[Arran]

Mike;
  Is there any chance that the speaker in the 39-6 may just have a break in the field coil or does it look burned? If the cone and frame looks like they are in good shape it may be worth trying to salvage it if possible. I don't know about the speakers used in the 39-6 and 39-7 but in some speakers the pole piece can be pressed out and the field coil bobbin removed for rewinding, on some you can even unbolt the pole piece and bracket but I don't think that they did this with small Philco speakers.
Regards
Arran