help needed with coil/hall sender

hi folks,
         is there anyway of testing the coil on a 83gti, also can hall senders in the dizzy be replaced or is it a complete unit? any idea were i can get them?

cheers is advance

You can test the coils primary and secondary resistance, Haynes gives you the procedure.
The hall sender can be replaced as a unit - I noticed that Big Boys Toys are selling them the other day