28-06-2017, 12:24 PM
Interesting page Mark. Regarding the lockfit noise problem, I have had similar problems including total failure of TO106 encapsulated silicon transistors used in 1960's Tektronix gear. I put it down to problems with early epoxy encapsulation, which over time creeps sufficiently to put strain on the device and bonds between the device and legs. Similar to the epoxy potting of HT transformers. Tek used to wax pot them, which worked perfectly. Then they went to epoxy for just a few years (in the late 60's/ear;y 70's), until they found it went lossy over a period of time and the 30kHz oscillator no longer oscillated. Then they went to silicone potting in about '73, which again works perfectly.
Craig
Craig
