Konica SD511 Folding Unit keeps jaming when folding/stapling

[refillman]

Machine Konica Minolta C224 with SD511 Finisher
no error message
Fault: every time i try for a folded /stapled booklet the unit jams up

so first whilst I was printing some booklets off my fold knife snapped, so ive had to get it welded,
I've put everything back and done the motor test in SM and everything works,

tried to print a folded single sheet and it work no problem, so I tried to print a booklet 12 pages and it jams, tried an 8 page booklet and it jammed
I've noticed that the leading edge stopper is all the way up which I think is correct but the Trailing edge stopper bar is in the closed position so the second sheet hit into it causing the jam, have I somehow got the unit out of sync.

Many thanks

D

[copier tech]

Machine Konica Minolta C224 with SD511 Finisher
no error message
Fault: every time i try for a folded /stapled booklet the unit jams up

so first whilst I was printing some booklets off my fold knife snapped, so ive had to get it welded,
I've put everything back and done the motor test in SM and everything works,

tried to print a folded single sheet and it work no problem, so I tried to print a booklet 12 pages and it jams, tried an 8 page booklet and it jammed
I've noticed that the leading edge stopper is all the way up which I think is correct but the Trailing edge stopper bar is in the closed position so the second sheet hit into it causing the jam, have I somehow got the unit out of sync.

Many thanks

D

This is a precision part so welding it to factory standards is impossible.

[refillman]

the fold knife holder part is unavailable i couldnt find this part anywhere, if you can point me to a place i can get one from it would be very much appreciated.