Yes it looks like I have issues elsewhere, hence my checking of ferrite wires and switching etc. I have had far too many radios with these exact tuning issues ie quiet stations touching ferrite coils improves etc that have ended up going to the grave
. I can never seem to solve these types of tuning problems and trawling through the forum it seems I am not the only one, lots of abandoned threads that contain no problem solved.
As my question has been answered and the bc557b works in a fashion as a replacement for the af117 in the osc position on a stella st415t, the thread can be closed. Thanks to those that suggested the replacements
.
Regards Poppydog