Is my chinese PSU broken?

Hey,

I've followed instructions on the internet on how to set the maximum current of my PSU.

I've connected the + and - output of the PSU and started to set the max current, the PSU kept flashing and it was pretty hard to set the current, almost impossible.

It has stucked on 40mA and now i can't use it anymore, it keeps flashing (even when not shortened) and when I connect a laser diode to it, the laser flashes with the PSU.

Here is the video of it

https://docs.google.com/open?id=0B22kKKb9KljDS2Y2QzBmd1YydWs

Where did you get your instructions? You can't set the current unless you short the output. Easier to just start from zero. What brand is it?

Hard to know what the problem is without removing the cover and probing it.

Yes, i shorted it to set the current, until shorting it was working fine. It smells like there's something burned inside when I turn it on

The brand is "YaXun" but I think this PSU is standart because i've seen many brands stamped in this model

Your PSU should not smell like burnt electronics. The fact that this is happened has me more worried than your current stuck at 40mA. If I were you I would send it back and get a new one if possible or if you think you can fix it. Pop the top and post some pics.

Sometimes if I put a large load on my PSU. It won't draw any current at all. What I have to do is turn the PSU off, turn both dials to zero and start the PSU again. Though my PSU doesn't smell like burnt electronics.

I've tried turning it on and off already, I might be able to fix it but i think it's better to just return it.

I would say it sounds like you fried something. To me it sounds like a bad idea to just short the wires and turn up the current. Assuming your leads were low enough gauge they would heat up and dissipate the energy(essentially using them as a giant resistor) but if they were high gauge you would be directing that to a place of higher resistance inside the PSU which would likely be some printed circuit or weak component that would just cook it. Personally, I hook my PSU to my 3A test load which is also heatsinked and designed to absorb the wattage with ease so I know that the heat isn't being generated inside my PSU instead. Essentially I do with my bench PSU exactly what one does with a driver to set the current.

I would pop open your PSU and look around to see if you visibly see any damaged components. Keep in mind it likely has stored power so don't fry yourself. You say that you can smell something burned so see if you can find the source. You may be able to just replace a component and be back up and running.

Also, I hate heat(I build computers so I am heat phobic ) so I added two computer fans to my PSU on its third rail so this thing can run for hours at max without even getting warm lol. If you are not able to fix your PSU you may want to look into the one I use. Its a Mastech HY3005F-3 that I got off amazon for $200. It has two infinite variable 30V 5A rails and a third fixed 5V 3A rail. I also found this little guy that I saw someone on here using (was it DTR?) and is the reason I searched out the one I got and is a lot cheaper and smaller than mine is.

EDIT: If you can return that sucker do it. Don't open it or do anything inside it just return it.

@jeffreythe00
It sounds like your PSU has a resettable fuse that trips when it thinks its being shorted to protect itself. Which goes back to what I was saying about frying things when you short the PSU lol.

Apex, my PSU has a shortcut protection system, it should not fry even when shortcutted. I'll just return it and buy a mastech just like DTR's.

The problem is, there are no mastechs in Brazil, i'll have to buy one from ebay and wait one month for it to arrive.

(We brazilians can't buy from amazon, they rip us off on taxes and expensive shipping)

Ah, well good luck with the Mastech. For most laser use that smaller one should work prefect. I only got the big one so I can power a TEC and a fan as well at the same time, or anything like that. I am not sure of yours will come with the TL-16 banana plugs(test leads) or not so you may want to look or ask as mine did not.

Why don't you ask one of our members here to drop ship one for you?

Wow, for some reason I didn't think of that, duh. I would have no problem doing that BTW.

I would put a dummy load on power supply and use that instead of straight-up shorting it.

Usually if I want current control I'll just use a transistor circuit. That requires two outputs on the PSU though.

Yes and yes. Don't short the PSU use a test load like you would a laser driver. Building a driver for the PSU works well also but it isn't needed with the PSU as long as you either turn the power up very slowly until you reach the current you desire or you turn it up on a test load and then hook up your diode once its set.

Either way, you can pretty much plan to never short the PSU again. Especially if you desire to have it work for any extended time.

For real one of you could re-ship it for me? That'd be great!

I've found a cheaper one on amazon:

http://www.amazon.com/Mastech-Varia...e=UTF8&qid=1354935606&sr=1-1&keywords=mastech

ApexProxy said:

Either way, you can pretty much plan to never short the PSU again. Especially if you desire to have it work for any extended time.

Click to expand...

Bench power supplies are designed to be able to drive a short all day long.
Quit feeding the poor lad bullshit.

Once again... bro you really should work on your social abrasiveness. There are ways of saying things without sounding like... well that right there actually.

Even if you are right and they are designed to handle it, its still not a good idea no matter how you look at it and regardless you are better off using a test load. Even if it can doesn't mean its good for it in the long run.

Sure I could have said "I'm afraid you're mistaken, kind sir" with 5 smileys, but it's not my style, and it's rather boring. I think it's more disrespectful to misinform someone, and then defend yourself for doing so. If calling bullshit bullshit is "socially abrasive", then I'm the community sandpaper.

ApexProxy said:

Even if you are right and they are designed to handle it, its still not a good idea no matter how you look at it

Click to expand...

Here we go again...



That doesn't even make any sense. Next you're gonna tell me that even though a light bulb is designed for 120V, you shouldn't plug it in to 120V socket?

ApexProxy said:

Even if it can doesn't mean its good for it in the long run.

Click to expand...

Only in the sense that using something puts wear on it. But that's true of everything in existence.
You could also say driving a car isn't "good for it in the long run." Does that mean it's reasonable to expect others to never drive cars and keep them under a tarp?
Running it at 0V really isn't any harder on it than running it at 3V. They don't care. They can take it all day long and not complain the least bit.

If you don't know anything about bench power supplies, don't comment. Don't transfer your knowledge from dime-sized drivers and assume everything operates the same way.

You're starting the conversation from a loosing position and refusing to listen - attacking my wording rather than the facts. That's not science, that's politics.