Found my problem, broken prong on the power connection but Marcum won't sell me the part. They say I need to send it in, can't bring it in because of Covid, so $99 plus shipping. I found the part online for $4.50. Thanks for the thoughts and comments.
Not to dampen anyone's enthusiasm for fishing Minnetonka, but I have been fishing it since the late 60s. Even in normal winter's (whatever that is) there can be bad spots away from shore due to springs or schooling fish and the channels can be sketchy too. Many times there are pressure ridges at the mouths of the channel than one can break through. Just ask my dad, and he was walking. If you're set on Tonka I'd suggest picking an area of the lake with large bays so you wouldn't have to go through a channel or it would minimize the number of channels you went through. Now if someone has been out this winter and knows it's safe that's a different story or if you check the channels before you go through them. It's a fun lake to fish year 'round but especially in the winter. There are a lot of fish in it.
Skunked- The areas of Black lakes seemed very similar to Black Bay. Flat 6 to 7 feet deep. I did have a friend years ago take his fish and ski into Black Lake. He said it was interesting getting in there. Do you ever see signs of winter kill in Black Bay? I thought I recalled something about one 7 or 8 years ago.
Good Luck - Enjoy every day