Recently at a wedding, I was sitting down for dinner and had placed my camera on the chair next to me. The 580ex was attached to it along with the CP-E3. Of course, the CP-E3 was attached to me, so when I got up, the camera and flash took a short tumble. Took a quick look at it and found the hot shoe mount have cracked. Had a 430ex with me, so I just threw that on and worried about it later.
Got home and the next day, found the 580ex wouldn't fire. After some searching, I figured the flash tube has cracked during the fall. I came across this article on fixing the 550ex:
There were also cross section diagrams for the 550ex in PDFs, but none for the 580ex. The 580ex shouldn't be too different. So I called Canon US parts and had them look up the part for me. Apparently, they don't sell the flash tube separately anymore. Only with the reflector assembly and wiring. I checked with two reps to be sure. Here is the part number:
CY2-4135-000 - Holder Assembly, Main Lamp
Thankfully, the cost was only 30.78 + shipping. The 550ex tube was quoted on the above link for $12, so it wasn't too much. And also I don't have to do any soldering whatsoever. Anyways, here is the new unit.
Disassembly of the head is quite easy. Lift the rubber stickers and it will reveal 4 screws on each side. Remove those. There are also 2 more screws on the flash head. Take those off.
Now you will be slide one half of the housing off. The other half is attached with two screws that you will need to remove. Here is what it looks like with both sides off. There are still wires attached to one side for the wide panel diffuser sensor. I just left it on.
The lamp assembly is held on only by screw (1). Once remove, that black piece will come off as well. There is a spring and holder under (2), so make sure you don't lose that. The spring is used to push the holder down which has a nub on the end that goes into the rails that zooms the head. Also I found it necessary to remove screws (3) so that the lamp assembly could be released.
Take note of how the wires are placed in (1). There is an extra wire, that you find in (2). It is for some sensor, and you will need to detach that and place it on the new one.
Here is a close up. As you can see, (1) goes inside (2). But inside (2), there is also part (3) and (4). Not sure what they are, but (3) is on the bottom, then (4) goes on top, then (1) is inserted into (2).
You will need to loosen the PCB from the white housing by removing the two screws below. You need to do this to route the connector that you see in the first picture to the outside. Also, there are tape that holds the PCB down, so you will need to lift those to get it loose.
Now reattach everything and you should be set. I replaced my shoe mount as well and that was a piece of cake. In case you want the part number, it is: CY2-1227-000 @ $3.50 each.
Here you can see my old lamp assembly. Clearly, the middle has cracked along with some micro cracks around it. As you can see, the white rubber part is ripped. White taking it apart, I found the rubber there has melted to the flash tube. Making it impossible to remove without damaging that part. So, if you are able to just get the flash tube separately, you will need to get that rubber part as well. On the right is the broken shoe which I fixed with some super glue. It is actually quite stable after fixing, but it is only $3.50 for the part to replace, so why not.
Disclaimer: Just a word of warning. The capacitors in the flash can hold its charge for a LONG time. And you can get a HUGE shock from it. You should google how to discharge them. I left the flash empty for 2 weeks, and I still got 2 tiny discharge which I felt.
Canon US Part Order number: (732) 521-7230
Everything is in perfect working order now. Very happy with it, and took about an hour to fix. Well worth the savings since Canon wants 100+ to fix.