Quote Originally Posted by aasmaukr View Post
Okay, no problem Do you have a digital multimeter so you can measure the resistance between ground and pin 8 of the chip?
OK!

multiply the resistance between ground and pin 8 by 20.
I.E. if the resistance is 2kohm you need a 40kohm VR (or 50kohm will do too, but preferably not any lower than 40kohm).
Where's 20?