In the case of my Milano and the 91 164S, the radios worked, so not a fuse problem, but the plastic toothed drive straps inside the tubes broke and left the antennas up.
So, if the radio works, the problem is usually a broken part in the antenna itself, generally the plastic drive strap. Also, the antenna power wire just plugs into the back of the radio (which controls the movement of the antenna), so check that connection.
In the case of my cars, the rebuild kits didn't work, so I just bought new powered antennas from eBay, about $20-25. They have worked fine for years. A little fiddling with the actual mounting may be required, as usually these are universal units, but usually it is no problem, either inside the fender, and the through the fender grommet.
If the radio doesn't work, check the radio fuse (see the owner's manual), and the wiring on the back of the new radio to make sure everything is hooked up and properly connected. Check that the adapter wiring hookup harness, if used, is the proper one for the car and new radio combination.
1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27
previously owned since 1964:
62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6
Last edited by Del; 07-10-2018 at 10:36 PM.