I have seen an abnormal rate of failure of this yig on the 70900A/B and 8562A. Other yigs on the 8560,1,3 ... , the 8350 plug ins, the 8340...are very reliable and I am puzzled by this problem. Did HP/AGILENT look at the causes and get an explanation : size involving overheating, failure of the detector in the ALC ??? Thanks.