how to repair BT 3500 Studio phone base (Master) unit?

about BT Studio 3500 cordless phone.
The wire from the black 3-pin "device" to the phone broke due to me carelessly tripping over it. I stripped the insulation from the internal blue & red copper wire covering layer. I thougt this was carrying "mains" (240V) so I connected the copper to the Line & Neutral pins of a spare 3-pin mains plug. I plugged it into the mains, switched on, and heard a low volume "blip". Nothing worked!!
Looking at the old plug carefully there is some small writing which says it is basically a 240V A.C. to low voltage (9V ?) transformer & rectifier to D.C.
I unscrewed the bottom of the base and tried to lift off the base, but it seems to be glued.
Is there any way of removing the base? I used to be an A level Electronics teacher, so can I solder in new internal fuse, or whatever? Or do I have to throw it away, and buy a new dual BT cordless phone?
Any help/suggestions gratefully received....
Rich