Ehwaz,

My best guess is that your BD243C is 'goosed' as we say here in the UK. I have had one of the p.46/ Fig. 33 oscillators running for a while now. Every time it has failed it has been the transistor. Stick a diode tester on it.

In my experience the circuit as shown is quite finely balanced and excursions, even small ones, from the values shown can have a big effect.

In due course you might like to try a MJL21194 based version. Use it with a 100ft 18AWG trifilar coil based on a Pittsfield sized spool with a welding rod core. You need to reduce the value of the three resistors around the transistor by a factor of 10 and leave all other component values as they are.

Note the base load resistor needs to be about 3W rated.

This device really kicks bottoms (polite phrase). Be careful if using a quadrifilar coil as I have, the unused strand has quite a kick to it!!

Regards

Richard