[Kimo]

I just got this TV from a friend and I'm trying to set the time so I can use the on/off timers but every time I set it it's always 5/10/15 seconds behind/ahead is their a trick to setting it does it automatically change to the next minute when I'm looking at the time display on the screen pop up before the change or do I need to bring it up after the change to the next minute. I need help I need this time to be bang on can any one help