"N_Cook" wrote in message
...
Lee wrote in message
...

googling
alternistor "600 volt" site:co.uk
throws up no UK suppliers for 600V alternistors
luckily no one ever uses a snubber in this use, usually just a triac,
so
replaced with an ordinary 600V triac and turns on and off ok,
presumably
maker had a stock of alternistors , so used them instead of a triac
there





Depends whether you count Digikey as a UK supplier (they have UK pricing
and supply to the UK) - they list them anyway.

Digikey seemed to list alternistors but not 600V ones.
The failed one has no T1-gate resistance in the 10s to low hundreds of
ohms,
is that a (sometimes) characteristic of alternistors ? otherwise no gas
venting through the epoxy fill or other signs of distress

Its a long shot - but check out the ST semiconductor range of triacs for
electronic florescent starters, they have to withstand the back emf from the
iron cored ballast, and presumably a pretty sharp dV/dT.