Hello,i've buy an used fluke 867b for its components test ability,but this is the only function that doesn't work well,so i try to explain the problem. The display seems to work with little flashing black point,i think that there is a unwanted ac ripple,but the problem is that there isn't the line in the middle of the display;this line is down near the border of the display.When i connect a components like resistor or capacitor this line become a large point always near the border of the display. I've look in service manual but there isn't nothing about this problem. I hope that the problem is avoided with a new calibration,but any suggestion will be appreciate very much.