and the head to  the right. IGNORE the Canon Markings!

Place the tiny red dot in the position shown which is the bottom of the 580 EX II and facing back to the screen.
You can see a little "+" molded in the Canon Module.
This is the correct orientation.
Use the Velcro supplied to hold the door from moving. around.   
Like I said this module can be installed three out of four times wrong. 

OPEN DOOR POLICY:
For those who have a problem with doors open.  I accept the fact there are those who refrain from jaywalking, won't step on a crack in the pavement and never walk under ladders. They probably spend half their life cleaning lenses, and constantly charging their batteries. From my sordid life as a street shooter and wedding photographer, I see things as tools to be used in the best possible way. I don't mind the door open. 

If it gives me better performance, less electronics better heat dissipation, and components that are stressed and ultimately can fail. And that's my opinion. I get paid for pictures not door framing. I cannot believe those who make an issue of this except it's their quirk. They can't stand the door open. OK, go get a TURBO, still screw with four NiMH and have half the flashes. Plus, the possibility of an overheated unit.

Or suffer with the door slightly ajar which can only help to dissipate heat. HEAT is the number one killer of strobes caused by too rapid shooting exacerbated by over clocking with transformers or external capacitors.  If you have to shoot in the pouring rain, get a Nikonos. I live on a golf course and watch some of these morons with lightning strikes all around them high five-ing that incredible two foot uphill putt. Tampa Bay is the lightning capitol of the world, we named a team after that. Every year we lose more to lightning than alligators.

In addition, other problems with strobes are cranial-rectal dyslexia occurs causing some users to plug something into something they shouldn't, or simply bad luck drops in, and the unit falls off a table. 

RAIN DANCE
So the guy says to the psychiatrist "every time I take my flash out in the rain it gets wet".  The shrink says " Only shoot on sunny days".  Flashes are not waterproof neither are battery packs especially those with large amounts of electronics.  If you have one of those accelerated units costing 500 dollars getting drenched with all that electronics in it, be cautious that's 330 volts of prime time. If you are shooting in a down pour, whether the door is open or closed won't mean a thing, you should have it wrapped in a zip lock, saran wrap or if the rain is that bad get your butt inside because that where everyone else will be. The larger Zip Locks can hold a flash and camera and cut a hole for the lens shade and clear filter, secure with a rubber band.

CANON 420 - 430 EX Users  

There are differences in the configuration so please know which unit you have. Sometimes we have had to alter the configuration requiring nothing more than a Phillip's screwdriver. It has to do with the screw head being long enough to reach the contact and the correct placement.  Must of been a long day at the plant. Or a mis-marked box.  Let me figure it out.  The cable generally is correct when the (+) is in the lower left.  WARNING: If you don't know send me the cable and flash, that's better then sending it to Canon for a repair. That's it for CANON.

BF*** = Brain-Fart