7D Flash Issue - Err 50

Hi Everyone,

I'm new to the forum, hoping to leverage your expertise in helping me find a solution to a problem I'm having a Canon 7D. I recently replaced the shutter on this camera and being a newbie to camera repair, I did not discharge the flash capacitor before doing so. At one point during the repair, I accidentally touched the discharge point on the flash circuit board (CY3-1754-000) with my tweezers, which caused a spark. After assembling the whole camera, it wouldn't turn on and the battery icon would flash on the top screen.

I replaced the flash circuit board with a new one (including new capacitor which had to be soldered on). After this, all functions worked properly, but the flash would not engage. It would pop up, but wouldn't fire, and the camera would shoot off an Error 50 (Electric Control Malfunction). I replaced the flash assembly itself, but am still getting the same error.

Things I've done to troubleshoot since then:

- Reseat all the cables that I disassembled during repairs

- Measured capacitance on flash capacitor (270uF) as well as on the smaller one next to it (310 uF)

- Measured resistance between yellow connector pin and flash capactor (-), as well as red connector pin and flash capactior (+), both of which were around 0-2 Ohms, so there is a connection there.

- Measured voltage in flash capacitor right after trying to fire flash. Measured 0.5V

- Checked resistance between various IC pins and compared with previous damaged board. All values are more or less the same

Not really sure how to proceed further. Don't want to throw money into another new flash circuit board, especially if the issue isn't with it. Any help would be greatly appreciated. Thanks!

Welcome!

Well, without true circuit schematics it is difficult to troubleshoot things like this.
I would definitely say the short you created damaged another component in that circuit or downstream from it or....or it damaged a connection (wire/ribbon/trace/ect​)
Given it would not power on at all I would have thought you damaged the DC-DC board, the power distribution board for the whole camera..
But it eventually turned on...and worked fine except the flash...
Remove the ribbons that connect the flash board to other parts of the camera. Remove the cable/wires that connect to the flash board.
Look over everything, board and cables/ribbons, very carefully on the flash board and any/all connections to it if you have an inspection scope and/or some way of magnified inspection. I am willing to bet you may have blown a connection on a ribbon cable or wire harness. Check for burns and open connections in the cables/ribbons and the connectors on the board(s).
I have seen the small copper pads on the ribbons cables get blown open from shorts and cause an open in that connection...
If you do not find anything there start looking at where those cables/ribbons connect to in the rest of the camera (probably just the main board but not 100% sure without one in front of me).
Great thing is you can buy most of these parts on ebay. If you cant find it Canon MIGHT still have some in stock, but the age of that model is not in your favor.
If you find a burn, great. If not, I have to say, you might be better off selling it for parts/repair and buying a replacement 7D...just my 2 cents though.
But it might also be a fun project for you if you enjoy this kind of stuff..In that case, Good luck!

Found the root cause! The flash circuit board that was sent to me was faulty and was missing an oscillator. Without an oscillator, the flash won't fire. Going to open a case with the seller and get a replacement. Thanks for all your help!

Good work! swapping out a shutter is not for the faint-hearted, did you take photo's of the dismantle/assemble?

Wow. Who would have thought there would be a missing component on a brand new part..? QC is a thing of the past apparently.. LOL!
Glad you found it. Good luck with the next one

Yep. Here's a photo of it after disassembly and swapping out the shutter. Challenging, but definitely much easier than swapping out shutter blades, which requires a lot of care with the tiny springs inside.

You are a lot braver than I am!