This 7d has been repaired a few months ago with an ERR20 error code after each shooting. ERR20 could mean many different problems, here is he internal ode:
Interesting is, that, the internal error 215 is Mirror position problem, as possible case you find here the mirror OR the shutter phase switch.
I disassembled the mirror mechanism, the phase switch or brush was OK. I put some grease on the wheels, assembled – ERR20.
OK, let’s see the shutter,. On that unit they were no signs of any damage, but I ordered the ne shutter. Replaced – and ERR20 was over.
I made a few test shots, and gave back the camera to the owner.
After 2 months he called me: ERR20 again…
OK, I read out the error codes: ERR215…
I disassembled the whole thing 3 times. Checked each socket and cable – NOTHING. no corrosion, no damaged wires.
After a new disassembly of the mirror mechanism, I observed, that the motor has –given by construction a relative big play, it is mounted on some rubber bumpers. When pushed in a certain direction, the gears were slightly blocked. Ouuups. I checked a disassembled 40d. That on has no bumpers, the motor is mounted on the plastic chassis.
The small “O”-rings are really very weak. So, I took some other screws, and I mounted the motor without any rubber rings (just the rubber base on motor side). Motor stands now rigid on the plastic base. To be safe, that the motor ill not get loose, I put some 2k glue on one side too (Poxipol)
Mounted it, checked: no error. 50 shoots: no error.
And after this, i remembered, that in the past this happened me once. I checked on my blog …. Yes , it was exactly my own 7d – exactly the same failure, the same repair. (see below)
I think, this is a constructive given problem. Could happen by any other camera having the rubber dampers.
I should read more internet, before working a lot.
Canon 40d motor revival in the body of a 7d
This is a story about my own 7d, which has been flooded with water, before I have purchased it “as it is”, practically not working. I repaired it in a few hours -worked well after.
After a certain time stopped working, message was Exposure not possible, ERR20. Mirror moved up, but the curtain not. Other lots of hours of repair, disassembly-assembly. Normally I should change the shutter, but is really expensive. So i have rather bought the SPT software for the 7d.
I have read out the fault memory. And it was a problem regarding – the mirror motor position.!!!
Disassembled again – no sign of anything unusual.
Assembly – works. Second day in the morning – NOT working.
I resoldered MANY times a damaged cable socket, which was not so easy, as the former corrosion has damaged the contact surfaces.
Then I realized, that touching the motor, the camera works. Pushing it in another direction, the fault appeared immediately. Wow. The motor here is fixed to it’s frame only through 2 flexible points – 2 screws and two rubber collars. I disassembled a 99% similar motor from an old 40d – this has no flex joint, just two screws. No problem – I had no other solution anyway. So, i made both operations (out and in). And even after 3 days the camera is working perfect.
So, never give up!
Canon 7d – ERR20
After exposure, ERR20 – shooting is not possible message. This means some mechanical failure.
Official Canon advice:
Description: A malfunction with the mechanical mechanism has been detected.
Resolution: Turn the power off, then remove and re-install the battery. Then turn the power on again.”
Or say a prayer, whatever.
Reading out with SPT software:
This means, the mirror position sensor is not working. I disassembled the camera, and on the flex cable which comes from the sensor, I have found a tiny oxide dot (or what).
I washed it away with normal water, then I treated it with some methanol, to take away the water.
And now it works, and no error code!