31-12-2016, 11:15 AM
(31-12-2016, 09:42 AM)Murphyv310 Wrote: ... a lot of older crystals that have been lying unused for many years may not work, I've no idea why this phenomenon occurs, some of the ones I have are the big chunky ones that come apart, they have springs to hold the contact onto the crystal and look 100% perfect but wont respond on any circuit valve or semiconductor ...
I remember those! Massive things!
I recall a conversation with a man who had visited a shop in Lisle Street at the tail end of the post war government surplus boom where he found large quantities of these crystals - all individually tested, it was claimed.
He selected the ones he wanted and took them to the counter - it was at this point that the 'individual testing' took place.
Each crystal was plugged into an oscillator to check for activity - most of his selection proving to be very inactive!
No problem, said the vendor, and he proceeded to hurl them onto the floor with considerable force! He calmly picked them up again and plugged them into his tester - every single one now worked!
So, it might work for you, Trevor - you never know!
