I copied a circuit board, 7W switching power supply, line and the original circuit is exactly the same, that is slightly different alignment, no power after the output. I made two boards, are the same ask, ask the master, where is the problem? How to deal with?
You better stick your PCB map, so you can see if your wiring is reasonable, the switching power supply is very particular about the wiring,
In addition you can also on the power network, to the IW area post, you can get more professional guidance
General safety requirements of the primary level in the board to the distance of more than 3mm, for a 7W switching power supply, the size of the transformer is certainly not large, 1 and 2,5 and 6 feet of the distance is certainly less than 3mm, unless your sub The output is flying
IC is generally the auxiliary power supply is a problem, the relevant components to check:
R8, R9, Q3, Z1, D5, R14, and transformers. Finally, U2.
The main thing you want to look at the voltage of the IC VCC pin is not within its specified range, if the IC problem, if not, from the C1 positive step by step to find over.
There may be a transformer problem, you have measured the inductance of two transformers is the same, flyback switching power supply is the core to stay in the gap.
