Hi,
How How to Check a 14v ran Power Adapter (whether it's die)?


Attached thumbnail(s)

looks like 24v for me

Ops, my bad, so sorry! It's 24v

Do you think the AC inputs connection on Board to the Pin of the Plug was wrong?


Attached thumbnail(s)

AC is ok, they don't quite care.

So after measuring at the output, doesn't have 24Vdc?
just happen lately or since day1?

For AC --> DC converter normally rectifier gg
this is the typical sch (ignore the values) https://www.circuits-diy.com/wp-content/upl...m-Schematic.png

Wow... Appreciate your helpful information! 🤩
It was working perfectly in the pass 2 weeks. And just go south yesterday 😭

I did test the 24v output via multimeter, either no value or not a stable value. So I tried on my 5v charger , it's stable at 5v+-. That means multimeter is good.

You are E&E Expert! I saw an info mentioned about that this kind of power adapter mostly caused by Rectifier! But I don't really have no knowledge about that , in fact I wish to learn 🤩 Do you kind to lead me?

not expert, just co-curriculum.
Rectifier == 1N4007 from the picture.

OptionA:
If this adapter is cheap, i would suggest you buy new cause not worth the risk to play with 240V. You might cook yourself before you fix it.
Just goto any hardware shop and bring your end device with you if possible to test up.

If your end device is huge, just bring the adapter, they will able to find one for you.

OptionB:
If DIY is truly your route, from your description of <either no value or not a stable value> then yea, most likely is the rectifier, you just need to change that.
Normally it is something has 4 pins --> mind to take a picture of the boards (top and bottoms)?
Typically looks like this


internally:



you just need to measure it (without power on) using the diode sign on your multimeter (assuming using digital)


long story short refer to this

Alternatively, get a proper LED power supply. Those MW ones will last very long and meant for heavy duty usage.

I replaced many of my Synology AC adaptors with MW power supplies quite a while back.

Be sure to check the device input wattage before ordering. If the device required 60W @ 12V, it should be a 5A output.

If the power adapter is not producing the correct voltage, it is broken already. Your only option to replace it. Messing around with the components that are connected to 240v is dangerous especially when you don't know what you are doing.

That kind of power supply design isn't used much these days. They are big, heavy and inefficient.

Nearly all of the power supply these days are switch mode power supplies which are much more complicated than the design above. Some can accept a wide input voltage range(100-240v) like the one shown in the picture on the first post.
https://en.wikipedia.org/wiki/Switched-mode_power_supply

It doesnt worth fix it, if you doesnt have knowledge and tools for it.

You're risking to be electrocuted for trying to repair it, it might explode too

A 24v 5a power adapter can be bought around 20-50

This post has been edited by stupiak07: Mar 23 2023, 06:18 PM

oh. from black brick replace to meanwell lrs? cool

if you look at the initial thread, you will find a transformer there and i suspect the one IC beside the heatsink is the rectifier but without proper image, i cannot confirm

Transformers and diodes can also be found in a switch mode power supply.

The first picture in this thread shows that the power supply can take an input volltage of 100v to 240v. Assuming your circuit was using a 240v to 24v tranformer, it would only produce around 10V if it was fed 100v. Way too low to produce 24v DC.

Btw, can I fitted with below power adapter that wasted for so long in my drawer?

24V 0.6A




Attached thumbnail(s)

Whats your load power rating in watts? The above power supply only 0.6A. The 1st post one is 5A

Ya lo! I think 150W.
How to calculate?
In this case, the device might not be able to turn on with 0.6A power adapter, right?

W/v= ampere. . This 0.6a definitely not enough.

I see! Gain knowledge 😁
150w/24v = 6.25A ,am I correct?

In fact, the original power adapter only 5A, enough?

what do you mean whether its die? no output?

Powered On device not working