Do you have an LCR meter to measure inductance? The only other reason for the output being wrong, assuming the chip isn't faulty, is a wrong inductor value - maybe it has an internal short.

So, the green inductor should be 1000UH, I get reading for it 966.7uH and 5.5ohms

The black one should be 1.6MH, I get reading 1.6mH and 1.6ohms

 

I have replaced the green inductor, and the issue still persists... At this point, I will desolder everything, and test each component individually

 

Here is the board without components

 

okay, I tested these components individually with Fnirsi LCR-P1

Component	Tested with LCR-P1
3x 104	106, 95,101
Inductor 1000UH	Val:5.6Ohm L:952.5uH
Inductor 1.6MH	Val: 1.7Ohm L:1.6mH
Cap 4.7UF/400V	Vloss:0.5% esr: 2.47Ohm Cap 4.1uF
Cap 4.7UF/400V	Vloss:0.4% esr: 2.53Ohm Cap 4.2uF
Cap 470UF/25V	Vloss:1.6% esr: 0.11Ohm Cap 459uF
Cap 10UF/50V	Vloss:0.3% esr: 1.48Ohm Cap 10.0uF
Cap 223J	20nF
FR107	Vf:637mV Ir:5.7nA Cap: 10pF
BYC26	Vf:572mV Ir:5.1nA Cap: 10pF
Cap 1.6MH	82nF
10K471	220pF

 

What are the markings on the yellow square capacitor measuring 82n?

Updated schematic based on latest info:

 

What are the markings on the yellow square capacitor measuring 82n?

Updated schematic based on latest info:

View attachment 363947

x2-104K MPX/MKP

 

x2-104K MPX/MKP

And I still don't see why it outputs way above the designed voltage... :|

 

And I still don't see why it outputs way above the designed voltage... :|

I have to say that, right this moment, I don't either.

I don't suppose you have an oscilloscope?

 

I have to say that, right this moment, I don't either.

I don't suppose you have an oscilloscope?

No oscilloscope... This board looks so simple but it's a hell...

 

Also, when I attach the 2k resistor at the power for control board, voltage gets static at 15V..

 

Hi, when testing SMPSs make sure there is a load. Is it possible that the power supply board is not being loaded properly and the failure is elsewhere(?) ...just an idea!

 

I have also found this typical circuit for PN8024R:
View attachment 363868

I will try to make this circuit from the components from this board, and see will it output 12V...

 

Also, when I attach the 2k resistor at the power for control board, voltage gets static at 15V..

That's interesting... it should regulate all the way down to near zero current... maybe it needs a minimum load current to regulate. There's nothing in the datasheet to indicate that, though it does show a 2k bleed resistor on the example circuit.. Try a 1k2 1/2W resistor.

 

That's interesting... it should regulate all the way down to near zero current... maybe it needs a minimum load current to regulate. There's nothing in the datasheet to indicate that, though it does show a 2k bleed resistor on the example circuit.. Try a 1k2 1/2W resistor.

This outputs 15V... instead of 4.7uF/25V i put 10uF/50V because I dont have 4.7/25V, and instead capacitor 333, i put 2A223J green capacitor

 

This outputs 15V... instead of 4.7uF/25V i put 10uF/50V because I dont have 4.7/25V, and instead capacitor 333, i put 2A223J green capacitor

But it should be outputting 12V or I am missing something?

 

This outputs 15V... instead of 4.7uF/25V i put 10uF/50V because I dont have 4.7/25V, and instead capacitor 333, i put 2A223J green capacitor

Not seen a circuit built like that for many years!

But it should be outputting 12V or I am missing something?

What value is the load resistor? What happens if you make it smaller, ie put another similar in parallel?



Latest schematic with all components now identified:

 

Not seen a circuit built like that for many years!


What value is the load resistor? What happens if you make it smaller, ie put another similar in parallel?



Latest schematic with all components now identified:

View attachment 363986

Haha, That is what I have!

I put 2.2k resistor,

I replaced 2.2k resistor, and now its 12.3V

 

Haha, That is what I have!

I put 2.2k resistor,

I replaced 2.2k resistor, and now its 12.3V

I replaced it with 1K

 

Seems it needs at least 12mA load to regulate.. According to the datasheet it should be able to output 500mA at 12.3v. Have you any smaller value resistors, in the 100-500ohm range, to put in parallel make around 80 - 100 ohms, so we can prove the chip is actually regulating properly...

 

Seems it needs at least 12mA load to regulate.. According to the datasheet it should be able to output 500mA at 12.3v. Have you any smaller value resistors, in the 100-500ohm range, to put in parallel make around 80 - 100 ohms, so we can prove the chip is actually regulating properly...

so in theory, that small electrolytic capacitor should act as a load on control board, let me replace it and test it