How to distinguish the power supply adapter

Today, I got 2pcs power supply adapter from 2 different supplier

Out of curiosity, I unassemble them.  Found they power supply module is quite different.

The one is bad , PCB is old , a lot of glue on the board, and there are lots of dust on the PCB, if the glue loose and two parts touch each other, it will cause fire

Below is the good one, PCB is new and clear, there is no glue