Riso MZ790U Machine Won't Accept Drum #2

[unwork_inc]

Drum #1 on this machine works fine, but Drum #2 just won't go all the way in.

Please review the attached image below:

2018-03-23 16.56.20.jpg

You can see that the drum connector and lock mechanism (the rectangular part with the 3-point screwed piece) for #1 (left) is in the correct position. Whereas on #2 (right) it's pushed forwards. This seems to be what's preventing Drum #2 from being inserted all the way into its correct position. I've tried gently pushing this piece back but it seems tightly in place and I wouldn't want to damage it.

Any ideas how to go about this?
Thanks in advance

[unwork_inc]

Re: Riso MZ790U Machine Won't Accept Drum #2

Fixed: There's a white plastic gear at the back of this piece which actuates the horizontal alignment of the piece. If you patiently rotate this gear with your thumb the piece gos back into its normal position.