If you have built and tested the circuit with MPSA65, then you can blame BC516 otherwise there may be some other problem.

Did you notice that pinout of alternate transistor may be different than origianl?

This is not a very critical transistor, any good PNP with low VCE(sat) can be used. I personally use 2SA1015 for switching power to different portions of a circuit. 2N3906 should also work.

Regards

IA