[Ted Kendall]

The failure mechanism on the Rifas is, I think, triggered by damp, and mere inactivity in long-term domestic storage can be enough to set it off. The seal between casing and leads fails, mositure gets in, partial failure causes cracks in the casing as the paper swells, this lets more moisture in, degrading the dielectric further, until the thing erupts. I wouldn't give more weight to duff Rifas than the condition of the tape path when estimating hours, for this reason.