Author Topic: Is there any electronic guru on these platform? Need help wit a canon 70D PCB  (Read 1957 times)

Cadyllac

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Hi guys, I have problems with a canon 70D PCB that initial was dead and now I made it to make it work partially but I don't know how to take any future actions. Since as you know, it is quite impossible to do these kind of repairs without schematics unless you're quite good at it, witch is not my case :P
So now the camera powers up and the top lcd works with all the info, some buttons near top lcd are working as well but no main menu and no taking pictures. I found that the SOT-23-5 (5 pin power converter transistor?) was fried, unfortunately there's only a letter and a number on it so I don't know what exactly the characteristics are. It says H4 and is mounted near the f74966a chip. I manage to find a similar one but with a H3 on it on a canon 5D II motherboard. I don't know if the partial working problem comes from this or there is something else to do.
Any thoughts?

Thanks in advance!








a1ex

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What was the original issue (how did it die?)

Did this camera have ML installed before?

If yes -> prepare a bootable card and try the portable ROM dumper, and also the current ML build. If you get any sort of activity (LED blinks, crash logs), I can take it from there.

Otherwise -> any activity from the UART pins in the battery slot? One of them should output debug messages from the MPU (the f74966a chip, apparently fully working, as it handles the top LCD) and the other should output debug messages from the main CPU.

Last resort: JTAG.



I've asked Daniel Rozsnyo (he found the 600D UART pins) to look at these pictures.

Quote
10:44 <danieel> by the look, it is not a regulator - which should have input and output capacitors, and at least 2 thick wires for in/out above
                the large ground
10:45 <danieel> so this one is a single logic gate, TI calls those "little logic", the package is not SOT-23-5, rather it is SC-70-5
10:46 <danieel> the H3 is a dual-input NOR gate: https://www.onsemi.com/pub/Collateral/MC74HC1G02-D.PDF
10:46 <danieel> the H4 is a dual-input OR gate: https://www.onsemi.com/pub/Collateral/MC74HC1G32-D.PDF

Cadyllac

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What was the original issue (how did it die?)

Did this camera have ML installed before?

If yes -> prepare a bootable card and try the portable ROM dumper, and also the current ML build. If you get any sort of activity (LED blinks, crash logs), I can take it from there.

Otherwise -> any activity from the UART pins in the battery slot? One of them should output debug messages from the MPU (the f74966a chip, apparently fully working, as it handles the top LCD) and the other should output debug messages from the main CPU.

Last resort: JTAG.



I've asked Daniel Rozsnyo (he found the 600D UART pins) to look at these pictures.



Thank you a1ex for all this information!
Regarding the story of the camera I don't know, I'll try to get some information from the prevues owner. The two chips are looking very similar, I will follow your suggestions and see if something comes out.

Thanks again.

Mike Tornado

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So you have MPU (camera subsystem) is worked, but ICU (digital subsystem is dead). I think there are generic issue for EOS 70D.

EOS 70D have a serious issue with digic cooling, especially in video recording mode.

This issue is accepted by Canon and they started free main pcb exchange programm.

Check yours camera serial number if it's 00xxxxxxxxxx - 22xxxxxxxxxxxx you have affected camera.
Go to autorized service center for free replacement (no active warranty is required, this a Canon problem not yours).

More info: https://www.usa.canon.com/internet/portal/us/home/support/product-advisories/detail/service%20notice%20eos%2070d%20error%2070%20or%20error%2080/

If you for some reasons can't to to canon service, there is a some ways to extract calibrations from dead board and write it to a new board, which you may buy in some place like ali or ebay, but, you must buy only new revision with new cooling.
There is no knowledge that is not power

Cadyllac

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So you have MPU (camera subsystem) is worked, but ICU (digital subsystem is dead). I think there are generic issue for EOS 70D.

EOS 70D have a serious issue with digic cooling, especially in video recording mode.

This issue is accepted by Canon and they started free main pcb exchange programm.

Check yours camera serial number if it's 00xxxxxxxxxx - 22xxxxxxxxxxxx you have affected camera.
Go to autorized service center for free replacement (no active warranty is required, this a Canon problem not yours).

More info: https://www.usa.canon.com/internet/portal/us/home/support/product-advisories/detail/service%20notice%20eos%2070d%20error%2070%20or%20error%2080/

If you for some reasons can't to to canon service, there is a some ways to extract calibrations from dead board and write it to a new board, which you may buy in some place like ali or ebay, but, you must buy only new revision with new cooling.

Ha! Nice one Mike, starts with 17 :D. Ive heard about this issue but I didn't check enough.
I was wondering did canon will accept it since was opened already?

Thanks!

Walter Schulz

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Only one way to find out ...