Author Topic: Problem with rear scrollwheel on 5D Mark III  (Read 1007 times)

70MM13

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Problem with rear scrollwheel on 5D Mark III
« on: March 01, 2019, 01:01:18 PM »
Offtopic: my 5D3 was defective, so I was more or less forced to take it apart. It's now working again, but I have no idea what I did to fix it (other than disassembling and reassembling it a few times, and trying to run some diagnostic routines).

Just out of curiosity, what were the symptoms?

a1ex

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #1 on: March 01, 2019, 01:56:14 PM »
It's been in this state for a couple of months; no idea what the issue is.

1. First cold boot (after battery out): usually everything fine. Sometimes starting directly into state 2 or 3, with low probability.
2. Second (warm) boot: almost everything working, except rear dial.
3. Third (warm) boot: DryOS fully booting, GUI on the screen, but camera locked up. No reaction to buttons or card/battery door. Of course, the defect was also present without card, after clearing all Canon settings etc.

Before writing the above message, I've disassembled it a few times, reassembled, but there were no signs of getting better. I could, however, isolate the defect to the rear dial PCB (the one with a black ring on it). If I started the camera without that PCB, it worked fine (no lockups). If I started the camera without the back cover, but just with that PCB attached, the defect was present. There were no signs of damage of that PCB. On that PCB there is a small IC, 7147 ACPZ, talking to the rest of the camera (guess: to the MPU) via SPI. Image annotated by Danieel.



At some point I've started to probe the UART to look for interesting messages. Usually, I turn the camera off from the card cover, as it's faster than from the power switch. With the debug wire attached, I found it easier to use the main switch. After a few reboots I've noticed it no longer locks up. It was working again - that's when I wrote the previous message to document the UART pins.

Reassembled everything, but after putting back the last screws... the problem occured again. Oops! I still had the debug connector accessible, so I've tried to power-cycle it and see if there's anything interesting on the UART pins. While the camera was locked up, I've noticed the MPU restarting itself (printing MON>>> and E1OFF in a loop). Normally, the first message is printed at startup and the last one at shutdown.

Pressed the power switch / mode dial assembly a bit harder, I think, and it's back to life. Will see for how long.

Also found some factory routine that appears to check or calibrate the rear scrollwheel. They didn't seem to help or hurt, except at some point I've got scrollwheel events without any user input (as if the sensitivity was too high). They were gone at next reboot.




Not yet sure whether it was the scrollwheel PCB, or the power switch, or something else. I'm not yet able to get diagnostic logs from the MPU.



Edit: after typing this, the defect is back. One update: from the "completely locked up" state, I can turn off the camera by applying some force on the power switch. Just actuating it normally keeps the camera powered on and locked up, i.e. no reaction at all.

Edit: alive again. Go figure...

70MM13

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #2 on: March 01, 2019, 03:36:50 PM »
the intermittent nature of it, and the pressure application to power cycle it suggests a possible cold solder issue?

just a dumb guess from someone who had to deal with that for decades in studios...

to a hammer everything looks like a nail :P

keep us updated on this, it's very interesting!

Mike Tornado

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #3 on: March 08, 2019, 05:30:39 PM »
It's been in this state for a couple of months; no idea what the issue is.

1. First cold boot (after battery out): usually everything fine. Sometimes starting directly into state 2 or 3, with low probability.
2. Second (warm) boot: almost everything working, except rear dial.
3. Third (warm) boot: DryOS fully booting, GUI on the screen, but camera locked up. No reaction to buttons or card/battery door. Of course, the defect was also present without card, after clearing all Canon settings etc.

Before writing the above message, I've disassembled it a few times, reassembled, but there were no signs of getting better. I could, however, isolate the defect to the rear dial PCB (the one with a black ring on it). If I started the camera without that PCB, it worked fine (no lockups). If I started the camera without the back cover, but just with that PCB attached, the defect was present. There were no signs of damage of that PCB. On that PCB there is a small IC, 7147 ACPZ, talking to the rest of the camera (guess: to the MPU) via SPI. Image annotated by Danieel.



At some point I've started to probe the UART to look for interesting messages. Usually, I turn the camera off from the card cover, as it's faster than from the power switch. With the debug wire attached, I found it easier to use the main switch. After a few reboots I've noticed it no longer locks up. It was working again - that's when I wrote the previous message to document the UART pins.

Reassembled everything, but after putting back the last screws... the problem occured again. Oops! I still had the debug connector accessible, so I've tried to power-cycle it and see if there's anything interesting on the UART pins. While the camera was locked up, I've noticed the MPU restarting itself (printing MON>>> and E1OFF in a loop). Normally, the first message is printed at startup and the last one at shutdown.

Pressed the power switch / mode dial assembly a bit harder, I think, and it's back to life. Will see for how long.

Also found some factory routine that appears to check or calibrate the rear scrollwheel. They didn't seem to help or hurt, except at some point I've got scrollwheel events without any user input (as if the sensitivity was too high). They were gone at next reboot.




Not yet sure whether it was the scrollwheel PCB, or the power switch, or something else. I'm not yet able to get diagnostic logs from the MPU.



Edit: after typing this, the defect is back. One update: from the "completely locked up" state, I can turn off the camera by applying some force on the power switch. Just actuating it normally keeps the camera powered on and locked up, i.e. no reaction at all.

Edit: alive again. Go figure...

I fix a few cameras with this issue by firmware update, did you try this?

A factory routine that you've found is used to adjust this dial in service centers.
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a1ex

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #4 on: March 08, 2019, 06:40:27 PM »
I fix a few cameras with this issue by firmware update, did you try this?

Thanks, but... didn't seem to help. Tried reflashing 1.1.3 in both "good" and "semi-locked" state, a few times.

Oddly enough, when reflashing in the "semi-locked" state, the rear scrollwheel works for selecting the confirmation for the firmware update, and also right after the update, without having to take the battery out. It stops again at next reboot.

edit: right, a software reboot triggered from ML appears to clear the issue in a repeatable way, even from the completely locked up state. The issue is back at next reboot performed from either power button or card/battery covers.

Mike Tornado

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #5 on: March 08, 2019, 07:09:36 PM »
OK what about Factory Reset ?
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Mike Tornado

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #6 on: March 08, 2019, 07:16:05 PM »
also looks like powerline problems. Try to temporary unsolder two capacitors near fpc connector on dial board.
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a1ex

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #7 on: March 12, 2019, 04:12:00 PM »
Factory reset: done, did not help. Cleared all Canon settings, but didn't help either.

Factory routine (calibration or whatever it is): after running it a few times I've ended up with sensitivity set too high (scrollwheel events without me touching it). The setting was not persistent (the high sensitivity disappeared at next reboot).

Power problems: possible, as the power button seems to have something to do with the lockup. I can no longer reliably power off the camera by forcing that button, but I used to be able to do that.

UART activity in the "locked up" state: the MPU appears to restart (i.e. to print its usual messages again)
- every time I press some button
- every 2 seconds, if the power switch is off and the camera is still on

Auto Power Off appears to work in the "locked up state", too. If I leave the camera untouched for about 1 minute, it powers off. Mashing buttons for about 1 minute => still powers off. It doesn't seem to be watchdog resetting the MPU, as the main CPU clearly receives a shutdown message.

For now, I've got a software workaround - after a warm boot, perform a software reboot. This appears to clear the error or whatever it is. So far, so good, except for a few seconds required for the reboot. Interesting thing - after a software reboot (via PROP_REBOOT), PROP_STARTUP_CONDITION reports the same value as after a cold boot. It reports something different after a warm boot. Go figure.

I'll open it up again at some point, but it's no longer a priority. Camera usable again, to some extent, but still defective.

70MM13

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #8 on: March 13, 2019, 04:43:36 AM »
That's great, you finding a software workaround...  I hope it keeps working for you!
Is it affected by temperature?

a1ex

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #9 on: March 13, 2019, 08:05:59 AM »
Maybe. When it seemed fixed, it was usually after some time of tinkering. After leaving the camera in a "known good" state for some hours, the defect was back again.

IDA_ML

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #10 on: March 13, 2019, 01:23:29 PM »
Did you try cleaning all mechanical/friction parts with isopropyl alcohol?  It could also be a spring that has gotten loose and does not press contacting pads hard enough.

a1ex

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Re: Problem with rear scrollwheel on 5D Mark III
« Reply #11 on: March 13, 2019, 01:59:44 PM »
The scrollwheel operation does not rely on mechanical contacts. See the 7147 datasheet linked above.

I did clean other buttons that had minor problems; they are working fine now, but they were not related to this defect.