I have an ipad mini model no.A1432 that I bought unaware that it was reported stolen can icoud be bypassed

This means the ipad is reported stolen by the owner and is being tracked.......the owner is the only person who can unlock it!
it is a security app, 'find my ipad' and cannot be unlocked without the apple id!

No .

You probably know this as you are able to replace a motherboard. The question is confusing. It sounds to me as though your saying your display light either stays on or comes on randomly, this is either a fault in the wiring or the soldering. You will probably have to go back inside the pad.

The quickest and easiest way would be to take it back to the store you purchased it from, and ask for some guidance. They must be pretty poor to have sent you home without showing you even the most basic processes relating to your iPad.

If they are unwilling or unable to help you, take it to your nearest Apple store. I'm pretty sure that even if you didn't purchase it from them, they'd most likely be prepared to give you a few minutes of their time to introduce you to the machine and how to get it going :o)

After you put in the wrong pass code 3 times, you only can unlock the iPad with the correct password, belonging to the Apple ID from what is only a part shown on the screen. If you don't have the passcode nor the password Apple assumes you are not the legal owner, and you can't use the iPad anymore. Just go back to your friend, ask him to unlock the screen, to wipe the content and reset the iPad to factory settings.
For that goto settings, general and scroll to the bottom line and press that. then the second line wipe everything. Again the login code is asked. but after that the iPad is empty.Your friend should also remove the iPad from his list of registered Apple equipment.

Change your apple store and iTunes password.
Open your Find my Iphone app and report it stolen.
Call or go to apple store and report this stolen.

This is a job for an Apple Genius. You will have to make an appointment online with a local Apple store.