Hacker Sovereign II , model rp25

[Mark Hennessy]

BC148s are pretty unreliable, and I wouldn't bother obtaining NOS replacements - just use BC108 instead, as that's what the earlier sets used. Alternatively, there are countless modern replacements in a plastic TO92 case if you're not bothered by originality - the BC548 being the obvious one.

Beware - a lot of the AC128s available on eBay and other places use a smaller encapsulation, so there might a need to "alter" the heat sink.