Seeing as there aren't any good guides online for the Canon 5D Mk III disassembly, I decided to make one that would allow me to get to the main PCB. I have fixed about a dozen of these in the past two years.

The 5D Mk III has been around since 2012, is a workhorse DSLR in the Canon lineup of cameras, and yet, no detailed guide exists. Hopefully, this one will help you to navigate well enough to delve into the rest of the camera parts as well.

  1. First things first, remove all the rubber hand grips from around the camera to have access to all external screws. Don't worry, these can be put back without any loss of stickiness.
    • First things first, remove all the rubber hand grips from around the camera to have access to all external screws. Don't worry, these can be put back without any loss of stickiness.

    • Remove the plastic around the viewfinder by squeezing the sides and lifting towards the top of the camera.

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  2. Once that's removed, you will see 4 screws that need to be removed.
    • Once that's removed, you will see 4 screws that need to be removed.

    • The top screws are a different size from the bottom screws, so keep the top separate from the bottom.

    • Before you proceed, be sure to label exactly where each screw you remove should go. You'll notice the plastic container near the top of the picture. There are 5 more like it with tape labels stating where the screws go. There are a lot of different sizes holding this camera together and meticulous planning is necessary. This is very important!

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    • Next, remove the silver screw.

    • Then the two black screws.

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    • Turn the camera so the bottom is now on top and take out the three screws holding on the bottom of the back plate.

      • One of the screws is just outside my picture. It's indicated here by an arrow.

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    • This screw needs to be removed next. This is what holds the left side of the entire back plate to the camera and if not removed will cause a major bend in the internal bracket.

    • Remove this silver screw next but keep it separate from the previous one.

    • This screw holds in the battery. Must be removed before the next one.

    • Last screw holding in this side plate. Removing this entire side plate will allow the main pcb to be removed easier later on. You can leave the side plate intact for now and come back to these screws later if you'd like.

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    • You can now lift straight up on the back plate and separate it from the body. Be careful to raise it gently because on the left side it is still connected with a ribbon cable to the main pcb.

    • There is also a metal bracket that drives straight down into the body on the upper left. Be careful to lift straight up on the back plate until this is completely outside of the main body, then flip the whole back plate over to the left so you can reach the ribbon cable connector underneath.

    • This is a snap on connector that can be gently pried up with a small flat head screw driver or a thumbnail.

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    • Remove these four screws from the bottom plate.

    • Remove this screw from underneath the battery door.

    • Remove this screw from the bottom front right. If you haven't removed the rubber grip material yet, now's the time to just take it off.

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    • Remove this screw.

    • Finish by removing this silver screw.

      • You can remove the battery door at any time if you feel it's in your way. It's not necessary, but it may help. There's a small raised black ridge that can be slid to one side to remove the battery door.

    • It's a tight fit, but wiggle the plate gently and pull straight up and out from the camera body to remove the bottom plate.

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    • The reason we remove the bottom plate is so we can access this adhesive black covering. It starts underneath the camera and wraps all the around to the top. We won't be removing the top of the camera for this procedure.

    • Gently pry this adhesive covering up until it is off of the main board at the back of the camera and drape it over the top of the camera. I always try to do this step without cutting or ripping the covering.

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    • From this point on, be very careful. We will be removing or dislodging internal connectors that may be damaged if not careful and will impact the camera functions if not seated correctly when put back together.

    • First, label the two ribbon connectors with top and bottom and be sure which side attaches to the main board and which side attaches to the secondary board on the right. This is important because these connectors only go on one way and can not be switched.

    • Next, remove each connector like you did earlier with your nail or a small flat screwdriver.

    • Using that same small flat screwdriver, you will need to remove these two connectors from underneath the main pcb. Pry gently from each end of the connectors until they come loose.

    • Using some tweezers or a very small set of needle nose pliers, gently remove these two connectors from the top left of the main pcb. Be careful not to pull on the wires, ONLY the white connector ends to pull them out.

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    • These connectors have very small hinged flaps that must be lifted to let loose of the thin ribbon cables they're holding.

      • The flaps can be damaged very easily if not careful! Very gently use a dental pick or your nail to pry them upwards to release the tension on the cables underneath.

    • These ribbon cables may be gently pulled from the connectors with a small set of needle nose pliers. The one at the top of the board has a hole in the cable, so something very small like a tooth pick can fit in here to help pull the cable free.

    • This connector must be pried up with extreme caution. You absolutely can not pull on the wires leading into the connector as they are extremely delicate and will break easily. Using a small flat head screwdriver, pry up on either end very gently until the connector pops loose.

    • Underneath that connector is another that will need pried up. This one is another ribbon cable similar to the ones we've previously lifted with a small flat screwdriver.

    • Remove these three screws. They are all the same size.

    • Finally, remove this screw. It's a different size from the other three, so keep it separate.

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    • If you hadn't removed the side media port plate earlier, now is the time. This allows full access to the side of the board.

    • Now you can remove the main pcb from the camera body and replace if necessary.

    • To put back together, do all of these steps in reverse order.

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To reassemble your device, follow these instructions in reverse order.

9 other people completed this guide.

Attached Documents

Matthew Zeller

Member since: 09/23/2015

640 Reputation

2 Guides authored


Hello, how do I purchase the main board...? Do you have a dealer I can buy from? Thanks alot

Cineview Motion Pictures - Reply

Hi mate I'm in Australia and I got mine from the USA on Ebay for $350AUD delivered

Nathan Tanner -

Thank you so much for this guide. Very helpful. I had an issue with my 5d m3 not powering up, was told by a repairer in a qoute that they tested the main PCB and it was faulty. I swapped the PCB for a new one myself which made no difference - camera was still a brick.

Investigating on the web I found that when this issue occured most people would report that the DC/DC PCB was replaced, so I swapped this PCB and the camera works perfectly.

To anyone having this 'no power' issue I would recommend changing the DC/DC PCB FIRST and then the main PCB if unsuccessful.

The costs for me were:

Main PCB $350 - Ebay

DC/DC PCB $80 - Ebay

Shipping to service center and quote $50

Quote for main PCB replacement $815 (I rejected the repairs and it myself)

I am confident that the main PCB was ok, but I'm not changing it back to find out!

Good luck and be careful with the scews! The heads strip very easily, use the proper screw driver, keep pressure on them and dont over tighten!

Nathan Tanner - Reply

Thank you for this guide mate, it is very helpful. Also I have a request, Can you post how to remove Canon 5D Mark III's top cover? My 5D dropped and the top cover cracked also its LCD is broken. I have ordered a new replacement 5D top cover and I am looking to repair it by myself. Looking forward to get your help.

dean.jems - Reply

There is an attached file with the parts in exploded diagram view. I believe it's page 3 that will show you the screws necessary to remove. I have only needed to remove the top cover once before and it wasn't difficult. Keep in mind that the ribbon cables on the right may be attached to the top. I can't honestly remember. As with most cameras, remove the top cover slowly and keep a sharp eye for anything still connected.

Matthew Zeller -

So refreshing to know that there are good and knowledgeable people out there willing to share info with the rest of the world . Thanks guys and stay blessed .

Yaw Asamoah - Reply

Hey Nathan! My 5DM3 just went belly up today. No power, at all. I was happy to find your comment about the DC/DC PCB. Where is this part located in the camera. I'm guessing it's on the opposite side of the main PCB? Thanks so much for sharing your knowledge on this.

Best ~ MJ

Michael J. Walls - Reply

Doh! Scratch that Nathan. Just saw the parts PDF. (Sorry. It's been a long day of maintaining my composure when your "A" camera turns into a door stop.) Still, thanks of the directions to eBay and what to look for! Best ~ MJ

Michael J. Walls - Reply


Can you please guide me on how to remove the top three ribbons on the main board.. i was able to successfullyremove the bottom ones but top ones especially the 2nd and 3rd ribbon cable from right are not coming off..those are the ones you marked with red arrows..pls help

sunilgubbala gubbala - Reply

Sunil, the far right just pulls out. Use a toothpick in the hole and pull towards the top of the camera. Use your thumbnail or a plastic spudger for the middle one. You have to lift the black part. It’s on a tiny hinge, so be careful. The far left one can be done the same way but you have to lift the white part, NOT THE BLACK PART.

Matthew Zeller - Reply


When you have replaced the main board, have you done any adjustments and if yes, what kind of adjustments needs to be done?

Also, as I understand it, the main board has also the firmware installed, what version of the firmware have you had?

best regars, Hannes F.

Hannes - Reply

Hi Hannes,

Did you get any answer to your question? I will replace the main PCB and I want to know if I have to perform other tasks after the replacement.



mathieu geffroy -

Hi, thank you so much for the guide! I would like to know if there are many other steps to reach the shutter unit, i need to change it and i don't know if i could do it on my own only with the attached pdf file!

Matteo Borgers - Reply

Matteo, I haven’t had to remove the shutter before, so I’ll have to dig into one and get back with you. If nothing else, take a close look at the PDF attached to this guide with the parts blown up.

Matthew Zeller -

Hi!I got this damaged:

Is there any replacement part for that?Thanks in advance

Franzkekko - Reply

Hi Franzkekko, sorry for the late reply. If you broke the little black plastic toggle, then no. You will need to replace the entire part. Without that toggle, the camera will not power on. It’s a safety feature to make sure the card reader door is closed.

Matthew Zeller -

Thanks a lot for this tutorial.

I will try to change DC/DC board…

Damien BG - Reply

I have change the DC/DC (no problem, it’s not so hard).

But now, when I turn on my camera, top LCD doesn’t work and I can’t acces to the main menu and take photo…

Are you sure that no reprogramation is need after changing the DC/DC?

Thanks a lot (sorry for my english, I’m french)

Damien BG -

I reply to myself but it could be interessant for someone. I decided to dismount again my body after previous dysfonctions. I discovered that the right connector that we can see on the step 10 of this guide wasn’t well connect…

My 5d works Now peefectly after changing dc/dc board

Thank you again for this guide wich help me to dismount somme parts.

Damien BG -

Great tutorial, I want to change the top cover for a 5D Mark IV - will you one day have a tut for this?

Ginger Photographer - Reply

Possibly. I wouldn’t mind working on a mkIV. The trouble is, I don’t have one to work on, yet. Thanks for the support!

Matthew Zeller -

I opened up my camera to replace the top cover and now when I put it all back together the camera won’t turn on. I check all the cables and they are all connected. Any ideas of what it could be? I really don’t know how to diagnose the issue

Paul Ferradas - Reply

Check the card slot door. Near the top is a very small black plastic lever. If this is broken or bent back into the camera, the camera will not turn on. Everything on the camera is designed so that if a single cable, connector, etc. is not in place, the camera won’t even power on. This includes the battery door and card slot door.

Matthew Zeller -

Hi all,

I will replace the main PCB and I want to know if I have to perform other tasks after the replacement. (such as initialization or anything else?)



mathieu geffroy - Reply

No, but you must be careful on the revision of the replacement board. It must match the board you’re replacing or your camera has a very good chance of not working right or at all. That happened to one of the cameras I tried to fix and now I just use it for spare parts. Good luck!

Matthew Zeller -

Hi Matthew,

Thanks for your help. I changed the main PCB and my lens problem is solved (err 01, lens not recognize). Now I can take picture in live mode, in Manual Focus with the viewfinder but if I want to use the AF and Viewfiender the sutter button dos not work at all. No focusing and can’t take picture. I tried to reset all parameters and upgrade the firmware to the latest version with no effects.

If anyone has an idea.


mathieu geffroy -

I’d go through the menu first and make sure the shutter button is set up properly. Make sure the shutter activation hasn’t been set to another button on the camera or disabled. I’m not sure if that’s possible with the mk iii, but it should be a quick and easy check. Double check the revision of your replacement board. Where did you get it from? It’s possible it’s incompatible with your specific camera. Recheck all the connections, something may be amiss. Are any other errors showing up on the top lcd panel or the rear screen?

Matthew Zeller - Reply

Hi Matthew,

I’ve started to reset all the menu and personnal functions before write here.

I finally recheck all the connections and found one which was not push enough. Now everything is OK.

Thanks a lot for your help and tutorial.


mathieu geffroy -

That’s great, Mathieu! I’m glad you were able to find and fix the problem. Enjoy your repaired camera!

Matthew Zeller - Reply

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