Hope them wires come out ok unless your gonna connector block them?

Yeah it's a bit of a gamble getting them out. Sometimes gently pulling the cable whilst twisting will release it, other times the cable just snaps off! I'll see how it goes. I could solder & heat-shrink a new cable on but it's not ideal

Proper work horse ballasts!

These have a release slot. Use a very small terminal driver, push it GENTLY into the slot above the bit of stuck wire and then GENTLY push the screwdriver down towards the table. Wire can be pulled out as you do this. DON'T push driver in too far or press down too far or you'll bend the bit of metal that grips the wire. If that happens, it's actually possible to slide the whole plastic assembly out, remove the metal tabs, re-bend them and then put it back together. In my opinion, one of the best ballasts ever made these. VERY rare to see one fail unless you really abuse it!

Many thanks! I've just been to have a look and yes, the cables come out very easily with that method.

Some of the ballasts have had the cables tugged out so violently that it's pulled the complete plastic thingy off!! The little metal tabs are still firmly attached though so I can solder cables to them or use a standard connector block. No worries

Cool! Like everything, it's easy when you know how A real shame these stopped being made in the early 80's as in my opinion, one of the best ballasts Thorn ever made.

I think they went on til 1991 with this design I have some BETA 2 lanterns from that date with these ballasts sadly one is dead due to water but that's only the real way you can kill one of these

Ah, that's true, I think Kev is correct in stating this design continued in their discharge fittings for a while after they stopped putting them in their fluorescents. They went over to a slimmer design of fluorescent ballast and whilst ok, it wasn't as good as these