I have the following circuit.
The components with cross over them are not installed on the board.
I have made two boards and made a few measurement of the boards separately. Here is the result.
| board #1 | board #2 |
|---|---|
 |
 |
The result of board #1 looks OK.
The result of board #2 looks strange. It seems the soft start filter capacitor charges and discharges again and again, and the chip never works. What is wrong with board #2?