I agree though with the other poster that it seems strange that your odometer still works but the speedo doesnt.. that would logically state to me that the problem is in the gears within the speedo housing that are broken.
The gear driven part of the speedo is the odo. the speedo is driven by a spinning magnet and the magnetic force turns the needle by electrical flux. The two parts are completely independent of each other in operation.You adjust the speedo reading by adjusting the gap between the magnet and the little horseshoe tabs that the spinning magnet pull around against some spring pressure.
The odo is entirely mechanical and nonadjustable. It is setup by the internal gearing and the gearing in the speedo drive.
The speedo needle failure is possibly indicative that the speedo needle is just stuck on its shaft. A tap on the case might release it. Otherwise, it has to be disassembled for repair.
If the cable were at fault, neither part would work, except in the case where the speedo is fluctuating, then that can generally be cured by lubing the cable and perhaps anchoring it down a little better
The obvious best solution for Jim is to get it replaced on warranty.
Bare