The radio on my 91 FLHTCU started going down hill with individual switches and speakers failing to operate. Now the head unit will not turn off and preset buttons will not operate, dead in the water. Once I pulled the unit out to test continuity of the wires (which resulted in resistance beyond the norm leaning to problem switches as well as head unit) nothing operates except the back light on the screen. Any input on repairs or replacements for this old of a head unit? Any input on upgrades for this old of a bike? I have seen kits for newer bikes to move away from the antiquated tape deck but nothing for a 91. End state I would like to have handlebar controls back for whatever I can put in.