Am I in the right place?  Power supply capacitor replacement? - Page 1
Forum section: electronics / beginners

author: mynameissteve
author_rank: Newbie
timestamp: December 30, 2017, 02:57:43 am
content: Though this is technically a repair, I am also a first timer on this site. I'm pretty sure this is the right forum for these types of questions? I stayed here in the beginner section because, well, it just seemed right. The work I'm looking at seems pretty basic.Anyway, I have a Crossover monitor that came here (probably) straight from Korea. Crossover is the brand name. I believe the model number is "30Q5Pro". It's a pretty impressive monitor in terms of size and display resolution and I've had it for a few years now. I'm sure the 4K monitors they make now can probably compete at the price point, but at the time, 4k was relatively new, and this was a screaming price for 1600, instead of 1080. Well, the other day an odd smell started aromating, (I made that word up) around the computer area and the big monitor stopped working. It would just flash on and off.So I unplugged it, thinking it maybe got too hot. I tried again a day later, a handful of times, and it wouldn't work! Still smelled funny, I didn't connect the smell with electronics, because it didn't smell like burning! I could hear something clicking so I bent in thinking it was going to be one of my two graphics cards, but no, it was the monitor power supply!I unplugged it, pulled it apart, and noticed liquid in the power supply case. And then I thought, huh, maybe it smells like burned coffee? But no, my wife and I don't drink coffee and no one else sits at this computer. So then, as I'm sure some of you readers have probably guessed by now, I took a closer look at the capacitors based on things I remember hearing about tvs and monitors throughout my life and noticed one of the large capacitors was bulging at the end and it had a hole in it!So the question is I guess, Is it worth it to replace this capacitor instead of trying to buy a new power supply? I looked at the website for the PS manufacturer. (loadus.co.kr) and can't figure out much of anything. (I can't read Korean!) And I also didn't get much from the monitor manufacturer website.I have always enjoyed fixing things, and soldering, isn't totally new to me, though I have never worked with capacitors and don't really know how to properly verify rather it has a charge, and rather or not I'm going to have it discharge on me. I also read on an instructable that people recommend replacing all of the capacitors instead of just the dud because they tend to go bad, and may even be a slightly smaller spec than they should be to encourage failure, to get people to buy new monitors and so on.Any guidance and thoughts are appreciated? I have desoldered stuff off of a pcb before, and I have soldered (successfully) what I believe is called a "shunt" to make connections across a pcb where the circuit appears broken. But like I said nothing pertaining specifically to capacitors. I do own a multimeter, and I kind of know how to use it. (I can check for continuity, and volts like on a car battery) One capacitor, or all of them? Try to buy a new one, or repair? Is there anything else I should look at? Thanks!Edit: I just popped onto "digikey" and noticed at least 10+ different types of capacitors? So, another question, does it matter which kind as long as it's the same specs? Also, I've included a picture of the power supply with the case in half. It's the larger one, laying down horzontally in the middle. I tried to post a couple more photos, but had size limitations, so that's it for now. And, this is the instructable I referenced earlier.http://www.instructables.com/id/Fix-a-Malfunctioning-LCD-Power-Supply/Thanks again!

author: mynameissteve
author_rank: Newbie
timestamp: December 30, 2017, 03:48:25 am
content: I wanted to add these two photos. And maybe add that while I'm at it, if I could get rid of the Korea to US adapter on the end of the cord that would be nice. As soon as I took the picture, I was pretty sure that I could just use practically any other cord between the wall and power supply? It looks like a generic cable like all the other PS cords I've seen. Can I just swap it out? Is that safe?

author: kalel
author_rank: Frequent Contributor
timestamp: December 30, 2017, 04:18:26 am
content: [Disclaimer: Newcomer advice, limited knowledge]Welcome to the forum!Regarding the adapter, I'm not sure if the input voltage of the power supply, AC 190-240V is suitable? Unless you have voltage in that range over there. If the input voltage is unsuitable, that can cause issues.I just saw the sticker on the right, saying 110 is acceptable.Regarding replacing the adapter, you could buy another adapter with 24V 7A output, it doesn't necessarily need to be from the same manufacturer.Obviously, it does need to have the same connector, however. I'm not sure what that one is called or how common it is.You can definitely replace the capacitor, but I would wonder first what caused it to blow in such a way? If something else is shorted or improper, a new one could blow as well. Regarding the specifications, I would go with the same specifications written on the capacitor itself (take a look at V, uF, as well as temperature rating). As for the type, it seems to be electrolytic and it's best to use the same type.

author: llkiwi2006
author_rank: Regular Contributor
timestamp: December 30, 2017, 05:18:03 am
content: If you are buying a new capacitor, get one from a top quality brand. Also make sure to get a 105 degree rated one with the correct voltage rating (looks like the cap is the mains input filter cap, so 400V). Try get one with the same capacitance, but bigger is alright, just make sure the physical size is still the same so it will fit. Also take note of the polarity before you take the old cap off, the pcb might not have it labeled.Have a look here for capacitor brands:http://www.tomshardware.com/reviews/power-supplies-101,4193-5.html

author: llkiwi2006
author_rank: Regular Contributor
timestamp: December 30, 2017, 05:28:04 am
content: Quote from: kalel on December 30, 2017, 04:18:26 amLooks like it's the mains filter cap, so it probably just "died of natural causes". In my experience these power supplies get quite hot (they are in a sealed plastic box without cooling after all), and high temperatures destroy electrolytic all the time.Also, this power supply seems quite undersized, I would have expected a 168W one to be bigger. I wonder how hot this thing get while running?

author: mynameissteve
author_rank: Newbie
timestamp: January 01, 2018, 12:59:21 am
content: Thank you both for your responses! I have since ordered a replacement capacitor off of digikey. I checked the blown capacitor against the TomsHardware list, and found it in the "fourth-tier" list, "Lelon." In hindsight, I guess I'm surprised this fourth tier money saving capacitor lasted nearly six years.I can't say with certainty any specific temperature it reaches, but I will say it definitely gets warm. Not so warm I don't want to touch it, but warm enough that I've thought, "that can't actually be okay..."I made sure to order a replacement with the same ratings, and an equal or smaller form factor (same lead spacing). Though I do almost always opt to fix things instead of buy new; I can't help but wonder if it would be more practical and longer lasting to just buy one of these.https://www.amazon.com/VCZHS-Universal-Regulated-Switching-Computer/dp/B019OP6N8Y/ref=pd_cp_421_1?_encoding=UTF8&pd_rd_i=B019OOTL7A&pd_rd_r=QAWZPP5PZV0V31NPX4VF&pd_rd_w=9zs5h&pd_rd_wg=gySkY&refRID=QAWZPP5PZV0V31NPX4VF&th=1The attached photo is of the cord that goes from the power supply to the monitor. Would I be better off buying one of those 20ish dollar power supplies off of amazon, and cutting this cord out and putting it on the power supply? Is it that simple to get one of those power supplies with the cord I need, or is it more complicated than I realize?I also found this blog, where someone else also worked on their monitor (same model) and replaced their power supply, but they don't talk about the details of how they did the power supply part. Well, they kind of do, they actually changed the power adapter on the board itself first, because their monitor didn't come with the original power supply. I feel fairly confident from looking at the pictures of the power supplies on amazon, that I wouldn't need to do that, and that it looks like I can attach whatever I want as an output cord on the brass screw mount things. Once again, is it not that simple?http://nand-hate.com/2015/11/crossover-30q5-pro-black-30-2560-x-1600-korean-ips-monitor-repair-notes/Thanks again. In the meantime, I'll be waiting for my capacitor.

author: Gregg
author_rank: Super Contributor
timestamp: January 01, 2018, 06:31:52 am
content: Quote from: mynameissteve on January 01, 2018, 12:59:21 amBe aware that some of the cheap SMPS like the one linked may not be able to supply the full rated power into one circuit. Sometimes there are multiple outputs of the same voltage that are not balanced and cannot be reliably paralleled. Personally I would just replace the capacitor and hope for the best. If you have the capability to replace the capacitor, you probably are clever enough to give it some better cooling.

author: DC1MC
author_rank: Super Contributor
timestamp: January 01, 2018, 01:15:39 pm
content: Also make sure that you wash the whole power supply printed circuit board and surrounding area VERY CAREFUL, first with deionized water then with isopropanol, the liquid crap that pour out of a dead elco is MORALLY CORROSIVE for electronics, even if just some small residues are remaining, they will still cause bad corrosion in time.