[Maarten]

Thanks!

I think the reliability difference between Dutch and British is more a lockfit characteristic as lockfits seem to fail less over here (as well as in Australia apparently) while TO1 and TO7 cased transistors such as the AF11x types seem to fail just as often in the UK as in The Netherlands.

The tin dendrite problem is quite wide spread, so finding some that are still working justifies taking a note of it to see if there's a pattern. If those types were ever made using a better tin alloy, this would not have been during the bulk of the European production anyway, since they fail so often and consistently.

On a side note, this may have come up before, but does anyone know whether the Matsushita equivalents used to form dendrites as well?

Unfortunately, it's not always clear where a transistor was made, even if it says so in print on the thing itself. Also, I don't know how to read pre-1971 batch codes but hope to find out one day (if anyone knows, let me know!). I will make note of this one in any case, to build up the data to extract this from.