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G6Tanuki · 19th Oct 2019, 5:25 pm

I don't think there were any long-term 'good' AF114/5/6/7/8 transistors - the tin-whisker-growth does seemingly proceed at a variable rate (I can remember replacing AF117/OC170 transistors in the receive crystal-oscillator/multipliers and 10.7MHz IF-strips of Pye Cambridges/Vanguards back in the early-80s - we didn't really know about the whisker-issue then but replacing the transistors got you up and running again).

Pragmatically, I'd say your radio's only still working because of chance!

I recently was given a Bush TR130 [designed by Tom Karen - otherwise famous for styling the Raleigh Chopper bike and the Reliant Scimitar] which didn't work; on investigation the screen-leads had previously been snipped but the IF-amp AF117 had since gone dead. The owner wanted 'originality' so I bought and fitted a NOS AF117 - with the caveat that I viewed this as a sub-optimal solution and it was not guaranteed to last.

19th Oct 2019, 5:25 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,996	Re: Good batches of AF11x ? I don't think there were any long-term 'good' AF114/5/6/7/8 transistors - the tin-whisker-growth does seemingly proceed at a variable rate (I can remember replacing AF117/OC170 transistors in the receive crystal-oscillator/multipliers and 10.7MHz IF-strips of Pye Cambridges/Vanguards back in the early-80s - we didn't really know about the whisker-issue then but replacing the transistors got you up and running again). Pragmatically, I'd say your radio's only still working because of chance! I recently was given a Bush TR130 [designed by Tom Karen - otherwise famous for styling the Raleigh Chopper bike and the Reliant Scimitar] which didn't work; on investigation the screen-leads had previously been snipped but the IF-amp AF117 had since gone dead. The owner wanted 'originality' so I bought and fitted a NOS AF117 - with the caveat that I viewed this as a sub-optimal solution and it was not guaranteed to last.