Wanptek Bench Lab Power Supply damaged Output shorted repair fix NPS605W
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- Опубликовано: 23 июл 2024
- Hello everyone!
This is what happens when you try to connect a battery to a bench power supply using the wrong polarity... There isn't much protection in these anyway...
It is an easy fix as long as you have the diode...
Part number is MURF1660CT
#repair #diy #powersupply 
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Hello, I have a different problem. The resistance across the terminals is 2kohm. THe problem I have is that the power supply trips the consumer unit as soon as I switch it on. Do you know what the problem might be?
If it trips the fuse then it is a problem of the primary side (possibly shorted mosfet/transistor), but if it trips the RCD then something is touching the case inside? check continuity from live and neutral to ground (yellow/green wire) it should be in Mohms...
@@varnasfix Thanks Mr Varnasfix! I've just tested it again and a ceramic disc capacitor exploded on the primary side. What the?!?
@@AntonyCartwright That can be a filtering capacitor that shorted out, but it can also be a MOV, a metal oxide varistor which is surge protection on the input and they can also short out if they been hit by a big surge and short out, they are often blue and can be marked eg: S10K275 and looks a lot like a disk capacitor. they are typically placed after the fuse between the neutral and live wire
@@Pulverrostmannen I had a supply that had that blue one short out. in the middle of a storm the lights in house flickered and the power supply just went BOOM. then after that even with a new fuse it just went boom the second ya plugged it in. opened it up and seen the blue disk split open with black marks everywhere. i just cut it off and now supply works perfectly without it.
Edit... well it did work for about 2 years anyway. started to do the same fuse blowing thing again and this time was the 2 main input switching mosfets have gone short, Now just waiting on parts to arrive from overseas. fun fact tho, even with the main mosfets removed you can now power up unit and screen works, usb and rs485 coms all work just get no power output. can see the 24Khz switch signals to the mosfet base is working good and not overlapping on my oscilloscope so hopefully will all be good when parts arrive.
@@matthewvincent9504 yeah it sounds like you had a good jolt in your system there. Your FETs probably took a hit at the same time but not enough to kill then instantly.
The Mov is good protection but not perfect and it can only camp so much especially if hit by large currents that cracks it.
The display in the supply likely has a separate supply for that function and the output it’s own.
Good luck with your repair
Good job.
so i got the nps306w and it freakin died or well went into coma after i connected to a chinese hv spark module in a setup, no reverse or anything, just powering it and operating within input voltage rating of the hv module
it ran fine with the module itself but for whatever reason when i built a mechanical contraption to put this module connected to sharp electrode (see ionic thrusters) for experiment, it almost seemed like everything around is impacted by emp, even the computers were flickering, im not even sure the emp by this small thing can affect so many things and at quite a bit of distance, normally u d see this thing not even reaching 10cm in an emp device
seems everything was flickering to the discharge pulse of this module, even the power supply was affected a bit, it can be seen from the displays, well it ran fine until everything just went 0v 0a 0w, and the fan came on, which i only ever manage to get it spinning once under normal operation. before the disaster, it was outputting 10 to 20w maximum
basically everything stays 0 and knobs change nothing, fan always spinning as soon as powers on, measured the output, seems fine to me, rising resistance probably the output capacitor, so it s not shorted
perhaps i should have added a capacitor in parallel to the load and mybe even a diode? idk how the heck powering something at 4 to 5v managed to destroy everything, unless the hv somehow went back in the power supply, which idk how? like the electrons flew from electrodes to input terminals?
if u wonder why i didnt shut it down, i figured the computer can handle a bit of emp, but i sure am glad the computer didnt break had the hv module been actually affecting the mains, corsair really saved the day
anyways, i have some suspicions, maybe the emp really is that big, wat could that have damaged? or mybe hv went back to power supply, even worse, seeing as everything even the computer was flickering, could hv have went past the transformer and reversed itself into the mains power? if the emp wasnt the issue, mybe powering the module caused something to happen on the mains, so the damage could have come from this mains oscillation/surge or something? like the varistor could be broken, but a broken varistor would have gone up in flames by now
opening the power supply up, i see nothing wrong, i mean, it was a silent coma, nothing went pop. as far as i can tell, there isnt even a fuse in there anywhere, at least not in the shape that i know of
im lost, dont want to just change random stuff, wat do u reckon is broken? need ur help my man, big thanks
HV spark modules are notorious with back EMF (to the power source) but also any cable can peak up the high voltage output part hence all the trouble you saw on all the other devices... It was lucky that the computer was not damaged...
The fuse should be on the IEC power connector, it is integrated there...
Now as long as your problem goes the primary side of the power supply is working (if the screen lights) so it there is a very small chance the problem is there... Also the output diodes may fail open as well and may cause the problem... You have to desolder it and test it....
Hope that helps!
@@varnasfix thanks for the help man, so u sayin that the problem is likely on the secondary low voltage side yeah?
anyway, the conclusion is that im just going to scrap it, im suspecting some ic or digital part probably got broken, suspecting the one that controls the pwm from mains, controlling the transformer regulation, it would make sense with the 0v output too
i think we can agree that there is no additional fuse on secondary side or anywhere, just straight from the mains input, so it couldnt be the fuse, and also couldnt be varistor?
i measured and desoldered the diode, the one in this video, output diode as u said, it works fine, heck, i even desoldered the transistors, as no switching=no power and the transistors are for switching, but the transistors seem fine too
it is unlikely that the smd stuff like capacitors are damaged is wat i would like to think, given the nature of this damage, i think the surge probably damaged something digital like the regulator ic, not likely to be the output stuff around the displays though
the spinning fan that has been hibernating forever is literally telling me the answer, except im no expert to be tracing where the fan leads to, something connected to that fan will definitely tell me whats wrong, but man i aint got time for that and i dont know where it is
but heres the question, why was it that when i just powered the hv module like bare bones, it worked fine most of the time at least, but not when i built the thing around it? i think it is just physics, that the emf is bigger since the gap is bigger. But the actual question is that, when i connected the same contraption to an atx diy power supply after the wanptek went coma, it worked without issue, no flicker or anything, how and why?
i deduce from this that, the flicker is actually the wanptek itself literally switching along with the hv discharge, like the whole power supply is on hiccups, turning off to the hv pulse on the output, the power supply keeps switching and pulling power is definitely causing the surge on the mains, not the hv going into the mains or something, but why? some protection? what sort of protection even does that? and wat sort of damage is caused by switching itself on and off?
i think we can actually conclude that even an old and cheap atx psu has more and better protection than this wanptek crap box, even the whole design and topology seemed minimum/basic, the contraption worked totally fine with a makeshift diy benchtop atx power supply, but not with a purposely made benchtop powersupply
im tempted to buy another of the same model since it is half the price new since i last bought it, but idk if i trust these chinese power supply anymore man, do u think these cheap chinese power supplies are just a bunch of crap boxes too? seems some people on the internet also thinks so and wouldnt trust any sensitive circuits on cheap power supplies and now im starting to think they have a point......
Yes still probably something is wrong wrong on the secondary side of the power supply... The transformer is switching hence the display works, so one low voltage line is working...
About the HV spark module don't forget that it is a coil and coils create huge spikes! You display shows RMS and average and updates few times per second at most... If we used an oscilloscope with current clamp you may find out that amperes spike to 20s and 30s (even more) and voltage may spike to 50V or 100V.... protection diodes and filter may have saved the supply....
We cannot really compare these supplies to ATX as ATX are mass produced and bench power supplies are not.... Plus 12V rails on modern ATX supplies can give more than 20A....
Now if these bench power supplies are any good.... The only question you have to ask yourself is can you buy ANY other bench power supply for the money?
@@urnoob5528