I have the same one and i am satisfied. Its all about knowing how to use it. It is lowering the voltage. This power supply is good for finding short circuit and its stable for the price it has! Indeed it has not a shortcut protection but its fine!
@@emanuelmilani7976 under loading it gives you the option to change current and voltage. Sure if you go at full current the voltage will drop like a short protection but with lets say 3 amps you can adjust both amps and voltage!
Yes. But if can select this modes the ps can decrease amper in one mode and voltage in the other (I think some other ps can do this) My question is... This ps can change mode?
@@emanuelmilani7976 of course you can change voltage and amp at the same time but at full loading you cannot change voltage. It is like protection. You can check for video reviews about this ps on youtube from other users.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
@@uni-bytebecause he tries & often succeeds, when others would give up, that is how science was worked out in the first place, of course many experimenters died on the way. Look at deaths associated with the Manhattan Project!
i read so many comments trying to explain to a man (who knows more about electronics than all of us) how a power supply works trust me he knows the problem is he paid for something and he got something else!!!!! there is not short circuit protection on this think thats the problem......... this is sad
Sorin tried to offer the idea behind the missing short circuit protection. It should stop at the moment when there is one and allow current flow after it's gone + after a time period set by the manufacturer in N seconds during which it will test itself for problems. I think it is normal a specialist in electronics to expect his/her lab supply to protect itself and things connected to it when a short is detected, not to continuously draw or provide a current. It must stop and allow to be started again only when that short is found and removed
People Sorin is great man he help us a lot can you imagine to work every day with those electronics...its hard so what if he made a mistake...Keep it up man and thanks for all !!!
That's normal. This device has tow ways to control it's output, voltage control when the right light is led and current control when the light on the left is led.
Sorin, there is nothing wrong with it. This is how you set your constant current limit, by shorting the cables at a low voltage. All modern power supplies do this. Turn your amperage down to set it lower.
@PVJ No. This is a general feature for that cheap PSU. It is limiting the current what u set it up before. Than, stops more current flowing over what u set,in a shorted case. So ur board safe, just think before u use it, what is the current setting.
@PVJ So, that cheap PSU has only an overload protection, not more. U can use it, but be careful with it. Set the current settings down like 5-20mA, when u start to work. But better an also cheap (for example Korad KA3005D) has a button for turn on, off the short circuit protection as u want, or for every time use it on. Good for motherboards.
@PVJ - These PSUs are OK for diagnosis/repair - you just have to be careful when using them. Sometimes you _want_ to disable automatic shutoff, like Soren did to one of his older PSUs, most of the time, you want it on AFAIK.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
@@albertogog8567 Yes it will.....but you need to short the leads first to set the max amperage you want to inject, otherwise it will burn the component. Maybe set 1 amp or something low.
Yes, it *DOES* have a short-circuit protection. The red light is telling you that it is in protect mode. You can set the limiting current by shorting and then rotating the current knob just above the "CC" on your power supply. Sorin, you are good at what you do but there are a few things we are glad to share with you. Keep it up, bro.
I am sorry...my comment was deleted.... i understood voltage limiting while we had, in reality, voltage drop due to excessive consumption....you are right...thanks to take your time to explain us
@@jeffescortlx I'll see if I can get a j02. I just got the iron so I'll see how good it works, i knew the k was good for wicking so this confirms that. I did not know about the j02 so thanks for telling me about that one
Power Supply should disconnect the voltage when it gets short. this power supply is constantly providing the power in short circuit. a normal Power supply disconnects when + & - points are short together. he wanted to show us how to modify a normal power supply to provide amps in short circuits to check the short components. but unfortunately this new power supply was already doing the same thing which he wanted to modify. so it is a defected PSU.
@@sikandarkhan-gb2nw I have experience with 4 different bench power supplies manufactured within the last 5 year's. They all have constant current mode that continues to work while shorted. If you set it to 2 amps, it's going to push 2 amps. If you set it to 5 amps, it's going to push up to 5 amps. The advertisement is maybe misleading with listing short circuit protection. It's probably internal protection if something fails in the regulation circuit. I'm guessing a thermal switch or fuse on the transformer.
It is absolutely normal whit those power supplies. Your leads have resistance 0.1 ohm and power supply is limiting current to 5A so you have 0.5V. I have used tons of them. Itis probably just a problem in the description. If it has short circuit protection than you can do proper testing. Actually, I have never seen one with short circuit protection. How many Ohms is short circuit for you? And if you need one with the thermally controlled fan you need to spend a little bit more than £40 on PS.
Hi there! I think Sorin isn't wrong, he just wanted to make a video of how you hack a power supply and remove the current protection so you can check for shorts on laptops. Because if there is short protection on the power supply it will cut the electricity to protect the supplied electronic but also the power supply itself. The cliking noise Sorin refers to is when a "legal to sell" power supply cut the electricity. As he mention a power supply MUST have current protection from European regulation. You can't sell power supplies within Europe without protection. But this new power supply had the current protection already removed so there is nothin Sorin to do. This power supply is "illegal" in Europe but ready for us to work with Sorin's style!! ;)
I believe that is incorrect. There is a fuse in the plug no? If so, it is current protected to maximum of the fuse, meaning it does follow European regulations and can be sold. Besides a shorted cable will draw more than 5A, but we never see it draw more so it is limiting the current. If it draws more and blowing the fuse then it would be illegal.
That PSU is perfectly acceptable to use as a means to detect faults without modification. Lets say i have a circuit that normally pulls 2amps at 12v with a suspected short. I would set the PSU to 12v and 2 Amps. If the circuit has a short it would drop the voltage close to 0 but still pull 2amps. This would still protect the circuit because the PCB is desgined around 2amps. If you mod the PSU to bypass the constant current feature, the said circuit would probably catch of fire! I believe he does not understand basic electrical theory. I would be worried sending my laptop to him to fix.
I have the same Power Supply and I can confirm that it has a Short Circuit Protection. Even though is showing the Amps is not actually out putting anything. It's showing there so you can limit the current. I've tested with a load (lamp) and as soon as you short it the light goes off meaning the PS is cutting off. Perhaps Sorin could do a video disabling the SCP on the PS. I'm desperately waiting for this so I can learn it.
hi sir I am just a beginner. I just want to ask if using a power supply without short protection for troubleshooting shorted parts on motherboard will get damage in the long run?
This kind of power supply is used to identify possible short circuits by heating components. Very useful indeed. you can set the current to low if you want protection or higher if you want controlled heat to build up. A thermal camera is often used to spot the heated component.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
I have the same model and it does the same thing. Thought it was normal and it was 😊. The fan works when using Higher voltages, but with a well cooled room your not gonna be having any problems
@@NeuronalAxon By using the adjustment while 'under load conditions' to get a more accurate setting of current control. Sort of like when you get a voltage drop when using a switched mode power supply (electronic transformer) the output can be many more volts just taking a bare measurement than when you are actually powering something. Hope that makes sense.
@Arnold Rimmer Read it again Arnie. Brian was saying he shorts his PSU to set the current, not test for short. He has shorted it on purpose FOR a purpose, not to diagnose whether a fault exists via a short.
@Arnold Rimmer Its not about being used for testing for short, also in design you may not know the demand for current. In an ideal world a circuit would control this, but what about an oversight, lets say an LED without a resistor. That baby will suck as much current it can until it destroys itself. We could just put a fuse inline and rely on that but it's also not accurate. A bog standard 13A fuse will quite happily run for hours at 16A without blowing. So back to what has been said before, assuming the indicator is actually at your setting under short without having a 20% ir whatever tolerance, I would set my PSU the same way with a short. I would also check it inline with another meter to see how close it actually is, lets call it a homemade callibration.
You should probably read the manual first... You can set the current limit with the current nobs when the leads are shorted. You can set the voltage when the leads are not shorted.
Thanks very much for your time and good work keep it up your REWARD is in heaven !!! #. I want to know; What type of phone heater and air compressor are you using ?
CC means Constant Current.... that is the current stays constant even in a short..... that is even if you had a superconductor at 0-ohm, a 5A limit is 5A.... it will apply a voltage across the conductor for 5A flow (in the case of 0-ohm the voltage will be lost across the power supply internals). The voltage is supposed to drop as per V=IxR where I and R is fixed and thus the V follows. This CC mode is how I manually recharge Lithium batteries.... set max voltage, set safe charge current.... hook up batteries, charge. When nearing 4.2v per cell it is advisable to supervise the batteries... For circuit diagnosis, set to about 800mV (1v should be OK) as sensitive circuits may be down stream of the circuits.... this can help locate the short by literally heating up the faulty component (unless said component behaves like a wire.... then educated guessing applies). CC mode is super useful.... having a current limit cutout means you could've applied, maybe up to 30V and 5A for even a fraction of a second.
so this is the best powersupply to find short circuits because you have nothing to modify right? it will work just out of the box and we can follow your lessons with it right?
Hi sorin, I'm a very good fan of your Chanel and I will like to specially thank you for your good work and for all the effort you put in uploading all those educative videos. I must confess, your videos has helped me alot in my repair business. As a matter of fact, I have more than 80% of your videos downloaded on my device. But dear Sorin, I will love it if you can do a video on How to disable SHORT Protection on a power supply. I recently got a new power supply ( 1502DD series) but it's seriously limiting my work becos I can't use it to find short on any shorted iPhone. Thank you so much for your contribution and help towards my successful electronic repair business. ....................Your very good fan from NIGERIA.
Good video. Thanks for sharing with us. This power supply it is dangerous. 0V 5A its shorts circuit eventually it will burn. Don't forget to check every day if its not on short or off before leaving. Like you said, left the producer with defect :D
you mean if it had short circuit protection....which it doesnt... you could still find your short as it would unexpectedly switch to 0 amps...when you expect it to be taking amps..that identifies your short on a short circuit protected power supply.... the psu has overload protection...you can restrict the current with the nobs...
I really love your videos Sir. you are really doing a great job. please, i would love you to do a video on how to use a Power supply in PC and Smart phone repairs,. and also, Understanding a multi-metre for beginners. I've watched many video's concerning this on RUclips, but none of this video's has made me understand how to use these equipment's.
I have pretty much the EXACT same cheap chinese power supply. Its constant voltage UNTIL you hit the current limit that you set. The fan noise of mine is near silent until you short it. Once shorted, it cranks up the fan speed (which it would need to do to get rid of that heat) One thing I wish it could do would be to show what the current limit is set at (without having to short it first)
To everyone confusing 'short circuit protection' with 'current/voltage control/limiting'... The issue is that Sorin thinks the PSU should cut-out in the event of a short circuit but when he shorts the wires the unit keeps supplying power. He fully understands what current/voltage limiting is, that is not the issue here. I am no expert but I think that the short circuit protection he is looking for is internal - ie the unit will cut-out in the event of an internal short but not due to a low-resistance-load short of the type Sorin created?
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
I have the same but different company name! What I first did is put it low cost temperature sensor for a fan, because it is too loud. When you make a short it get hot really fast!
maybe if he presses the STOP/OUT BUTTON..then it switches into short circuit protection mode rahter than constant current or constand voltage mode.....otherwise it broken as the voltage of say 10 volts is reading 0.4 ...which implies that the potential difference between live and ground is zero due to shorting...but the current is still flowing....and the manual said that it has short circuit protection...which it hasnt ..it has max current limiting...but no short circuit protection. had it got short circuit protection..then when the voltage drops from 10 volts to 0.4 volts implying a short circuit as potential difference between live and ground is now close to zero....the current should stop flowing ....this is short circuit protection.... on his unit current keeps flowing...and if he left it for an hour ...would mean fire....not only that woudl melt plastic leads....would burn out chips in the device.... would have to buy new device...and also new house that burn down. this is not short circuit protection. your child messes with electronics.....leaves leads touching and goes out to play...next thing house burn down.... no short circuit protection... you must be bloody stupid to think it is short circuit protection...also on delicate logic circuit ..you can blow chips with just little touch accidentally if short not protected.
@Arnold Rimmer mostly correct ha ha..i just educated you as to what current limiting protection is and short circuit protection..and you answer like you taught me something...ha ha you funny guy.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
Those protection maybe design for internal circuit, not for the output of the power supply. And that power supply require you to shorted the prob in order to set current limit.
Let me explain: CC constant current, CV constant voltage, OVP over voltage protection, OCP over current protection. That PSU only has CV and CC. If you want one with OCP and OVP you need to pay a little more :)
so its already jailbroken 😔 I have this type of power supply too, if you short it you can adjust the current, but as i understand if you put a device that draw 1amp like a fan even if you set it to 5amps it will only draw 1amp, so its a protected?i thought removing that limit force supply to send full 5amp, thanks again for the video 👍👍👍
that's normal, connect +ve to -ve, set your current limiter using the current knob. then disconnect, now on you can't exceed the current you set, when exceeded red led will be ON.
I’m surprised that you are surprised... This is the model 305, meaning, I guess, 30v 5A max. So what are you expecting from a short? 5A, 0volts of course...
I thought you would want this feature for your brute force method!? I have this exact same one and operates the same. Did you have to modify your other power supply to behave the same way or something?
It's just like when a math-professor makes a simple error like 2+2=5 :D Every student can see it, so everybody is laughing and pointing. Forgive us Sorin, we still respect you highly for your great videos, experience and amazing knowledge.
Hello Sorin I have exacly same power supply. But soz Im begginer Im scared to use it at all. Can you show how to make short circuit protection for this one?
5 Amps but almost 0 Volts. You have no sparks when you touch the two probes. The user manual indicate to short the PSU for tune the amps, and after you need to unshort to tune the voltage. I think this is a feature. Try to have 2A 2V like in your videos on a faultly MB, per example. It's impossible. The voltage will bringing down to 0.0x
In all your troubleshooting video with a short circuit issue. You always inject voltage in the circuit and find the component that gets hot. You always show us the current goes high while the voltage went down. Now you did the same, you short the output. Current goes high while the voltage went down, and you now you will say power supply is faulty? Whats the difference?
I have the exact model for 3 years and sometimes it runs for 3 4 hours giving around 2 amps constantly and still works like a dream, I put a resistor on the fan and it's much quieter and barely warm after a few hours.
It is short circuit protected. It's limiting the current to what you set it AT and it will not exceed that. It is doing exactly what the specifications say it should do and exactly what it's supposed to do. What were you expecting it to do? It does not have "over current protection" but you would not expect that on a budget power supply. You know, sometimes it's up to the user to do the sensible thing. If you attach the power supply to a circuit that you expect to draw 1A and you set the supply to 5A you are an i???t. Seriously, what do you expect it to do?
Sorin, you turned the current limit up from 4 amps to 5. And complained. Not a single attempt at turning it the other way. Can you hear the viewers screaming at you?
I think he is hiding and kicking himself. Perhaps in hindsight he would have watched his own video back before posting it. I am sure he would have spotted it. I was questioning myself while watching this if I had started forgetting shit from the past but still screaming at the TV to look at the BIG red numbers on the display.
I have seen a couple of short circuit protection videos, isnt a matter of opening the piwer supply and seeing if the large eg 100watt protection resistor has been jumpered? Might be a lesser value for lower max current supplies.
Mine cuts out when the unit itself can't handle the MAX current BUT this current can only be reached if potentiometer is changed inside the machine to above the set value this unit comes with, therefore allowing the unit to go above 5 amps. My unit can handle 6 amps therefore mine is within the range
It's not faulty IMO....it's in Constant-Current at that point, so it brings the voltage down to maintain the current you set, since it can't tell the difference between the wires being shorted and, say, a "true" 5A load.
Yes! he is misunderstanding how it works. The only way to control the Power going to a circuit, is to modify the voltage, or the current. P (power) = I (current in A) x V ( Voltage in volts). The current is a function of the resistance in a circuit and the voltage applied to it. ( I = V / R ) , so if you want to limit the current, with a set resistance, you HAVE to lower the voltage. You could add resistance into the circuit, but it's the same effect, as you have just created a resistor divider which also lowers the voltage, by dividing it between two resistances. This PSU lets you set the current limit, and it will supply the set Voltage, till you reach the current limit, then it will at that point switch from constant voltage mode, to constant current mode, and reduce the voltage to stop the current from changing. You can only fix one part of the equation. If you want a constant current, and the resistance is changing, the only thing left to change is the voltage, to keep the current constant. As soon as you fix the voltage, and the resistance changes, the current HAS to change.
Just a simple mistake guys go easy. Nothing can refute the fact the guy knows his craft and trusts his instincts... maybe too much and it's in such cases that one makes such errors. Thanks for the video sir I know you later on figured it out.
@@TechbayElectronicsRepair You said he made an error three times in you message, when he didn't. I don't get what point I missed. You are wrong, Sorin is the supreme electronics god.
Sorry for you Sorin, This time, you're wrong! The power supply is working fine! It works just the one on my bench! The power supply is regulating the preset current (5A) adjusting the voltage... You can regulate how much current you need, rotating the current knobs on the left, in the front panel! Maybe the one you have on your benchtop works differently, but all the power supplies I ever had (also HP, and other hi-valued supplies works like that... So, I think your power supply works fine (with no "click" ok..) but I'm used repair with a power supply just like the one you are showing, setting the shor circuit current BEFORE i actually apply it to the circuit...
Hello Mario. What kind of values do you use for the current when sorted (set up mode), and after for the voltage when unshorted. I means, the values of A and V to find a short on a motherboard. Thanks for your reply
@@poloemilien4858 If you mean the Voltage/current injection procedure Sorin does, it is very simple: If you are checking the 19V Power rail, you set 19V on the power supply. If the 5V, the 5V, etc. For the current, you short-circuit the power supply terminals and start with few mA. Then you connect the ground terminal first and then the Positive terminal. Then if there's a short, you can see the current you just set-up on the Power supply display. After you can try to raise the current, acting on the CURRENT KNOBS very slowly, trying to find the component who will become HOT (using some Petrol or Isopropylic Alchool). *Follow the procedure that Sorin uses in most of his videos*, and *BE CAREFUL* not to touch anything else, or you will destroy other components non related the fault you're investigating. Hope this will be clear enough. Ciao. Mario
In same way with this psu, when i want to put 1v on laptop motherboard, often i can't control current, can you tell me if it's normal? feel it sometimes useless. Thanks
Sorin welcome to constant current mode which is a protection since you can't go over the PSU max current or your own set current :) electronics are wonderful aren't they ? … for what you do , injecting external current into shorted components, using either smps or linear PSU is the same. Linear PSU are used in circuits where low noise is required, like for example , quality audio amps.
You could get a fancier fan that fits the hopefully standard-sized fixings on the PSU, and/or just put a resistor inline with the existing fan cable to slow it down.
@@NeuronalAxon I do not think it is a good idea. If u reduced the fan speed, u can burn ur psu. u may use a bigger and better profiled fan, not just a slower one - I think.
@Arnold Rimmer Yes, u are right. Mine one do it well in 0-100% auto, I just told to Neuron, if he want to using a fix resistor is not a good idea to slowing down the fan, because on max power, the PSU will need max air flow. The less could burn it.
I have the same one and i am satisfied. Its all about knowing how to use it. It is lowering the voltage. This power supply is good for finding short circuit and its stable for the price it has! Indeed it has not a shortcut protection but its fine!
But this one can switch from constant current to constant voltage?
@@emanuelmilani7976 under loading it gives you the option to change current and voltage. Sure if you go at full current the voltage will drop like a short protection but with lets say 3 amps you can adjust both amps and voltage!
Yes. But if can select this modes the ps can decrease amper in one mode and voltage in the other (I think some other ps can do this)
My question is... This ps can change mode?
@@emanuelmilani7976 of course you can change voltage and amp at the same time but at full loading you cannot change voltage. It is like protection. You can check for video reviews about this ps on youtube from other users.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
its called constant current mode... its not broken that's how it functions. most every power supply I've ever used worked like this.
EXACTLY
Yes. Why do so many people like this guy?
@@uni-bytebecause he tries & often succeeds, when others would give up, that is how science was worked out in the first place, of course many experimenters died on the way. Look at deaths associated with the Manhattan Project!
i read so many comments trying to explain to a man (who knows more about electronics than all of us) how a power supply works trust me he knows
the problem is he paid for something and he got something else!!!!! there is not short circuit protection on this think thats the problem.........
this is sad
Sorin tried to offer the idea behind the missing short circuit protection. It should stop at the moment when there is one and allow current flow after it's gone + after a time period set by the manufacturer in N seconds during which it will test itself for problems. I think it is normal a specialist in electronics to expect his/her lab supply to protect itself and things connected to it when a short is detected, not to continuously draw or provide a current. It must stop and allow to be started again only when that short is found and removed
People Sorin is great man he help us a lot can you imagine to work every day with those electronics...its hard so what if he made a mistake...Keep it up man and thanks for all !!!
Yeah exactly nobody can be right all the time
That's normal. This device has tow ways to control it's output, voltage control when the right light is led and current control when the light on the left is led.
Sorin, there is nothing wrong with it. This is how you set your constant current limit, by shorting the cables at a low voltage. All modern power supplies do this. Turn your amperage down to set it lower.
@PVJ No. This is a general feature for that cheap PSU. It is limiting the current what u set it up before. Than, stops more current flowing over what u set,in a shorted case. So ur board safe, just think before u use it, what is the current setting.
@PVJ So, that cheap PSU has only an overload protection, not more. U can use it, but be careful with it. Set the current settings down like 5-20mA, when u start to work. But better an also cheap (for example Korad KA3005D) has a button for turn on, off the short circuit protection as u want, or for every time use it on. Good for motherboards.
@PVJ - These PSUs are OK for diagnosis/repair - you just have to be careful when using them.
Sometimes you _want_ to disable automatic shutoff, like Soren did to one of his older PSUs, most of the time, you want it on AFAIK.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
@@albertogog8567 Yes it will.....but you need to short the leads first to set the max amperage you want to inject, otherwise it will burn the component. Maybe set 1 amp or something low.
I just bought that power supply last week! When you replace the fan with a heatsink, please do a video on it Sorin!
Yes, it *DOES* have a short-circuit protection. The red light is telling you that it is in protect mode. You can set the limiting current by shorting and then rotating the current knob just above the "CC" on your power supply. Sorin, you are good at what you do but there are a few things we are glad to share with you. Keep it up, bro.
I am sorry...my comment was deleted.... i understood voltage limiting while we had, in reality, voltage drop due to excessive consumption....you are right...thanks to take your time to explain us
The power supply is doing exactly what it's supposed to do. It's a 5 amp capible power supply set to 5 amps. It's going to push 5 amps.
Good to see you. I bought one those oled soldering station's. What pen types do you like, I currently have the t12- ILS and t12-K
@@momfiethehunter504 T12-J02 for general purpose and K for wicking and big stuff. With Micro quick change handle.
@@jeffescortlx I'll see if I can get a j02. I just got the iron so I'll see how good it works, i knew the k was good for wicking so this confirms that. I did not know about the j02 so thanks for telling me about that one
Power Supply should disconnect the voltage when it gets short. this power supply is constantly providing the power in short circuit. a normal Power supply disconnects when + & - points are short together. he wanted to show us how to modify a normal power supply to provide amps in short circuits to check the short components. but unfortunately this new power supply was already doing the same thing which he wanted to modify. so it is a defected PSU.
@@sikandarkhan-gb2nw I have experience with 4 different bench power supplies manufactured within the last 5 year's. They all have constant current mode that continues to work while shorted. If you set it to 2 amps, it's going to push 2 amps. If you set it to 5 amps, it's going to push up to 5 amps. The advertisement is maybe misleading with listing short circuit protection. It's probably internal protection if something fails in the regulation circuit. I'm guessing a thermal switch or fuse on the transformer.
It is absolutely normal whit those power supplies. Your leads have resistance 0.1 ohm and power supply is limiting current to 5A so you have 0.5V. I have used tons of them. Itis probably just a problem in the description. If it has short circuit protection than you can do proper testing. Actually, I have never seen one with short circuit protection. How many Ohms is short circuit for you?
And if you need one with the thermally controlled fan you need to spend a little bit more than £40 on PS.
You've never seen one (a bench power supply, I'm presuming?) *with* short circuit protection, or did you mean to write *without* ?
@Arnold Rimmer how power supply know answer to your question?
@Arnold Rimmer - You failed engineering, Rimmer.
Hi there! I think Sorin isn't wrong, he just wanted to make a video of how you hack a power supply and remove the current protection so you can check for shorts on laptops. Because if there is short protection on the power supply it will cut the electricity to protect the supplied electronic but also the power supply itself. The cliking noise Sorin refers to is when a "legal to sell" power supply cut the electricity. As he mention a power supply MUST have current protection from European regulation. You can't sell power supplies within Europe without protection. But this new power supply had the current protection already removed so there is nothin Sorin to do. This power supply is "illegal" in Europe but ready for us to work with Sorin's style!! ;)
I believe that is incorrect. There is a fuse in the plug no? If so, it is current protected to maximum of the fuse, meaning it does follow European regulations and can be sold. Besides a shorted cable will draw more than 5A, but we never see it draw more so it is limiting the current. If it draws more and blowing the fuse then it would be illegal.
That PSU is perfectly acceptable to use as a means to detect faults without modification. Lets say i have a circuit that normally pulls 2amps at 12v with a suspected short. I would set the PSU to 12v and 2 Amps. If the circuit has a short it would drop the voltage close to 0 but still pull 2amps. This would still protect the circuit because the PCB is desgined around 2amps. If you mod the PSU to bypass the constant current feature, the said circuit would probably catch of fire! I believe he does not understand basic electrical theory. I would be worried sending my laptop to him to fix.
I have the same Power Supply and I can confirm that it has a Short Circuit Protection. Even though is showing the Amps is not actually out putting anything. It's showing there so you can limit the current.
I've tested with a load (lamp) and as soon as you short it the light goes off meaning the PS is cutting off.
Perhaps Sorin could do a video disabling the SCP on the PS. I'm desperately waiting for this so I can learn it.
hi sir I am just a beginner. I just want to ask if using a power supply without short protection for troubleshooting shorted parts on motherboard will get damage in the long run?
So what types of power supply should one get that is good to detect shorts? Thats the only reason I want to get one.
By the way it's fan is temperature controlled. Try to lower the current to 1 amp and you will notice it is switching ON and OFF
This kind of power supply is used to identify possible short circuits by heating components. Very useful indeed.
you can set the current to low if you want protection or higher if you want controlled heat to build up. A thermal camera is often used to spot the heated component.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
Fan speed controlled by temperature will be a great video. 👌👌☝️
I have the same model and it does the same thing. Thought it was normal and it was 😊. The fan works when using Higher voltages, but with a well cooled room your not gonna be having any problems
How long have you had it, and how much did you pay for it?
@@NeuronalAxon I've had it for a year now and i paid a round 60$
@@11111111Moe111111111 - Sounds good. Thanks. Do you use it a lot?
@@NeuronalAxon I don't use it alot but at the same time I don't abuse it. 30v-5A D ZHAOXIN is the model RXN-305D
@@11111111Moe111111111 - Cheers - I'll check it out.
Try turning the amps down while your shorting it, that's how I use mine to limit current.
Sorry for being stupid, but how do you mean?
@@NeuronalAxon By using the adjustment while 'under load conditions' to get a more accurate setting of current control. Sort of like when you get a voltage drop when using a switched mode power supply (electronic transformer) the output can be many more volts just taking a bare measurement than when you are actually powering something. Hope that makes sense.
@@Danechip - Gotcha, I think. Kind of like compensating for a non-linear response over the whole range?
@Arnold Rimmer Read it again Arnie. Brian was saying he shorts his PSU to set the current, not test for short. He has shorted it on purpose FOR a purpose, not to diagnose whether a fault exists via a short.
@Arnold Rimmer Its not about being used for testing for short, also in design you may not know the demand for current. In an ideal world a circuit would control this, but what about an oversight, lets say an LED without a resistor. That baby will suck as much current it can until it destroys itself. We could just put a fuse inline and rely on that but it's also not accurate. A bog standard 13A fuse will quite happily run for hours at 16A without blowing. So back to what has been said before, assuming the indicator is actually at your setting under short without having a 20% ir whatever tolerance, I would set my PSU the same way with a short. I would also check it inline with another meter to see how close it actually is, lets call it a homemade callibration.
This is neat. It is identical to the one I have. I took the handle off so I could put stuff on top of it.
please do a full cover video with all customizations which can apply
? For what? He did it already, search in his videos...
yes I would like to see a video of this too
One of the best technicians on youtube and never used a linear power supply! There's nothing wrong with that power supply. You are in CC mode
Hi Sorin, you are a great guy and you made me laugh out loud. I’m sure you know already to short the probes to set the amps 👍🏻
You should probably read the manual first... You can set the current limit with the current nobs when the leads are shorted. You can set the voltage when the leads are not shorted.
(10:00) - put the tweezers in and then lower the current by turning the current knob ANTICLOCKWISE.
The current draw should, I say should go down...
>
Instruction manual says it can be adjusted from 0 to 5 amps. Did you read the instructions 🤔 part 4.2
Thanks very much for your time and good work keep it up your REWARD is in heaven !!!
#. I want to know;
What type of phone heater and air compressor are you using ?
I got the same. It's a good tool!
I use it with your good advises !
CC means Constant Current.... that is the current stays constant even in a short..... that is even if you had a superconductor at 0-ohm, a 5A limit is 5A.... it will apply a voltage across the conductor for 5A flow (in the case of 0-ohm the voltage will be lost across the power supply internals).
The voltage is supposed to drop as per V=IxR where I and R is fixed and thus the V follows.
This CC mode is how I manually recharge Lithium batteries.... set max voltage, set safe charge current.... hook up batteries, charge.
When nearing 4.2v per cell it is advisable to supervise the batteries...
For circuit diagnosis, set to about 800mV (1v should be OK) as sensitive circuits may be down stream of the circuits.... this can help locate the short by literally heating up the faulty component (unless said component behaves like a wire.... then educated guessing applies).
CC mode is super useful.... having a current limit cutout means you could've applied, maybe up to 30V and 5A for even a fraction of a second.
so this is the best powersupply to find short circuits because you have nothing to modify right? it will work just out of the box and we can follow your lessons with it right?
Hi sorin, I'm a very good fan of your Chanel and I will like to specially thank you for your good work and for all the effort you put in uploading all those educative videos.
I must confess, your videos has helped me alot in my repair business. As a matter of fact, I have more than 80% of your videos downloaded on my device.
But dear Sorin, I will love it if you can do a video on How to disable SHORT Protection on a power supply.
I recently got a new power supply ( 1502DD series) but it's seriously limiting my work becos I can't use it to find short on any shorted iPhone.
Thank you so much for your contribution and help towards my successful electronic repair business.
....................Your very good fan from NIGERIA.
Just jump the 100w resistor.
@@andrewverran3498is it only one that is present in the power supply? Can you better description on how to do this?
Good video. Thanks for sharing with us.
This power supply it is dangerous. 0V 5A its shorts circuit eventually it will burn.
Don't forget to check every day if its not on short or off before leaving.
Like you said, left the producer with defect :D
If this psu had an overload protection we couldn' t find a short.That is because the psu would set the current to zero
you mean if it had short circuit protection....which it doesnt... you could still find your short as it would unexpectedly switch to 0 amps...when you expect it to be taking amps..that identifies your short on a short circuit protected power supply.... the psu has overload protection...you can restrict the current with the nobs...
i have a WEP 305D, it does the same thing, and it's react like your modified powersupply. I'am happy with it for finding shorted component :D
I really love your videos Sir. you are really doing a great job. please, i would love you to do a video on how to use a Power supply in PC and Smart phone repairs,. and also, Understanding a multi-metre for beginners. I've watched many video's concerning this on RUclips, but none of this video's has made me understand how to use these equipment's.
Thank you
pretty sure the replacement will do the exact same thing it does nt have any over current protection just constant current
I have pretty much the EXACT same cheap chinese power supply. Its constant voltage UNTIL you hit the current limit that you set. The fan noise of mine is near silent until you short it. Once shorted, it cranks up the fan speed (which it would need to do to get rid of that heat)
One thing I wish it could do would be to show what the current limit is set at (without having to short it first)
To everyone confusing 'short circuit protection' with 'current/voltage control/limiting'...
The issue is that Sorin thinks the PSU should cut-out in the event of a short circuit but when he shorts the wires the unit keeps supplying power. He fully understands what current/voltage limiting is, that is not the issue here.
I am no expert but I think that the short circuit protection he is looking for is internal - ie the unit will cut-out in the event of an internal short but not due to a low-resistance-load short of the type Sorin created?
Yeah it will limit the voltage doesn't matter if he is pushing 5A the voltage isn't rising or going anywhere. He was just confused i think. >D
I agree. I think the short circuit protection that is advertised is if there is a internal fault.
Finally found the good comment.
You're the only second commenter who understands what's going on. So many people are so quick to say sorin is confused
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
I have the same but different company name! What I first did is put it low cost temperature sensor for a fan, because it is too loud. When you make a short it get hot really fast!
It's working. It's supplying 5A because you turned the current up to 5A. What did you expect it to do differently?
It should stop the current flow by it self as soon as it detect a short in the output that's how it should work with protection
If it's heavy, It's good unless they have placed a piece of iron inside to make it feel premium.
thank you Mr.
maybe if he presses the STOP/OUT BUTTON..then it switches into short circuit protection mode rahter than constant current or constand voltage mode.....otherwise it broken as the voltage of say 10 volts is reading 0.4 ...which implies that the potential difference between live and ground is zero due to shorting...but the current is still flowing....and the manual said that it has short circuit protection...which it hasnt ..it has max current limiting...but no short circuit protection.
had it got short circuit protection..then when the voltage drops from 10 volts to 0.4 volts implying a short circuit as potential difference between live and ground is now close to zero....the current should stop flowing ....this is short circuit protection....
on his unit current keeps flowing...and if he left it for an hour ...would mean fire....not only that woudl melt plastic leads....would burn out chips in the device....
would have to buy new device...and also new house that burn down.
this is not short circuit protection.
your child messes with electronics.....leaves leads touching and goes out to play...next thing house burn down....
no short circuit protection...
you must be bloody stupid to think it is short circuit protection...also on delicate logic circuit ..you can blow chips with just little touch accidentally if short not protected.
@Arnold Rimmer mostly correct ha ha..i just educated you as to what current limiting protection is and short circuit protection..and you answer like you taught me something...ha ha you funny guy.
yes please do it.. temperature control fan.
I have a power supply that works like this one, the wanptek nps306w, but I can't figure out if I can use it to inject voltage. Will it heat the shorted component?
Those protection maybe design for internal circuit, not for the output of the power supply. And that power supply require you to shorted the prob in order to set current limit.
i have same type of powersupply for the past two years, and it operates the same way as this one...
Let me explain: CC constant current, CV constant voltage, OVP over voltage protection, OCP over current protection. That PSU only has CV and CC. If you want one with OCP and OVP you need to pay a little more :)
OMG !😊
Sorin, what kind of power supply have you used in this video, what model more exactly? 🤔 Thanks
so its already jailbroken 😔 I have this type of power supply too, if you short it you can adjust the current, but as i understand if you put a device that draw 1amp like a fan even if you set it to 5amps it will only draw 1amp, so its a protected?i thought removing that limit force supply to send full 5amp, thanks again for the video 👍👍👍
You can't 'force' current into something though. Now a hard short will draw whatever you've got until something pops, but other things... not so much.
I think Sorin is just getting us with an early April Fools episode ;D
that's normal, connect +ve to -ve, set your current limiter using the current knob. then disconnect, now on you can't exceed the current you set, when exceeded red led will be ON.
Love the tweezer in terminals. 😍
I’m surprised that you are surprised... This is the model 305, meaning, I guess, 30v 5A max. So what are you expecting from a short? 5A, 0volts of course...
Its called a class 2 power supply here in Canada
I thought you would want this feature for your brute force method!? I have this exact same one and operates the same. Did you have to modify your other power supply to behave the same way or something?
Sorin is speaking about a very special power supply having a “FOLDBACK CURENT LIMITER”. Very rare (and expensive) for a lab power supply.
It's just like when a math-professor makes a simple error like 2+2=5 :D Every student can see it, so everybody is laughing and pointing. Forgive us Sorin, we still respect you highly for your great videos, experience and amazing knowledge.
Hi Sorin, I have a question.
Is it good to lubricate the hinge of a Laptop?
I have question, why necessarily having a big transformer is a good news? what's wrong with the switching power supply as a power source?
Hello Sorin I have exacly same power supply. But soz Im begginer Im scared to use it at all. Can you show how to make short circuit protection for this one?
5 Amps but almost 0 Volts. You have no sparks when you touch the two probes. The user manual indicate to short the PSU for tune the amps, and after you need to unshort to tune the voltage. I think this is a feature. Try to have 2A 2V like in your videos on a faultly MB, per example. It's impossible. The voltage will bringing down to 0.0x
There's two kind of current limiting constant current and foldback current limiting, lab power supply usualy use c-c not the fold back
In all your troubleshooting video with a short circuit issue. You always inject voltage in the circuit and find the component that gets hot. You always show us the current goes high while the voltage went down. Now you did the same, you short the output. Current goes high while the voltage went down, and you now you will say power supply is faulty? Whats the difference?
He says the power supply is expected to cutoff or regulate the current, which it does. The current is limited to 5 amps.
0:32 Sorin's shirt changing colour
I have the exact model for 3 years and sometimes it runs for 3 4 hours giving around 2 amps constantly and still works like a dream, I put a resistor on the fan and it's much quieter and barely warm after a few hours.
It is short circuit protected. It's limiting the current to what you set it AT and it will not exceed that. It is doing exactly what the specifications say it should do and exactly what it's supposed to do. What were you expecting it to do? It does not have "over current protection" but you would not expect that on a budget power supply. You know, sometimes it's up to the user to do the sensible thing. If you attach the power supply to a circuit that you expect to draw 1A and you set the supply to 5A you are an i???t. Seriously, what do you expect it to do?
Sorin, you turned the current limit up from 4 amps to 5. And complained. Not a single attempt at turning it the other way. Can you hear the viewers screaming at you?
I think he is hiding and kicking himself. Perhaps in hindsight he would have watched his own video back before posting it. I am sure he would have spotted it. I was questioning myself while watching this if I had started forgetting shit from the past but still screaming at the TV to look at the BIG red numbers on the display.
I have seen a couple of short circuit protection videos, isnt a matter of opening the piwer supply and seeing if the large eg 100watt protection resistor has been jumpered? Might be a lesser value for lower max current supplies.
What is the problem? You have set the max Amp to 5 amp. Adjust it.
Mine cuts out when the unit itself can't handle the MAX current BUT this current can only be reached if potentiometer is changed inside the machine to above the set value this unit comes with, therefore allowing the unit to go above 5 amps. My unit can handle 6 amps therefore mine is within the range
Hi Sorin,you should put your PayPal on your page so people can make one off payments to help support the channel.
Hello Sorin, can you do a video on how to disable short circuit protection in power supply unit or is there a video on that already?
Sorin, pe cand un tutorial despre cum sa facem un circuit de protectie electronica pt. scurt-circuit ?
Multumesc anticipat!
It's not faulty IMO....it's in Constant-Current at that point, so it brings the voltage down to maintain the current you set, since it can't tell the difference between the wires being shorted and, say, a "true" 5A load.
Voltage going down,is that protection?
Current is only limitation and when you increase current voltage drops and protect....
Yes! he is misunderstanding how it works. The only way to control the Power going to a circuit, is to modify the voltage, or the current. P (power) = I (current in A) x V ( Voltage in volts). The current is a function of the resistance in a circuit and the voltage applied to it. ( I = V / R ) , so if you want to limit the current, with a set resistance, you HAVE to lower the voltage. You could add resistance into the circuit, but it's the same effect, as you have just created a resistor divider which also lowers the voltage, by dividing it between two resistances.
This PSU lets you set the current limit, and it will supply the set Voltage, till you reach the current limit, then it will at that point switch from constant voltage mode, to constant current mode, and reduce the voltage to stop the current from changing. You can only fix one part of the equation. If you want a constant current, and the resistance is changing, the only thing left to change is the voltage, to keep the current constant. As soon as you fix the voltage, and the resistance changes, the current HAS to change.
RTFM maybe. Button in the middle labeled "Stop"/"Out" could be current limit mode or constant current mode? 1:17 - 1:21 then 2:18 - 2:30 = Mmmmmmm
Yes! Was waiting for this one.
Just a simple mistake guys go easy. Nothing can refute the fact the guy knows his craft and trusts his instincts... maybe too much and it's in such cases that one makes such errors. Thanks for the video sir I know you later on figured it out.
It turns out you were wrong and Sorin was right.
@@Ghost572 you missed the point and purpose of comment
@@TechbayElectronicsRepair You said he made an error three times in you message, when he didn't. I don't get what point I missed.
You are wrong, Sorin is the supreme electronics god.
@@Ghost572 okay boss there's no point in my comment. Sorin didn't make any mistake. He is the god of electronics hallelujah amen and goodbye
Merhaba. Hello from Turkey.
If it's heavy it's good...
I have the same unit and it is doing the same thing.
Sorry for you Sorin, This time, you're wrong!
The power supply is working fine! It works just the one on my bench! The power supply is regulating the preset current (5A) adjusting the voltage... You can regulate how much current you need, rotating the current knobs on the left, in the front panel! Maybe the one you have on your benchtop works differently, but all the power supplies I ever had (also HP, and other hi-valued supplies works like that...
So, I think your power supply works fine (with no "click" ok..) but I'm used repair with a power supply just like the one you are showing, setting the shor circuit current BEFORE i actually apply it to the circuit...
Hello Mario. What kind of values do you use for the current when sorted (set up mode), and after for the voltage when unshorted. I means, the values of A and V to find a short on a motherboard. Thanks for your reply
@@poloemilien4858 If you mean the Voltage/current injection procedure Sorin does, it is very simple:
If you are checking the 19V Power rail, you set 19V on the power supply. If the 5V, the 5V, etc.
For the current, you short-circuit the power supply terminals and start with few mA. Then you connect the ground terminal first and then the Positive terminal.
Then if there's a short, you can see the current you just set-up on the Power supply display.
After you can try to raise the current, acting on the CURRENT KNOBS very slowly, trying to find the component who will become HOT (using some Petrol or Isopropylic Alchool).
*Follow the procedure that Sorin uses in most of his videos*, and *BE CAREFUL* not to touch anything else, or you will destroy other components non related the fault you're investigating.
Hope this will be clear enough.
Ciao.
Mario
PS: Lavolta.
EXACTLY SAME ONE.
>
Where do I get the proper leads to hook up to Power supply?
WHERE YOU BUY FROM?
Open the case!
In same way with this psu, when i want to put 1v on laptop motherboard, often i can't control current, can you tell me if it's normal? feel it sometimes useless. Thanks
Am use to the fan going up when ever am working with short
Sorin welcome to constant current mode which is a protection since you can't go over the PSU max current or your own set current :) electronics are wonderful aren't they ? …
for what you do , injecting external current into shorted components, using either smps or linear PSU is the same.
Linear PSU are used in circuits where low noise is required, like for example , quality audio amps.
It’s a nice power supply
Just get Rigol DP832. You wont regret it.
Cook Hotdogs with it...lol
I don't understand the problem here. Constant-current limit seems to be working just fine, so...uh, it's working fine.
Don't understand, it seems to work like yours. If the limit is 5A and the load takes it it push 5A...
Of course. There is no problem on this one. Sorin did not set the current limit potentiometer.
Sorin definitely knows that. I think he's just getting old
@@fixlab3047 Not exactly, he want the other feature for psu what is cut the line at over current cases. See my other post.
According to eBay rules, you can return the PSU to the seller, provided you have a good reason.
There is no fault.
They are noisy I've got the same psu with a different brand , and I'm waiting for the video on fan regulation or the fan connection to the 5v
You could get a fancier fan that fits the hopefully standard-sized fixings on the PSU, and/or just put a resistor inline with the existing fan cable to slow it down.
@@NeuronalAxon I do not think it is a good idea. If u reduced the fan speed, u can burn ur psu. u may use a bigger and better profiled fan, not just a slower one - I think.
@Arnold Rimmer But I do not want to pay extra attention just for a fan speed, I prefer if the unit do it automatically. U can do, as u want.
@Arnold Rimmer Yes, u are right. Mine one do it well in 0-100% auto, I just told to Neuron, if he want to using a fix resistor is not a good idea to slowing down the fan, because on max power, the PSU will need max air flow. The less could burn it.
Power supply is good, firstly you select the voltage value, then you have to short the leads so you can then select the current value and that's it.
CC mode, all ok, what is the problem?
my power supply does same as yours ,same make and model