thanks for that guys, thats what i was sort of doing today i was playing around with a 555 timer to try and drive 1 scr today but had no luck i had it conected straight to the scr via a resistor , than i tryed using a cap , i smoked my 20v power supply then fixed it and i tryed a little transformer i made but no luck, there is one prob with this cct as i dont have the spec for the scr they are made by ge i should have written down the number on them but i just wanted to get out of the joint tonight, i think the power supply smoked because of the way the other service tech had hooked up the cro but its still stumping me, the idea you have sounds good but i am not to clued up on scrs and the way the work, they seem a bit confusing i thort i had nutted it out untill today.