my machine has been down for 2 plus years now. its been sent to whites at least 6 times and still doesn't work, I gave up on them. they replace everything,new pc board ( 2 times) 3 different coils and it will only pick up a coin if you put it within 1 inch of the coil. well yesterday I took it backout and started playing with it and took the circuit board out, there are 3 variable resistors, 1 on the back side is for volume, but 2 on the otherside not sure what they do butI think 1 is offset and other is delay, just need to know which 1 is what . they are the blue adjustable device. ....1 is near the edge the othermore near the center...... moving these I have increased my coin signal to 11 inch so far. thanks for any help