help: Aptus ii 12 and Rolleiflex Hy6 mod 2 fail to sync

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Camera: Rollei HY6 mod 2
Back: Aptus12

both are working fine separately (and together functionally, but don't sync with each other).
the camera says "no back" and shoots blanks. the back says ready to shoot but doesn't capture images.
The back is on camera setting: Leaf AFI

anyone has had similar issues? the pair worked on the last shoot

best

[parkn123]

I also use HY6mod2 and Aptus II 10R , these problem appearred when I travel , these problem is due to the Hy6mod2's gold teeth contact problem( not related to the back) . I resumed after improvement made by my "Rollei doctor" . This is the design fault of the Hy6mod2, My "rollei doctor" improved a dozen of Hy6 .

The following diagram showed what improvement made

https://www.flickr.com/photos/54877744@N03/albums/72157701523715641

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I have the same problem.
I've got Aptus 5, Aptus 7 ⅱ and Credo 60 but they don't sync with Hy6 mod2.

How do you improve it and can you teach me who can do it?