The needle is not touching the Agar?

The needle holder touching the plate rim before the needle usually causes collisions. To fix this, loosen the needle screw and lift the needle slightly before retightening for an immediate fix. For a permanent solution, pour thicker plates and recenter the needle. Contact technical support for more help.

Answer: 

This usually occurs when part of the tool holder touches the rim of the plate before the needle does. Have a look underneath the plate as you raise the needle and you will see where it touches.

More information can be found here : Why is the needle holder colliding with the plate before the needle touches the agar?

Remedy:

1. Immediate remedy : Remove the plate, slacken the screw holding the needle (while holding the needle with tweezers), and lift it so that the bottom of the needle is just clamped when the screw is re tightened. This raises the needle 2 - 3 mm. Not a lot but often enough to work with.
2. Permanent remedy: Pour slightly thicker plates You will need to recentre the needle afterward but you should be able to dissect with the needle lifted slightly.

If you require more information please contact [e-mail] for assistance.