meter now fully working! I removed the IC,I had previously soldered in. Carefully checking tracks and vias,I found the via from pin 1 was open circuit,and repaired it with a single strand wire put through the hole,and soldered to the offending track either side of the open circuit. This got the meter working,but readings were dancing around the correct reading.By grounding 4 inputs on the unused inputs(not originally done when manufactured),and recalibration,meter fully worked!