[DIY] – Canon 580EXii repair

Broken flash tubes are one of the most common ways a flashgun comes to an early demise. Unfortunately, the cost of professional repairs often make repairing a strobe a unfavorable proposition – at $150-200 minimum labor charge, often just for diagnostics alone, repairing a flash would costs about the same as buying a new one.  In this installment of the TwinGeeksPhoto.com blog, I’ll show you how I repaired my 580EXii flash gun so that Rachel can take two eTTL capable flashguns on her trip to the UK.

Before we proceed further, do understand that a standard hot-shoe powered flash gun contains high voltage components.  A 300mA jolt across a human heart is enough to induce fibrillation and cause the heart to stop, and the photo flash capacitor in a flash gun has more than enough juice to do this under the right conditions.  In other words:  THIS CAN KILL YOU. Perform these repairs at your own risk; we are not responsible if you kill yourself.

Years ago, when I was in primary school in Hong Kong, my Dad gave me an Olympus Stylus range finder to learn photography on.  It had an external clip on flash, powered off a single AA cell.  One day, after watching the Batman movie, I decided I wanted to build a bat signal, and a good way to do so would be to use the flash.  I correctly hypothesised  that the two recessed metal contacts on the side of the flash were used to trigger the flash, and also correctly deduced that shorting those two pins would cause the unit to fire.  When I proceeded to short them out, with 2 sewing needles pilfered from my Mom’s sewing kit, the flash fired – and sent me across the room.  I had made a potentially fatal mistake of holding one needle in each hand, and as such the electricity went through my chest.  The resultant chest compression was so severe that it (combined with the impact of hitting a hard wood floor) knocked the breath out of me.  Had that been a Metz potato masher, I might not be around today.

That little story out of the way:  let’s get started.

Parts needed:

Flash head:  The 580EXii’s flash head subassembly is integrated with the zoom motor and the high voltage ignition coils.  This makes repairs more expensive, but on the bright side, there is no high voltage soldering involved. The part # from Canon is CY2-4227,  and at the time of writing, US$63.23 from Canon Parts Service.  You can contact Canon Parts Service directly at: +1.732.521.7230.

Silicone oil:  The 580EXii is weather sealed.  This is accomplished by a special molded O-ring like gasket.  Over time, and after disassembly, this gasket material loses its sealing efficiency.  To get around that, I wet my fingers with medical-grade silicone oil and lightly oil the gasket on reassembly.

Medical grade silicone oil is often sold and marketed as “Water proof sex lubricant“.  And, yes, that’s really what I purchased it for – my bottle is quite a few years old and very much unused…


Any well stocked DIY maker type should have the following tools:

*  Jewelers’ screwdriver set.  I highly recommend Wiha tools – they are German made out of Vanadium tool steel.  The set from my college days still works beautifully.  Local in Seattle, Hardwicks & Sons carries them.

* Optional:  A “spudger” – often an engineering plastic pry bar, for prying apart the plastic casing.  I actually don’t own one;  it’s next on my list (I’ve been making do with dental picks…).  You can buy them from iPhone / iPod repair stores, such as www.ifixit.com

Let’s get started:

There.  Now, take the jeweler’s screwdriver, and remove the screws shown.  For the screws hiding under the cosmetic santoprene trim plates, carefully remove the trim by inserting a screwdriver or spludger down along the edge of the trim piece, then gently prying it up.  The die-cut adhesive tape will lift out with the trim piece.

Next, with a flathead screwdriver, gently press down on the plastic spring clip on the swivel button side of the flash gun.  This unclips the two halves of the upper flash head enclosure.

Don't use excessive force!

Observe that there are 4 wire bundles coming into the flash head subassembly.  A larger ribbon cable carries the command signals as well as power to the zooming flash head, while a smaller, but much thicker gauge cable carries the actual lines for firing the flash.  THESE LINES ARE CONNECTED TO HIGH VOLTAGE AND CARE SHOULD BE TAKEN WHILE HANDLING THE UNIT.  At this stage, the voltage is probably ONLY 300V or so; it is enough to give you a very nasty shock.  Off the coils, however, the voltage can be in the kilovolt range, which will paralyse muscles.

HV and control cable bundling disconnected for clarity. Note the flex circuit ribbon entering the flexible printed circuitboard assembly for the flash head subassembly, about 9o'clock position to the copper coil. Do not damage the connector / ribbon cable!

Standard procedure, for anyone who’s ever worked with high voltage, is to discharge though a 1 megaohm resistor.  Most people don’t have a 1 megaohm resistor, so you can *carefully* short the contacts with a screwdriver with an insulating handle.  Sparks could fly when you do this, so be warned.  (In my case, I havn’t had batteries in this flash for over a year, so no fireworks.  Still, I shorted the pins just to be sure.

High Voltage cabling assembly.  Dont touch the solder ends without discharging the capacitors first.

Molex (tm) connectors for the high voltage cabling assembly. Don't touch the solder ends without discharging the capacitors first ... it hurts.

Next, disconnect the molex connectors.  A spludger works; I used a flat jeweler’s screwdriver to carefully pry them off.

The two other wires that are attaching the flash head are the following:  A small ribbon / flex circuit to the flash head’s flex PCA, and what appears to be a grounding, conductive plastic wire of some sort to the polycarbonate housing.  Remove these.  Remove any excess glue on the black grounding wire.  You will tape this back in place with scotch tape.  Pay attention not to pull too hard on the flex, those suckers are delicate.

Now, remove the 2 black screws holding the white polycarbonate housing.  The fresnel lenses will probably come out too.  Note the orientation and order of the fresnel lenses; the gasketed lens is in front with the ridges facing out.

This frees the flash head subassembly.  Replacement is in reverse order, for the most part.  Don’t touch the flash tube, or the output glass – oil on fingers tend to shorten lifespan of these components.  I found it easiest to tape in the black grounding wire, then the power and signal cable bundles, then install the subassembly into the housing with the two screws.  Finally, carefully hook the hole in the flex circuit connection with the end of a toothpick and slide the connection into the mating connector.

After the connectors are in, reinstall the fresnel lenses.  I use a little bit of waterproof sex lube silicone oil to lubricate the O-Rings, so that they maintain their weather sealing.

Reassemble in reverse order and test.  Voila!