Psu 12V 5A outputs 2.3V

[Askic]

Hello electronics experts.
I have a problem with 12V 5A rxz-60W-dy switching PSU. Instead of 12VDC it outputs only 2.3V without any load connected. LED on the PSU lights RED.
Does anybod has a schematics for this PSU and in general if anybody has similar experience?

[budm]

Re: Psu 12V 5A outputs 2.3V

Please attach good clear straight shots pictures of the whole top and bottom side of the board using 'Go Advanced' so we can see what we are dealing with.

[R_J]

Re: Psu 12V 5A outputs 2.3V

Google search found this video https://www.youtube.com/watch?v=Ej9ck8JoE2s Is this it?

[Askic]

Re: Psu 12V 5A outputs 2.3V

Hello and thank you for the replies.
Attached please find the pictures you asked.
R_J, it is very similar to the PSU shown in youtube video, but it is not an exact model.

[televizora]

Re: Psu 12V 5A outputs 2.3V

Check the diodes and transistors for shorts. And first replace the small cap.

[R_J]

Re: Psu 12V 5A outputs 2.3V

What is the number on U1 The first 2 numbers are likely the part number followed by a date code (5?N62? I can't read it in the picture) Replace the small electrolytic in the primary next to D8? and measure the voltage across that small cap, that is the ic's VDD and will indicate the state of the ic

[momaka]

Re: Psu 12V 5A outputs 2.3V

+1 in regards to checking/changing the small cap on the primary side. This is the "startup" cap and it's not uncommon for them to dry out or go bad in hot power adapters like these, especially if the cap is cheap Chinese/Taiwanese one.

[Askic]

Re: Psu 12V 5A outputs 2.3V

What is the number on U1 The first 2 numbers are likely the part number followed by a date code (5?N62? I can't read it in the picture) Replace the small electrolytic in the primary next to D8? and measure the voltage across that small cap, that is the ic's VDD and will indicate the state of the ic

It is hard for me to read the part number, but it seems 63N623. I have measured the voltage over the small cap and it's fluctuating between 9.5 and 12VDC. I'll replace this cap and see what is going to happen next.

[R_J]

Re: Psu 12V 5A outputs 2.3V

Have you tried a small load on this power supply? like a small 12 volt lamp? it could be in burst mode due to lack of load.

That first number seems to be a "5" so I would guess it is similar to a XN1059 ic.
The changing voltage means the ic is trying to start but does not continue to run.
This could be due to many things, lack of load on the secondary being one.

[Askic]

Re: Psu 12V 5A outputs 2.3V

I have tried with a load and with capacitor replaced, but no luck. I have found TS431A to be in short circuit and will try to replace it when delivered from ebay.