[Sean Williams]

Ah, that's a pity, but not uncommon - previous owners may well have just run the audio stage into an 8 ohm speaker - the 2.5 watt output gives plenty of volume even into a horrendous mismatch, well at least until the optx dies.

Hopefully you will be able to resolve the matter with some spares from a donor set - sadly I no longer keep a spares donor.