Quote Originally Posted by RepIsland View Post
It is a Daytona SS/SS Black Dial Diamond Bezel BPF A7750. I always assumed that they have a back up power source.
A 7750 movement is an automatic mechanical unit - no battery.
If you don't wear the watch it will stop after the power reserve is spent. If you are wearing it and the watch still stops, it could be that your wrist activity is insufficient to give it enough power, or the rota is not free to turn.
If you manually wind it (30-35 turns) it should run for 24 hours regardless, and if you are wearing it, it should keep going. Timekeeping is a concern at that rate and suggests issues with the movement, as no adjustment would compensate for that amount of loss.
However you say it loses time until you wind it up again. Do you mean that the timekeeping is restored after a manual rewind? If it does then it might just be that the low power reserve is the cause.
Try giving it a manual wind and not wear it and see how long it runs for. If it stops or loses significant amount of time within 24 hours then you will need to get a rep friendly watchmaker to sort it out for you. If it is still running and keeping time then the rota may be the issue due to a fault or your relative inactivity.