AWVFS fretsaw trouble

Hi

I have a AWVFS which has seen me good occasional service over several years.
I’m experiencing a few problems with it and would love some advice from more experienced tool users.

Today the whole upper blade holder assembly has been working loose and has jumped out a couple of times. When I screw it back in (the arm itself has thread inside, it goes in with a tooth washer only as far as i can see from the manual), it turns but doesn’t bite tight - and so works itself loose quickly again.

Any ideas on how it can get it back into use?

Try using slightly longer screw or using thread lock to hold it in place