28-02-2015, 10:43 AM
I have now fitted a 70 degree Thermal switch (cut-out) in series with the supply to the mains transformer primary, with the cu-out mounted in the centre of the o/p transsitors' heatsink, and, although I haven't attempted to get the temperature of the H/S up high enough to open the cut-out, the amplfier should now, hopefully, be adequately protected against future failure, at any rate, due to thermal runaway! The Thermal cut-out is secured to the H/S with self-tapping screws, and I applied a smear of Heatsink Compound before screwing it in place.
