I suppose that the placement is not symmetrical. Check if the lifting is always on the same diodes at the same lead. The general picture for tombstoning shows a perpendicular position, but it is not a must. Check if the lifted termination is solder wetted on the circuit. Melfs are known to be problematic. Gaby Becerra Alejandro wrote: > > > We have had problems with lifted components (Like tombstoning but the > component is lifted just above the solder in one pad) > > The component is a MELF cylindrical diode. > We made solderability test (Dip and look) and we did not found any > differences between the terminals. > We measured the component and we did not found differences between the > diameter of the terminals. > The component length is 3.4 mm and the diameter is 1.5 mm. > I have pictures of the cross section of one defect but I could not > attach them in the mail. > Cross section shows that one terminal is "sink" in the solder causing > a lifting in the other terminal. > A 6 mil. stencil is used in this process. > > > > Alejandro Becerra > > Phone (915) 841-8439, Fax (915) 841-8401 > > [log in to unmask] >