AIS Receiver

[tombi]

Hello,

Trying to fix this AIS receiver for a friend.

Powers up on 12V but not on USB.

The thing has a million PTCs on it. I figure out the upper one (marked C) goes open circuit when I power it up off USB.

I think the chip marked ZE below is a DC-DC converter. it is just above the microcontroller.

For the life of me I can't identify the damn thing from the marking codes. I've tried the marking code books, lots of google searches etc. I think the sideways 27t is some sort of batch/voltage marking code and it might be on-semi but I have no idea.

I know people probably hate these posts and someone will find it on their first google search but I am stuffed if I can.

Tom