Record Player Repair

I have an old Aiwa automatic record player that remains very dear to me because I rescued it from a skip. It is broken now, however. The arm moves horizontally, but does not lower itself onto records. I eimagine this should be easy to fix. Does anyone know where this can be done, in London? I expect to be able to walk into a dusty shop, have the problem solved in about five minutes, and pay no more than £20. Is it possible, do you think?