We had a friend who had a sundance spa with the control panel saying sentry 850. He said that it was struck by lightning and he couldn't get it to work so he gave it to us. My husband looked at it and somehow got it to work. Everything seems to come on but for some reason there is a lock symbol on the screen of the control panel on the top. We have looked up the manual on the internet and tried the Display, Mode, Down within 5 seconds suggestion but it isnt working. What can I do to make that work????

Its a Sundance Spa Sentry 850. It is a 8 man spa with the feet jets and everything else so it was free and seems to work except for that.

Thank You!