I've been having some issues with my MK Terrova.
Several issues I'm having are (and this has been going on for a while now)

*Spot lock seems to be moving. Let's say I'm spot locked 15'-20' from a stump. After a while, I notice I'm right next to or darn near on top of the spot I'm trying to fish or I'm even farther away.

*Spot Lock just seems to turn off. At first, I thought maybe I hit a button or somehow I accidentally turned it off but I really don't think that's the case. Sometimes it holds for quite a while, sometimes it happens in a few minutes.

*Remote loses or erases saved waypoints. If I save a waypoint, it MIGHT stay saved for a little while but I noticed it will eventually disappear. It may be there for a little while but it's never there 3-4 months later. FYI, I always keep my batteries fresh in the remote, I generally change them when i see and drop from being at full charge.

It's the newer version Terrova and is 4 years old. I'd like to get these bugs worked out, especially the on/off issue and the moving issue.
I have been playing with the boat scale settings and that doesn't seem to help much.
I've been looking for a way to delete or erase everything off the TM and start all over again. I'd guess you'd say I want to restore defaults and go through the set-up procedures again and see if this helps, but I can't find any way to do it.
Is even possible to restore to factory settings.

Any ideas before I go to a repair shop to try to figure this thing out?
Thanks in advance for any help I get.