EOS 6D Mark II Error 70 when trying to turn on live view or take a picture

[Bowerick]

Hi,
I'm receiving error 70 when trying to turn on live view or take picture on 6D mark II. 
LCD display is working fine. I can access menu. 

Few testing scenarios on video

1. check LCD functionality
2. run live view -> error 70
3. take a picture -> error 70
4. sensor cleaning + clean manually -> mirror do lockup and sensor is exposed but after 2-3 seconds mirror is back and error 70
5. turn on mirror lockup function + take picture -> after first click on shutter button mirror do lockup and shutter is closed after second click on shutter button error 70 

https://www.youtube.com/watch?v=ZBTBY2AHzsU

Any ideas what is causing problems? I tried different lenses/ batteries and removing/ formatting SD-card. I tried remove battery/ SD-car for few hours. I was able to see older pictures on LCD panel.

[Waddizzle]

Not a good sign. Stop cleaning it. 

What lens are you using?  I suspect your camera needs service. 

https://support.usa.canon.com/kb/index?page=content&id=ART177684 

[Bowerick]

Samyang 12mm f/2.8, Sigma 24mm f/1.4 art. The same error for both

[kvbarkley]

Do you have a Canon lens to try?

[Bowerick]

no 

[Bowerick]

I didnt mention that this camera was astro-modified. Original UV/ IR filter was replaced(not by me) with Baader filter that allow more IR light[1]
After modification the camera was working fine but I was not able to focus with my 12mm lens- focus was little bit behind hard stop. After some investigation I found out that it was most probably caused by incorrect sensor position- maybe less than 1mm.

After few weeks I found courage to try to fix it by myself. There are 3 screws on springs which keep sensor in correct position. I tried to adjust them by 1/4 of a turn in clockwise direction but I was not able to move then in any direction... So I reassembled camera but I am now receiving error 70. The most probably I accidentally damaged sensor?/ motherboard?/ ...  with my lumberjack fingers and the only solution is fix/replacement at canon service but first I wanted to try all other possible fixes.

Thanks anyway!

[1] https://noctilove.co.uk/astro-modification-guide/

[Waddizzle]

I’m sorry. Your camera has been modified and you have taken it apart to make repairs. Your issue is beyond my ability to diagnose in a forum. 

[Bowerick · Accepted solution]

Just for info for people with a similar problem. I fixed the camera by disconnecting and reconnecting the flex cable between the motherboard and the sensor. I think I accidentally partially disconnected it earlier.