Gareth Magennis wrote:




OK, so I am still of the opinion that nothing could have caused that diode
to fail other than the diode itself (?)




** There are a couple of scenarios* that allow the 4kV rating to be exceeded & if the spiking is at a high audio frequency, the diodes may dissipate enough heat during switch off to cause failure.

Fact is, such diode DO sometimes fail and ought not cause collateral damage.


" Like plugging a jack lead from speaker output back to an input causing massive NF oscillation with no speaker load.



..... Phil