Flyback switching power supply

Attached video:
When powering on without load, it should be far away. The 12V is stable, but there is no load. I don’t know what the situation is.
Winding method:
1. First wind the primary end of the transformer with the same name
2, and make a circle. When one layer is full, you need to add tape. First fix the enameled wire to a section
3, tie it with tape once, and then wind it, because it is not enough for one layer. , you can wind it sparsely. After finishing, use the other side of the primary to take out
4 and tie it once with tape. The primary side winding has been wound around
5. Next, wind the secondary winding. The calculation here is 5 bundles. It is inconvenient to solder on one pin and it is difficult to wind it.
Separate it into two pins, 3 and 2 respectively, and then wind
6 together. The fourth round of winding here will be a full layer. Apply the tape and continue winding.
7. After completing one winding, divide the 5 bundles of enameled wires into 3 and 2, just like the same end of the primary winding at the beginning,
and finally wind a layer of tape
8, so that the primary winding is completed, and then wind the auxiliary winding
9, the auxiliary winding Go around 6 gates. If there is less than one level here, go around as evenly as possible.
10. Finally, scrape off the insulation on the surface of each enameled wire, tin it separately, and finally wrap it on its own pin.
11. Take out the magnetic core and stick it on the frame.
12. Just like this.
13. Finally, wind it with a few wires. With just a few layers of tape, a transformer is completed.