sigma stuck zoom

[hoeke.dijkstra49]

I have a Sigma 70-210 af apo (old type) , ik have a problem with the zoom it is stuck, I have it particularly open but need to open the front barrow to get to the guides because the screws fall out the back end and can see the damage inside.
Can anybody help me out drawing movie or what ever.

 

[bjornl]

This might help:
https/www.youtube.com/watch?v=du-VhKbO0I0