This is not something I will do immediately, as I am not in fear of the screen dying in the event of full capacitor failure (the overall effect of the comments I’ve received on this post have put me somewhat at ease as regards my stance on dealing with capacitors), but it’s now on the list of things I will eventually need to take care of. Since I wrote this post, I have noticed what seems to be evidence of capacitors beginning to fail in my Sony PVM RGB display. The capacitor plague is due to faulty electrolytes of this type. Part 4: summary of failure modes (re-posted because formatting died in the first one), -Electrolytic capacitors And don’t use a “re-cap” project as your first soldering practice. (2020 Edition) - Byte Cellar, Have a Helping of 8-bit Holiday Cheer! most of the capacitor failure I’ve experienced have been in early to mid 2000s machines, they tend to have very obvious bulging when they fail. A capacitor is a passive two-terminal electronic component that stores electrical energy in an electric field. As far as failure modes, these capacitors are generally fairly stable. There are generally two types, however. Wax paper capacitors in tube-era equipment are well known points of failure. Lelon has always been a terrible brand - one of the primary brands associated with the so-called "capacitor plague". Looks like the capacitor plague is still claiming victims after all these years. This is basically what I have heard in the forums over at amiga.org, amigaworld.net — people getting 600/1200s on eBay and needing to do cap work, and people offering recap services for the 600/1200s specifically, as opposed to billing the service as something for all Amigas (not that there aren’t occasions where an A500/2000 will have caps failures). According to Wikipedia, the name of this phenomenon is “Capacitor Plague“. stack hosing cross bus traffic, so not a huge loss. If I’m repairing or restoring a machine for sale, I’m likely to replace some caps “preemptively” because I assume the owner is unlikely to ever check for leakage. https://www.youtube.com/watch?v=eFSNgDQS5JE. Some re-cap situations are a balancing act between possible damage from failed caps vs. possible damage from the replacement job. Adrian from Adrian’s Digital Basement here — and I now have upwards of 70 vintage systems, many of which needed lots of board repair when I got them. If I come across one that is leaking and/or bulged, sure I’ll change that one… but for me on all these systems, it just hasn’t happened yet. They also do not have very accurate capacitance (a typical tolerance range for electrolytics is +80/-20%, though you can find +/-20%). Just because later cheaply made electrolytics are a plague to electronics, it doesn’t mean the stuff from the 70s and 80s are problematic and unreliable. He echoes what I have heard in forums re: these Amiga models. Gloria. I had experience of more than 30 years in repairing electronics. Under the circumstances that’s not bad (especially compared with the “disasters” that I see in modern SMPSs). Leaking caps need to get replaced soon, and the board needs to be cleaned to prevent further damage. –generally fairly robust in terms of aging In my work in industrial electronics I mostly come across A-brand caps, no doubt. Evercon. Fujicon. Even leaking capacitors can still have the right capacity, so you might see problems when the first PCB traces are open due to being etched away by electrolyte – or even worst shorts by electrolyte, which can damage other parts like noise suppression inductors. Wiberg, E. and Holleman, A. F. (2001). I’ve described this adventure on my site (Everex-286 and MFM harddrive) [ Blake here, linking to his post (Romanian) and via Google Translate to English. ] Again, there are a wide variety of dielectrics used in film capacitors, ranging from simple paper, to various polymers such as polyethylene, polypropylene, and even teflon/PTFE for certain special applications. I have seen that as well, but didn’t think of it when writing the posts. Electrolytic capacitors are usually found in power supplies. When I look at a system, I will judge its age and the quality of the caps installed. A while ago, i recapped 2 CD32, 1 A600, 2 A1200s for exactly the same reason. Lately I’ve been tracking down troublesome capacitors in the vertical deflection circuit of a mid-80s 14″ CRT I own, visually they look ok and the symptoms appear to be a loose connection. These also had major input and firmware probs with the USB 1.2? However, many of the cheaper brands of caps, most notably those coming from east asian manufacturers, have historically had problems in this regard. There is an epidemic of failure in electrolytic capacitors from certain shady manufacturers. The physical form and construction of practical capacitors vary widely and many capacitor types are in common use. In my experience repairing machines and talking with those who repair them, there are some known replace-on-sight caps. Failed capacitor. These capacitors are encased in an epoxy potting material, and the thermal expansion coefficients of the epoxy is not matched well, apparently, to the other capacitor components. But we’re talking about vintage computers. Recently on EETimes.com, Max the Magnificent considered what was described as The Great Capacitor Plague of the Early 21st Century.This prompted several readers to comment reporting various levels of experience with recent capacitor problems. I would like to continue on as I have always done, using these systems as-is with the plan of replacing capacitors on a given system in the future, as they inevitably fail. Once that happens, the rest of the cap will quickly go, possibly shorting out a supply rail. I Sit at the Round Table (And Dance Whene’er I’m Able), Looking Back on 35 Years as an Amiga User, The Infinity Modules Player: Never Turn Off Your Amiga Again, Apple //c Scene From ’80s Bond Film “A View to a Kill” Perfectly Re-Created With Applesoft BASIC, The eMate 300 Out In Front for “BBS Week V”, Firing Up the Apple //c for “Not x86 Week”, Announcing “NMSspot” – My New “No Man’s Sky” Blog, A Quick “Heads Up” for My New BBSing Resource Page, The Amiga 1000 Sings Songs of the Season for Holiday Music Week VII, Have a Helping of 8-bit Holiday Cheer! Electrolytic capacitors used in linear power supplies (those operating in purely DC circuits, or in simple transformer+rectifier supplies) rarely fail in my experience, since they tend not to get very hot. More and more I’m seeing these responses come in the form of something like this: Ok, so your Amiga 500 powers on but goes to a full yellow screen just seconds after boot? I can’t say for sure that I have ever seen an example of a capacitor failure utterly destroying a system. Not sure why. CTC. –shorted caps may be found by deliberately supply excessive current and letting it burn On the other hand, I’ve seen plenty of failed capacitors in SMPS, and I’ve seen and heard about failures in CRTs, particularly the high frequency/high current deflection circuitry capacitors. But name brands like Bosch, Apple, Samsung, etc has quality processes in place and those practices just wouldn't wash. I had heard that the cap electrolyte recipe theft story was actually a cover for a major supplier screwup, so as not to damage their rep. Only probs i have had was with elcaps failing on 90’s vintage boards, even a Gigabyte and other major suppliers. There have been a number of reports in newsgroups and on-line services about leaky electrolytic capacitors on computer motherboards. As such, much of the discussion being had in the message bases is in the form of help / advice requests posted by people with ailing systems of yore and replies by those offering up helpful suggestions. Motherboard Capacitor Problem Blows Up - Faulty electrolytic capacitors could be a ticking time-bomb in your PC. capacitor plague) in electrolytic capacitors (typically Taiwanese low-ESR types used in switching power supplies): Arcon. Tantalums are also generally used where bulk capacitance is needed for power supply filtering, but they don’t get nearly as large as electrolytics, and they aren’t quite as dense. A notable capacitor, are the Rifa safety capacitors made from a paper dielectric. —capacitors have higher internal losses in this case generally, self heating can cause capacitors to fail They often leak electrolyte, which can cause extensive corrosion and dissolved traces. YMMV. I’ve ran 500s and 1200s (and the 600 is in many ways the same build as the 1200) for god knows how many years, and not once, ever, did I experience or hear about a cap problem on any of them or their PSUs. As already explained, the electrolyte leaks from these down beneath the part, slowly corroding the traces on the PCB underneath the capacitor while often remaining invisible to the naked eye. But what are A-brand caps? I have seen designs where two ceramic capacitors are placed in series, at right angles to eachother on a board, to reduce the likelihood of *both* ceramics cracking, and shorting out a power rail. My 34 year old A1000 and the A2000 run great without issue. Final thoughts. Oh and regarding linear power supplies: some old network switches with unregulated (trafo, bridge rectifier, capacitor) “power bricks” had this problem (cap going bad inside the power brick) but that might have been thermal issue, coupled with long (>5 years continuous) power on time. Outside of my Mac SE/30 and Mac IIci which had horrible visibly leaking surface mount electrolytic caps, I have never had to replace an electrolytic on any of the other systems. The "normal" lifespan of a non-solid electrolytic capacitor of consumer quality is roughly six years for a 2000-hour/85°C specification capacitor continuously operating at 40°C. Fuh Yin. They do have certain desirable characteristics, like lower ESR than electrolytics, which can be advantageous in certain applications. The manufactures specify a 2 year shelf life, but advised this could be extended by regularly charging the capacitors. GSC D-paston. —fail short with spectacular cloud of smoke After removal, you usually find the mess below the capacitor. Many have had significant damage requiring many hours of sometimes ugly repairs and reconstruction of circuit pads and traces that simply no longer exist. I’d just like to emphasize what I think is the main takeaway from this: I’ve rarely seen capacitors in linear PSUs and generally low stress environments fail. Over the years, there have been massive quantities of name-brand, high quality motherboards failing prematurely due to these faulty electrolytic capacitors used in their manufacturing process. The video section (located beside the IDE port) was just about working but wouldn’t have lasted much longer, and required all the components (not just the capacitors) to be removed and cleaned up or replaced, as the corrosive electrolyte had seeped underneath the flat parts and was eating many of the traces beneath them. If it’s an 80s system or earlier, I never proactively change the caps. But it’s a little bit more complicated. the infamous 68k Macs, I’ve had one Mac Classic with this exact same problem, and also a friend working in a another service shop told me he was replacing hundreds of small 1uF capacitors in camcorders in the late 1990s – early 2000s. Materials commonly used as dielectrics include glass, ceramic, plastic film, paper, mica, air, and oxide layers. So my advice to you would be to have the capacitors replaced in all of your machines that use SMT capacitors, but just carry on as you are with the through-hole machines. –known to fail short, I have never personally seen them, but it otherwise seems like a common issue other people have reported If your soldering skills (or tools) are basic or mediocre, I would not recommend re-working boards like these. Failed e-caps with well known brands may have had failures not related to defective electrolyte. I posted a high-score photo of my Amiga 2000, to which the PVM is attached, to r/Retrobattlestations and a reader with the same screen noticed a set of divergent RGB lines at the top of the display and told me how to adjust the display settings to remove them. We have one client using old “Fr.Hesser” AWD-1 powder filling machine built in 1970, working 24/7 since than. Elsevier. Re. Every capacitor has an intrinsic loss, and this is often expressed as an ESR. So conclusion is that today elcos for consumer and low end industrial products are deliberately not built to last. But even machines that show no symptoms can be on the brink – one Amiga 600 I recapped recently had a CF card installed as a hard drive containing lots of games, and was working just fine. VidHD and “Total Replay”: Two Great Tastes That Taste Great Together! After doing a bit of research I found that the problem was most likely the "capacitor plague" which affected millions of capacitors made about ten years ago and used by many companies in all sorts of devices from vacuum cleaners to computers, and the typical symptom is capacitors exploding well before their normal lifespan and well within their specified voltage. I used to earn a lot of pocket money fixing the bad cap in BBC model B power supplies (note to power supply designers, don’t exceed the voltage rating). But, I would like opinions as to just how risky this is. But last 20 years, consumer electronics, computers and even prof. electronics which I repair, is much, much worse – elcos are maybe 1/3 or more of the malfunctions according to my experience. Yeah - cheap capacitors are the bane of a lot of electronic items. The capacitor plague was a common problem in recent years, causing failures in all brands of electronics, including brands usually known for higher quality components. If you need recapping service, let me know. If you suspect there is a shorted tantalum cap on a board, and you’re not sure which one it is, a good way to narrow it down is to apply a controlled amount of current from a lab power supply in constant current mode, and find the hot component. Home de molts oficis, pobre segur - Jack of all trades, First character: Year of production, M = 2000, N = 2001, P = 2002, R = 2003, S = 2004, T = 2005, U = 2006, V = 2007, W = 2008, X = 2009, A = 2010, B = 2011, C = 2012, D = 2013, E = 2014, F = 2015, G = 2016, Second character: Month of production, 1 to 9 = Jan. to Sept., O = Oct., N = Nov., D = Dec, capacitance value decreases to below the rated value, relatively high and fluctuating leakage current, increased capacitance value, up to twice the rated value, which fluctuates after heating and cooling of the capacitor body, Bulging of the vent on top of the capacitor. Considering each capacitor is a few cents and soldering skills improve with practice… Really why are you arguing against that? —risk of damaging board I’ve always been somewhat apprehensive about electrolytics in older computers (1980-1990) but even 30 years later, capacitors in their SMPS measure good both in capacity and ESR (maybe 10-20% under nominal capacity but generaly not worse than that). It can be more than 10 years for a 1000-hour/105°C capacitor also working at 40°C. Where did you hear this? On the other hand, electrolytic capacitors used in switch-mode power supplies (SMPS) operate at very high frequencies and take considerable amounts of ripple current. Small note re: tantalum capacitors, there are a lot of surface-mount tantalum capacitors made by a number of different manufacturers. However, there is something else that might prove to be a problem for equipment from that era and that is smaller (in both size and capacity) decoupling capacitors with rubber seals. Apparently the proper term I should have used for this article should have been “Capacitor Plague” as pointed out by the Wiki. The rest seem to depend on how the machine has been stored/used and how it *will be* stored / used. The first are the bulk capacitance dielectrics, which are dielectrics optimized for capacitance density. When replacing, check the datasheets, in some areas, you need low ESR capacitors, if you don’t find the datasheets, my rule of thumb is that caps rated for 105°C should get a low ESR replacement. So my question is, should I use the same brand caps? It basically happened, when a company stole the chemical formula for the electrolyte; only that they missed a key ingredient. I’ll proactively change those or just remove them. Chhsi. But over … They leak, sometimes invisibly under the package, and eat the board traces. A conductor may be a foil, thin film, sintered bead of metal, or an electrolyte. They are only there to provide some EMI isolation to prevent noise from the equipment from making it back into the power grid, or vice versa. With tantalum capacitors I’ve had quite an interesting adventure last year, both the original and the replacement (replacement being around the same age if not older) failing short. I imagine the post is oriented towards electrolytic capacitors, but I’ll give a quick run down of the types you’re likely to see in consumer electronics. Interesting timing. –also generally robust in terms of aging Third, not only caps age, so why the focus on these? I spend a good deal of time these days on various telnet BBS that are (naturally) focused on vintage computing. This is exacerbated by the fact that surface mount electrolytics were a relatively young technology a the time, and Commodore used the cheapest they could get. holl_ands covered this point. –SMPS I’m into vintage computing myself but not in a very structured way. User #249219 171 posts. Other times, the power supply will kick on as normal, and deliver significant power into the shorted tantalum capacitor. Canicon. Image appears for 1 or 2 seconds, then Blank screen (image visible with a lantern), almost anhydrous electrolytes based on organic solvents, such as. It’s much more common in my experience that most or all of the capacitors in my old gear are still doing their jobs. Ceramic capacitors are generally a disk-type in thru-hole versions, and a small rectangular device in surface mount types. This goes to the extreme that newbies are told off for turning their vintage computers on without replacing all caps beforehand. Even my PC PSU bought during the capacitor plague era and filled with the now dreaded Teapo caps still functions OK, and it has seen quite some hours of service. Sling Media-Wikipedia. DST. I'm good with electronics and soldering so Im going to try replacing them. However, as expected, if the capacitor is mistreated, they can suffer drift in capacitance, or even short circuiting if exposed to bad enough transients. Fujitsu (FPCAP) Fulltec. #todayInTheByteCellar I wrote a blog post about an Apple IIgs game, Tunnels of Armageddon. Firstly, the vast majority of people have no idea that capacitors leak, so even a little exaggeration is justified to promote awareness. He notes that it’s a temporary solution, as the capacitors need to be replaced to affect a “permanent” fix. In this case, the results are much more spectacular, with the tantalum capacitor often literally catching on fire and blowing up. I’d suggest you test the power supply with a voltage meter, re-seat the socketed chips on the motherboard, and, of course, replace all the capacitors. Two classes that come to mind immediately are: Capacitor failure is real. Source: Wikipedia. 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