I bought this power supply which have suddenly burned after I checked what was wrong I see that power transistor have been bad soldered.
So after that I changed what was dead it is circled in red and power supply works but problem is when I connect on 12V some device which takes about 5.5A power supply starts to heat up really badly. And it is 20A power supply so it should stand more than just 5.5A withouth heating.
After that I bought another one almost the same but have 30A 12V and when connect on it the same device which use 5.5A it doesn't get even warm.
Have anyone an idea what can be wrong with first, repaired power supply so it heats so much???
Largest transistor which heats up is STW12NK90Z.
The pcb shows an outline for hex-sided small transistors like the BC147 that I worked with 50 years ago. Then maybe this power supply design is that old.
The pcb shows an outline for hex-sided small transistors like the BC147 that I worked with 50 years ago. Then maybe this power supply design is that old.