The blue line to the left is the component that desoldered itself. The blue line to the right is the component that is raging hot.
I power the system with an 18650 and a 5V solar panel. The troubleshooting has been done with just the USB connected. I've done a little smt repair, some successfully, but I'd at least like to try or at least understand the failure. I have the schematic, but need the layout to know designator of the overheating components. I have not seen the solar panel give more than 5V even in direct sunshine.

My T-SIM A7670E SA quit communicating via USB. One chip desoldered itself and another 4 pin chip is excessively hot. I have the schematic but do not have any information layout information to know what the components are that desoldered and are hot. I'd like to try to repair this part as I have a couple of other T-SIM A7670E SA that have also failed.