How to Repair a Canon Flash Hot Shoe

By Conrad Erb, Conrad Erb Photography.

This article contains three parts:

Introduction and Disclaimer

disclaimer: This tutorial was written in 2006, using a Canon 20D, and has probably saved photographers a tens of thousands of dollars on repair fees. Since writing the tutorial, I have heard from people using these techniques on all sorts of other Canon cameras, including the Canon Rebels (all sorts, from the XT to the Xsi), as well as the 30D, 40D and 5D Mark 1 cameras. I bet that it would work on the 5D Mark 2 as well, but unfortunately, I can't promise it will work on your camera.

So, this is for informational purposes only. You undertake any repairs to your equipment at your own risk. Also, don't be an idiot with high voltages. Do NOT open up your Canon flash unless you know exactly what you are doing.The charged capacitor can seriously hurt you. If you mess up your camera, or if you go to the hospital because you messed with your flash, it is YOUR fault, not mine.

I am not a Canon flash engineer. I have no relationship with Canon. I'm just a guy with a few tools and an interest in getting my Canon flash to work.

All clear?

Great! So. I'm Conrad, and I'm a wedding photographer. Flash is really important to doing my work (and I try to use it well, which means bounce flash and off camera flash and almost never direct. If you don't know what those terms mean, do yourself a huge favor and check out the fantastic flash work by David Hobby at or Neil van Niekerk's tutorials).

After thousands of frames on a camera, and you may find that your camera suddenly stops communicating with the flash properly. This can result in 1) the flash not firing at all (very frustrating) OR 2) the flash only firing at full power because the TTL communication is not working (probably not what you want either).

Canon flashes can go wrong for a lot of reasons, and we can't solve all of them (for example, if you drop a flash and it no longer fires, you can only send it back to Canon. If it gets wet, don't mess with it.) A lot of flash problems can't be solved without a visit to the Canon factory repair centers. However, some of the most common problems can be solved with a bit of time and effort.

Before proceeding, check two things (obvious, but you can overlook these):

1) That the flash works properly by itself (you can put on another camera or pushing the 'TEST' button and change the manual power settings from the lowest to the highest).

2) If your camera has a custom setting for the flash, check to make sure that the flash is set to fire! On the Canon 20D, check custom function 07.

At this point, instead of calling your camera manufacturer and making a service request, you may want to investigate whether your flash's hot shoe (the part where the flash sits on top of the camera) has anything to do with the problem.

All of my flash troubles have required minor repairs to the hot shoe, and following is a quick demonstration of what I have learned you can do if your flash is not being recognized by your camera.

How to tighten a Canon flash shoe

It sounds obvious, but the first thing to check is whether the flash is firmly mounted in the flash shoe and the switch is turned on! Making sure that the flash has fresh batteries, insert it completely into the hot shoe and turn it on.

After doing that, check is whether hot shoe is loose. With the flash mounted on the camera, give the camera a gentle shake or put forward pressure on the flash body. Does the flash rock back and forth in the shoe? Can you see a wiggling space between the flash shoe and camera? See below for a normal and a loose flash shoe.

The above is a normal flash shoe with forward pressure being applied to the flash. There is no space between the shoe and the camera body. The ETTL connection pins are barely visible. Compare this with the image below.

A loose flash shoe will mean that the flash rocks forward under gentle pressure, clearly showing the ETTL connection pins. Compare w/ the image above.

If the flash hot shoe is loose, the flash shoe screws should be tightened.

To tighten the screws, you will need a jeweller's screwdriver. They can be picked up at your local hardware store for a few dollars.

A screwdriver.

Put a light colored cloth on your well-lit work surface (to keep from losing small screws), and get a clear view of your flash shoe.

The camera, ready for surgery. Notice the bright lighing.

Use the screwdriver to lift the black hot shoe plate and slide it back. You will notice the hot shoe plate has a curved lip and prongs that 'catch' parts of the hot shoe. If the plate doesn't slide out easily, don't force it. Look carefully at the catches, push them down gently and the plate should slide out (FYI - the plate is what makes it so easy for the flash's pins to slide into the hot shoe quickly. Without the plate, mounting the flash is a real pain.).

Gently lifting the plate.
And pulling it back...

You should see four screws on the corners of the shoe, one large circular flash 'trigger' contact and four small circular flash ETTL communication contacts. Tighten the screws in the corners.

Removing the screws in the corners of the flash shoe...
(in the image above, you will see the bottom right and the top left screws because the other screws are missing because I tighten my flash shoe so much! see below for more information about how to order more screws.)

Consider using Loctite

Note: I have started to tighten these screws every few weeks. If you tighten frequently, you may want to find some Loctite (basically a glue for screws) and apply it on threads of the screw before screwing them back in. Be careful using Loctite - I don't think that it conducts electricity, so use only a little bit and keep it away from the flash contacts. Any Loctite on the flash contacts could interrupt the communication between flash and camera, making it impossible to use automatic ETTL.

This is Loctite. I picked mine up at the local hardware store for a few dollars.

If you lose screws

If you are a complete klutz like me, you may lose a few screws in this process, and you will find that they are hard to replace. Most hardware stores do NOT stock this type of screw. You can try eyeglasses repair kits, but most small screws from these kits are too thin, too long, or don't sit flush with the flash shoe (they make bumps on the shoe and may prevent the flash from sliding onto the shoe entirely). If you need extra screws, call Canon USA Parts at 732-521-7230 and press option 1. Ask for part # CB18049 and verify that this will work in your camera.

I ordered them in late 2006, and they cost 24 cents each and $6 for shipping. Pretty good deal to solve a problem once and for all!

Once the screws are tightened, slide the flash shoe plate back on (no image here - just remember not to force it. it should seat itself easily). Test your flash in manual and ETTL modes.

Did it work?

If your flash works, congratulations, and I would recommend keeping the screwdriver in your camera bag along with a few extra screws in case you lose them next time you try to tighten. I find that the flash shoe can become loose at inconvenient times (most recently, on location at a shoot in the Caribbean!).

If that doesn't solve the problem, continue to...

How to test for a switch problem on a Canon camera's flash hot shoe

If the flash shoe does not wiggle, and the flash is still not working, then the problem may be that the camera does not know when a flash is mounted, and the flash switch is not functioning properly.

Here is how you can find out:

1) Mount your external flash in the hot shoe.

2) Press the button to release the internal flash.

That's right. Mount the external flash and then press the button to pop-up the internal flash. Does the internal flash pop up and hit the external flash, (causing Error 05 on a Canon 20D)? If yes, then the flash switch may be missing and needs to be replaced.

If your camera pops up the internal flash with the external flash mounted and then shows ERROR 05, you are probably in luck! Your flash switch is likely missing and can easily be replaced.

If you have never seen it, this is ERROR 05.

Some background on what is going on: Canon bodies have a small plastic plug hiding under the left prong of the flash shoe plate. The plug presses down when you mount a flash, telling the camera to talk to that flash, disabling the use of the internal flash. If the plastic switch somehow goes missing (either by falling inside the camera or falling out), your external flash will not work b/c the camera won't know when an external flash is mounted.

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How to replace the flash switch on a Canon flash hot shoe

Look very carefully at your flash shoe. If your camera's switch is intact, you should notice the black flash plate has two prongs, one on each side. Look under the left prong for a small plastic plug. I don't have an image of what it SHOULD look like because both of my cameras needed this repair. However, looking at the image below, the white plastic plug should be in the same place where you now see a small piece of metal paperclip peeking up from under the hot shoe plate prong.

See the little grey metal piece under the prong, to the right of the brassy part of the prong? That is where the white plastic plug should be on your Canon 20D.

If you don't see the plug, then replacing it might solve your flash problems. Let's begin!

Find a paper clip. Better yet, find a few of different thicknesses, because you will want the clip to fit without too much play. I am using a standard 'large' paperclip that can be found at most office supply stores in the United States. I would guess it is roughly 1.5 inches long (roughly 4 centimeters long).

A regular office paperclip.

Get something that will let you cut the paperclip cleanly without bending. I am using a pliers-like tool that looks like this

A kind of pliers. I don't know the technical name.

Remove the flash plate as before. Unscrews all four corner screws and put them in a safe place. Gently lift off the flash shoe and put that in a safe place. You will be left looking at the black metal body and the five metal contacts (four small ones for proprietary ETTL communications, one large one that serves as the trigger for generic flashes).

The shoe area is ready for surgery.

Test the paper clip to make sure that fits snugly into the hole on the left side. Tip: try to find the thickest paperclip you can that will still insert smoothly into the hole. If the clip is too narrow, it might not stay put. Once you have the right paperclip, use the pliers to cut a piece 4-5mm long (around 1/4 inch for Americans) . See the illustration for an approximate size comparison to the flash shoe. Keep the paperclip handy, because if you don't get it right the first time, you can clip another piece. (If you cut the piece too short, it just won't work as it should when you have the external flash mounted. If you cut the piece too long, it will push up too high against the shoe plate and make mounting the external flash in the hotshoe a pain.)

Getting the size of the paperclip piece just right.

Gentle put your new switch in the hole on the left side. Do not push it too hard because you might push it all the way in and will never come out. The switch should gently sit in the hole with around 4mm (around 1/8 inch) visible.

The new switch made from a paperclip sitting in the camera.

Put the flash shoe back on and tighten the screws.

Putting the flash shoe back on.

You should notice the new part (which I will call the switch) peeking out approximately 2 mm above the flash shoe. See below.

The switch peeks out.

Slide the black flash plate on. again, the switch should be barely noticeable under the flash plate.

The top of the switch can be seen above the largest flash contact, and to the right of the burnished part of the flash plate.

Did it work?

Mount your external flash and try it out. If it works, congratulations. If it doesn't work, then your switch might not be long enough. Make another switch that is 1mm or 2mm longer and try again.

I repaired both of my Canon 20D flash hot shoe's with the above techniques and have had no problems since. I have also received hundreds of emails from other Canon users telling me that the repair worked on their Canon RebelS (many versions), and lots of other Canon cameras, including the 20D, 30D, 40D, 50D and 5D.

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Questions, comments or if you need more help...?

If you are having any more trouble, feel free to email. This is me when I had longer hair. I don't bite. I'm really busy, so I can't promise being able to help or answer every email personally, but I try to answer at least 50%. Be specific.The more specific your question is, and the more details your provide, the more likely I can help.

This scary-looking guy is the author. Here is his website.

Share the love.

If this information was useful to you, great! If you want to show your appreciation in a monetary way, consider a small donation to support the work of Doctors Without Borders, or donate to help earthquake victims in Japan via Unicef, or help support the international development and aid work of Mennonite Central Committee.

Copyright Conrad Erb 2006, Conrad Erb Photography.

contact me at: flash (AT) conraderb (DOT) com

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Dear Conrad,

For three months I have been going insane due to a 'misfiring' 580ex mkii...until I read your quick guide on how to fit a new trigger pin in the flash shoe.


So this email is by way of thanks for a simple fix that has saved me much frustration!

Kindest wishes,

Craig _________ , West Coast Scotland, UK.

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Conrad Erb Photography • Refreshingly Real Wedding Photography
Philadelphia PA • Traveling Worldwide
888-595-3850 •

© Conrad Erb Photography 2006.