Choosing Capacitors to Recap Old Electronics

hello friends in this video today i'm going to offer some general advice on how you can select the appropriate replacement capacitors to get your vintage computers or old electronic devices up and running again i'd like to start out by just giving you a little reasoning behind this video recently one of the paypal contributors to this youtube channel had asked me how i go about selecting capacitors how do i choose among the different brands like nichikon and panasonic what are things like rohs how do i pick out the right capacitors the size the lead spacing and all of that what he asked me basically what are my uh techniques and the thinking that goes into it now full disclosure i do have an electrical engineering degree that doesn't mean i know everything and some of you who are just you know hobbyists or technicians may have a a lot more experience in a certain area than i do so i'm not trying to make myself out to be some kind of know-it-all but at the same time i do know the theory behind it and i do understand appropriate capacitor selection and some of the pitfalls and so that's what i'm going to try to convey to you in this video today i should also point out that if there is a specific video or help guide that is going to provide all of the details you really need to recap for example macintosh 128k analog board then obviously that video is going to be better than this one because this video is just offering you general advice and by the way i i would suggest that you go to my channel and click on the little magnifying glass and then you can search and you'll find all of my different videos on those topics i even have videos on recapping the 128k motherboard recapping floppy drives and and things like that which you normally don't find on other channels so because i provide not only details on how to recap but i also provide the mauser carts necessary that you just buy it and then watch the video to replace the capacitors that really is the easiest approach in the event i don't have a video there are places online that sell capacitor kits one of the companies i've never purchased from them and i don't have an affiliation with them but console 5 is one of the companies that i've read that many of you in the vintage mac and other vintage computing communities have used to recap your macs or commodore 64s or other vintage computing devices they don't have a kit for everything though so it is possible that ultimately you're going to have to choose your own capacitors one day and that's really what this video is all [Music] about the first step is to decide what capacitors need replacing there are a variety of capacitor types and you do not need to replace them all what you're going to keep your eyes on are the fluid-filled aluminum electrolytic capacitors that usually have a cylindrically shaped body and these capacitors come in three types the first type is surface mount also known as smd or smt capacitors these have tiny little legs that come out the sides and mount to the top or surface of the circuit board the second type are radial capacitors they have legs that come straight out the bottom and they go through two drill holes that go straight through your circuit board the third and final type are axial capacitors these are very similar to radials except that they are laid down on their sides the legs come out each side of the capacitor and they need to be bent down at a 90 degree angle and go straight through the two drill holes on the circuit board now you don't need to worry about most other capacitor types such as film capacitors or ceramic capacitors or tantalum capacitors these capacitors do not have a fluid electrolyte there are wet tantalums but probably you're not going to find them on your vintage boards so in those cases you really don't have to worry about them now if you were handed a board that was recapped with tantalum capacitors solid tantalum i mean then in that case you might need to replace some of them if they were inappropriately chosen and the reason why is because tantalum if inappropriately chosen can go up in flames there are a lot of people who are tantalum haters out there and i am not one of them neither is nasa yeah that's right nasa uses solid tantalums and the space program they're even used in pacemakers the military uses them so if they were as dangerous as some of the tantalum haters contend they would no longer be sold today the fact is they are safe when used appropriately and i will admit that the ones used in pacemakers in the medical field and the military in space they go through some very rigorous testing those are on a magnitude better than what you would find on mauser being sold to the commercial or industrial or consumer markets but nevertheless solid tantalum is solid tantalum and it can burn if given the right voltage conditions and really that's what triggers it most of the time is excessive voltage so i'll go in more into detail in that but basically if you see ceramic capacitors or tantalum capacitors or film capacitors on your board unless they're cracked or noticeably burned you really don't have to worry about replacing those types you're going to be focusing primarily on aluminum electrolytic capacitors there is one exception to that rule and those are the safety capacitors that you'll find usually in the power supply circuit for example on a macintosh 128k analog board there are three refa safety capacitors right near where the ac voltage comes in and those capacitors don't often fail and they don't leak out a fluid electrolyte that will eat away traces or anything like that so it's not absolutely necessary that you replace those type of safety capacitors however reefer boxes do have a plastic outer shell and if you see that that is cracked then in that case i would recommend you replace them if those fail those especially on the macintosh motherboard they usually will crack open explode not a big explosion but basically crack open and sometimes they'll ooze some black goo out but even if you replace or actually remove those capacitors on an analog board on a vintage macintosh usually it will still work and the reason why is because those capacitors are there to filter noise i found an excellent video on the subject if you want to learn more and i have that linked in the text description below but suffice it to say if you're already recapping the aluminum electrolytic capacitors then you can just easily add those other safety capacitors to your cart and in the case of the analog board i already have a video on that i have the mauser cart set up to include those capacitors but in terms of the general advice that i'm giving you now on a machine not covered in my videos yes you could give a secondary look at those safety capacitors because they are the first line of attack that's where the ac voltage comes in where the lightning strikes happen where all of the noise comes in and so they can go bad so that's something else to consider when you're replacing these [Music] capacitors now that you know what kind of capacitors you need to replace we need to talk about how to choose appropriate replacements basically there are four important criteria that you need to give due consideration to number one is capacitance this is often printed on a vinyl label around the capacitor itself next is voltage this is the maximum voltage specification of the capacitor very often also printed on that vinyl sheath that goes around the capacitor body next is the physical size of the capacitor itself in terms of its diameter and its height and lastly we have the lead spacing now capacitance and voltage again they are often printed on the label itself but if your label is damaged or you just don't have it on there then you're going to have to find some other way to figure out what the capacitance and voltage is one way is to desolder and remove the capacitor from the circuit so that you can measure that outside the circuit and determine what the capacitance is keep in mind though if your capacitor is very old and has leaked out a lot of fluid it very well could be that the capacitance is way off and so any measurement that you measure on that capacitor may not accurately tell you what that capacitor was originally so in that case it's often best to have a schematic and that's not always easy to find and sometimes it's absolutely impossible to find but there is one other technique you can use if you search for whatever that board is or whatever the device is or computer using google sometimes you can go into google images and you'll be able to find a high enough resolution photo of the actual board and maybe if normally that capacitance and voltage is printed on the actual components you might find the component in a photo that exists on the internet and you can just read it off of that but a schematic would be really the best thing to have in the event you're you're not able to see what that capacitance and voltage is on the capacitor itself now in terms of measuring capacitance i would highly recommend this de5000 meter you've probably seen me use this in some of my other recapping videos this is really the best handheld lcr meter you can find l standing for inductance c standing for capacitance and r standing for resistance really the accuracy of this is very comparable to benchtop meters costing costing hundreds of dollars now this maybe not is not something that's worth buying if you're only going to do one recapping job because this plus some of these removable accessories will set you back about 100 us dollars but if you're a geek then okay it's definitely worth it you're not going to be able to measure voltage okay i think most of you who are familiar with these tools can understand that this is for measuring capacitance or measuring the esr the resistivity of capacitors you cannot measure the voltage spec right because well how do you know what that is so even though you can measure the capacitance you still may not know the voltage and in that case um i wouldn't suggest that you guess based upon the physical size of the capacitors because the capacitors for that were used in electronics in the 1980s and early 1990s are different than those used today today modern fluid filled electrolytic capacitors not always but many times are smaller sometimes substantially smaller so you can't really base it on the size of the capacitor itself and again that's where a schematic would really come in handy or asking people in online forums to help you out there can be a benefit but sometimes you can guess based upon the voltages going into the board for example an se30 motherboard we know that it's taking 5 volts and 12 volts from the power supply so 12 volts is the upper end voltage that you're going to see and so that's why on the sc30 motherboard we see 47 microfarad 16 volt capacitors on there there's 10 of them and that way you know okay it's the voltage of these capacitors needs to be higher than that highest voltage that the motherboard sees but as an engineer i'm not really too hip on guessing i mean if if if that's all you can do then well that's all you can do but try your best to find out whatever technical information you can so that you can be sure of the exact capacitance and voltage before you pick out a replacement capacitor now in the four-step criterion for picking out replacement capacitors in addition to capacitance and voltage we talked about the diameter of the capacitor the height of the capacitor and the lead spacing and i would also strongly recommend that you purchase something like this mitsutoyo caliper set calipers are you've probably seen these before even if you have never used them or don't own them these are digital calipers so they have a lcd screen and just like shown on the picture here it lets you go down to 0.1 or actually .01 millimeters which is a very very tight tolerance you could easily measure the diameter of a 5.1 millimeter capacitor and you're going to need to do that because you want to measure the width or the diameter and also the height of the capacitor so that of the stock capacitor so that you know approximately the height and width of the replacement capacity you need in addition to that you also need to use your calipers which again are much easier to use than a standard ruler you need to use your calipers to measure around your capacitor so your capacitor might for example be this capacitor and it's sitting right next to a connector okay so if this capacitor is say 10 millimeters wide and it's sitting right next to a connector and the only replacement capacitor you can find is 12 millimeters wide you're going to have a problem because that wouldn't fit there so you need to measure and figure out what is the maximum area that you have around your capacitor both in height and in width and that will help you to better pick out the appropriate replacement because again you may not in many cases the modern replacement capacitors are going to be smaller than the original stock capacitors but not always the capacity you need may be out of stock for weeks or even months sometimes and so being able to know what the actual space you have available to you is extremely important so you can pick out the appropriate capacitor you never want to buy a capacitor just based on capacitance and voltage alone because it may not fit and the same goes for the lead spacing how far apart are the two leads because the drill holes in many cases if you have a through-hole type of of a capacitor you can measure the mountains of solder on the solder side of the board that's kind of a more of a guessing game than complete precision but it does work fairly well if you want to be more precise you can try to desolder the capacitor and measure from the middle of one drill hole to the middle of the next using your calipers and they have the ability to do just that that is a more accurate way of doing it but usually a rough estimate is good enough and i should say that for very big capacitors like i'm holding in my hands here these capacitors i consider to be large as opposed to a little tiny guy like this the large capacitors are heavier they're more susceptible to vibration lead spacing is much more important for these for example if you have a five millimeter lead spacing and you buy a capacitor that has only two millimeter lead spacing then you're going to have to stretch out those legs right for them to fit into that wider hole which means that the base of the capacitor its little bottom here will not sit flush with the board and for a bigger capacitor that's a problem if you've only got a 1 microfarad 50 volt capacitor even a 4.7 microfarad those are pretty small for for the low voltages you're dealing with there and they can actually stand up on their legs i have a video about the se30 or macintosh se sony power supply and inside that you'll find a lot of those smaller value lower voltage capacitors standing up on their legs because they're so lightweight and small it doesn't matter but for the bigger capacitors you want to make sure they sit flush with the board in other words if they're a radial capacitor you want those legs to go straight down you don't want them to be bent out and that's why being able to measure with your calipers the appropriate lead spacing is critically important and don't just base it upon capacitance values either because in the same sony power supply for the macintosh sc and sc30 a 4.7 microfarad doesn't sound like much and it isn't a 4.7 microfarad capacitor that's rated at 350 volts is quite big it's it's maybe not quite as big as this one but almost and you want those capacitors because of their physical size to sit flush with the board and not standing up on their legs [Music] and the last thing before we get on the computer and take a look at the mouser website that i want to add is that you may not always be able to find an exact replacement that's especially true of older axial capacitors you may not be able to find that capacitance and voltage even a higher voltage if even after much much searching uh it may not be a case if it's just out of stock they may not make it anymore or you might be able to find one that's a tantalum that'll cost you six dollars or even 15 or something crazy like that i've seen them before that's really made for something that is not vintage computing maybe for the medical field or something like that you really don't want to pay that much for one capacitor but there are times when you just can't find any equivalent axial at any price and the good news is that you can use radials you can use the radial capacitor and just bend out the legs and i have one of my recapping videos that actually shows that i did replace some of the axial leaded capacitors with radials and i bend out the legs and usually there's enough length of those legs to where you can do that just make sure that you don't short out the legs across some other exposed piece of metal or trace if there is anything like that on the board then you need to buy heat shrink and insulate those legs before they go down into the board also be aware of the height because axials are very low to the board but a radial is much higher and so if you have very cramped space constraints you need to sometimes bend those capacitors lay them down flat and then solder them in that way so yes you can replace an axial with a radial or you you could replace a radial with an axial i don't think you'd ever want to do that but they can be swapped out that way [Music] okay friends here we are at the mouser website to begin i'm just going to give you a basic overview and compare with the digikey site the digikey site is largely comparable you can see it has a search bar just like mauser does up here but the differences begin when you start typing in something for let's say we're going to search for 47 microfarad capacitors 47 uf and it immediately says okay you want to search for capacitance or capacitance range and i want to search for capacitance and then it will do its thing now the only thing i really don't like about mouser is how long it takes to me that took too long it shouldn't take that long but that's a minor gripe other than that i really don't have much complaints anyway this is the screen that you normally see if you search based upon capacitors and you can see here all right do we want to search in capacitors and if so we click this and we can see there's 8 202 pieces so we'll go ahead and do that and then once we search within capacitors after it takes its sweet time then we have these categories here we can choose tantalum or polymer or ceramic and film aluminum electrolytic capacitors so we'll go ahead and do that aluminum electrolytic capacitors and then once we're in here then remember we talked about the different types you've got axial leads wires coming out the sides radial leads wires coming straight down surface mount then we've got a snap-in type then we have aluminum organic polymer so these are the ones that are newer tech which have lower esr but we'll just say okay let's go to the aluminum electrolytic surface mount capacitors and then we're presented with other details that we can further narrow it down now before i get into any more detail i'll just go ahead and switch over to digikey and we'll do the same thing and you'll see the differences right away microfarad and well it's not dropping down let me see if i can reload it and it'll drop down finally 47 microfarad sometimes it drops down and sometimes it doesn't oh well it didn't drop down this time so i'll just go ahead and search and then it gives me this screen we've got the different capacitor types that we can choose aluminum electrolytic capacitors ceramic and yeah aluminum electrolytic capacitors and then of course it takes us here and you can see it's somewhat similar you know here's digikey here's mauser switching back and forth so you got the manufacturers and and then of course the specific details and then if you were to pick i don't know just pick one at random then the product web page looks something like this and then if we just go down here and pick this guy at random it's not the same capacitor but we can kind of see the product page looks like this so the layout's a little bit different um i guess it's just personal preference it's largely the same just some subtle differences maybe it's because i'm just used to mauser i prefer it more but the datasheets are always here right you don't have to scroll to find the datasheets it's always here and then you can put your customer number this is the area that you can assign a label like you could say c12 if you're going to use this capacitor on a circuit board and then when you actually order it this will be printed on the label that's affixed to the little bag which is kind of nice and then of course you can put your thing in here in digikey you also have a customer reference so you can put whatever you want there and you know type it in to get to the datasheet it's it's eluding me at the moment but it's somewhere let's search for data not found okay well then uh you know i normally don't use digikey so that you digikey fans will will maybe spot it right away but i just i just prefer the layout of this better you know even though a lot of the things are the same and we can go back to our little list here and then of course it lets us further narrow down what we want and maybe the capacitor you're trying to replace is rated at 16 volts and if so that's this voltage rating section here you choose 16 volts typically capacitors are are 20 tolerance sometimes for other capacitors you'll see 10 percent even 5 here those are going to be more expensive you really don't need to go lower than 20 percent i mean it's not going to hurt anything if you want to pay extra for a 10 tolerance capacitor but for aluminum electrolytic capacitors anyway with the fluid filled electrolyte 20 is actually your only choice here but it's all that's all you need so if you're wondering about it you don't necessarily have to choose it you can just reset it and not select it but i just want to mention that because when you're choosing capacitors you'll sometimes see more than just 20 there i normally don't choose capacitors with esr so i kind of leave this blank and then for aluminum electrolytics i always try to have a capacitor that's 105. you know 85 isn't necessarily bad but this determines the life of the capacitor you can go higher if you want to pay more but going with 105 is perfectly fine and if you really really want to replace with an aluminum electrolytic capacitor which means you're going to have to replace it again in 20 years then okay you know 105 degrees is what you really should shoot for and only go with 85 if there's no other component in the size and capacitance and voltage that you want and then remember we talked about the actual physical size of the capacitor right this lets you choose diameter length height if you want to narrow it down that way so say we've got a a diameter of the capacitor that's limited to five millimeter then we can choose that and then of course over here it has life and typically you want to choose something a higher value to get a longer life there are some differences in esr between the hours so you might say okay well maybe it's better to buy two thousand dollar but honestly you know even if you compare the specs i personally would go with the higher hour parts for especially for aluminum electrolytics and then of course down here it says in stock so why would you want to see a list of capacitors that aren't in stock or an active i usually tick this mark too just to make sure it's not an obsolete product that you're going to be able to continue to find it and so on and then you've got this check mark here r o h s compliant r o h s compliant and you might wonder well what is r o h s and here we are the explanation of rohs which centers on lead-free compliance it's not simply restricted to lead but basically the the summary is the first sentence here it's designed to eliminate things that are dangerous to people and to the environment so specifically they want to eliminate lead and then of course cadmium and then all of these other little guys here including flame retardants and if you know anything about yellowing plastics uh yes i definitely want to eliminate flame retardants even if it goes up in a ball of fire a great ball of fire right man that stuff makes your plastics yellow anyway rohs is basically uh saying if you if you see an rohs compliant product then it's going to be free of lead in these other things and it makes your body happy and all that so then the question becomes oh it sounds good you know the more environmentally minded you are the greater it may sound and you might think okay well maybe that's maybe i want to check this checkbox but sometimes it'll cost you more and honestly if we're talking about soldering i i do not like lead-free solder i honestly would not prefer to have a completely lead free soldering environment and of course we're not ordering soldering here we're talking about parts like capacitors and so on so it's it's really the construction of these parts uh do are they constructed without any of these things and you know sometimes the leads may be tend and if it's rohs compliant then it's not going to be tend with let it solder it's going to be tanned with something without lead so it's really up to you i never checked this box because it's just not that important to me and i don't want to diminish the the ideals of those of you who who feel that protecting the environment is is very important because i agree with it too it's just a personal choice and again it it's going to perhaps limit the number of parts a little bit and maybe even increase the price so that's a choice that you can make whether you want it to be there or not and i normally leave these two at the bottom unchecked but again these are your choices on whether you want to do that or not and then once we have our filters set up then we can proceed to apply mouser again takes its sweet time here and wow it only found one part whenever it comes directly to a product page like this it means it only found one capacitor that meets our criterion so uh this is the only choice now that doesn't mean that there are are not other capacitors that might meet the criterion in terms of specifications uh we'll go back and say out of stock include those parts too and then apply filters okay well in this case it's well let's uncheck active and see what happens okay it's still the only part sometimes if you uncheck in stock and active it'll give you more parts down here that you can choose from but in this case our restriction of 105 degrees c 16 volts 5 millimeter diameter really restricted the part especially because we wanted only five thousand hour okay and so if we say give me all of the five thousand and two thousand hours in stock and active and apply the filters we'll see what it gives us here and now it gives us a list of parts quite a few of them actually there's no page 2 down here so these are it says here results are 10. so we have 10 different ones from which we can choose and then you can click the sorting here if you want to sort by price you can see one piece is 20 cents here's 36 and the price is going up but the thing is though and this is the other thing i don't really care for uh it sorts based upon the one-piece quantity sometimes 50 pieces or 100 pieces will be you know more or less expensive you can see 0.011 is here 400 pieces and point uh 142 is here so it doesn't it doesn't sort by the quantities higher than one it's it's a sorting based upon the price of one and you need to keep that in mind because sometimes you might have a board that requires 10 pieces of the same capacitor so you're going to get a price break and a fairly substantial one too when you order more than one and then you can scroll horizontally and see things like a capacitance and voltage and all that and usually if it's an especially low esr it'll say the value here it's 0.7 ohms and then of course it'll give you the information this is a 2000 hour so if you look at all 2000 2 000 2 000 so the 5 000 this is the only one and so that's why it jumped us directly to the product page because for this size and the other data this is the only one that was rated at um 5000 hour but the other thing is ripple current because this is directly related to esr ripple current here and the higher the ripple current the lower the esr is so you can see here that this is fairly low compared to the others right this is especially low here most of them are over 100 so this one has a pretty high esr it's only 39 milliamps ripple there and then back to this one you know this isn't necessarily bad and it really depends on what esr that you're shooting for and that kind of gets our story a little bit complicated here but basically whenever you're choosing capacitors that's that's how i go about it i take all of this into consideration and if esr really doesn't matter in your application then by all means go with the high hour part and then you can check out the data sheet and look more in detail at the individual specifications especially the physical size because as i told you before you need to measure not only your stock capacitors but measure the space around because if you cannot find the exact body size replacement capacitor that matches your stock one if your replacement is bigger then you want to make sure you have enough space to accommodate that not only physical space for the capacitor but also the pads you want to make sure those pads are going to match up with the feet here so you can solder it on without problem [Music] okay let's now take a look at the manufacturers this was another question that i was asked how do you choose between manufacturers or is that important at all well i think it's important but when you're buying from mouser and of course digikey a lot of the capacitors that are listed are the big name brands they're not chinese knockoffs or the low end brands that nobody wants and so if we just look at this list this is not a comprehensive list but for the capacitors that we've chosen here aluminum electrolytics for this particular 47 microfarad value we see panasonic that's japanese we see nichikon that's japanese i think most of you probably know this name it's it's quite a famous name in capacitors but panasonic you know it's on the same level really united kimicon is actually japanese and if you look at the united kimicon webpage you'll see that nippon kimikon which is japanese company is actually the parent company so this child company united kimicon is just the overseas distributor the distribution outside japan basically but united chemical is nippon kemikon essentially and it is japanese quality capacitors they may not be as highly regarded as nichikon and panasonic in the minds of some but really when you're talking about japanese quality it really does go from one company to the next panasonic nichikon united chemical you can really trust them all on the same level and look what we see here the most popular are those three then we go down here to leilan i don't know how to pronounce it lilon leilon that's taiwanese so from taiwan that's not necessarily bad mind you and in my own company we buy a lot of our products from taiwan instead of china because taiwan gives a higher eye to quality but it's actually much less to manufacture in taiwan than it is in japan but in terms of the famous names you know i mean lilon is is comes far after the japanese brands we already covered nichikom panasonic rubicon another japanese name and worth worth is german so there's nothing wrong with worth uh here's a worth capacitor they're typically this pinkish red color the markings on them and w e is is the marking on the capacitor itself i've bought many a worth capacitor you'll find them in my mouse or cards for many of my recapping videos and there's nothing necessarily wrong with them they they have they offer fewer parts overall than some of these big name brands like nichikon and panasonic and so that's really one thing but sometimes you will only find the worth capacitor when you're searching i mean i've been hit with that many times i'll be searching for a certain set of criteria and you know setting up these filters and the only one will that will be there is the worth so it seems like they i can't say if this is true or not but it seems like they're trying to fill a gap where the other manufacturers haven't made a part that's a certain size or certain specifications they they want to be competitive by offering that differentiating point hey hey we have this part where the other manufacturers don't and that's why for my analog board recapping a parts list you find a lot of worth electronic capacitors in there it's a good balance i mean price isn't so bad and and you can find a lot of high hour capacitors in this case it's only two thousand dollars but many times you can find very high high hour uh worth capacitors but german quality you know if you want to talk about quality german quality is very much on par with japanese quality so you can trust worth even if you may not be as familiar with that name as you are with something like nichikon let me now give you one practical recapping example this is macintosh se30 motherboard and you might say wow that's a little bit unsightly who did that and the answer is me this was one of the first recapping jobs i ever did on and it was the se30 motherboard and you might say well my goodness why in the world did you do it this way it looks terrible and it does look terrible admittedly it does it works it's electronically sound and i've seen other people do it somewhat similar to this most people actually do it in an inferior way they leave the capacitors these are radial capacitors by the way they leave the capacitor standing straight up on the legs and they don't use any hot glue i put hot glue on it because i didn't want the little pads to snap off anyway the reason why i did it like this is because it was my first recapping job that was before i had any exp experience buying from mouser digikey and i had some parts in stock some jamco i many many years ago i purchased some jamco capacitor cabinets little drawers filled with components and i had all the capacitors i needed so i just said well i'm going to give it a shot and see how it goes and it still works to this day yes and this is exactly how it looks it's well not beautiful but even though these capacitors are not niche cons these capacitors are probably some pretty low low wind chinese makes they still actually work they do and you can see here if we look here at this guy this is originally an axial that went here and i replaced it with a radio and there's nothing wrong with that you can actually do that you just have to make sure that the height isn't going to cause problems when you're putting the motherboard back in there there is a height limit and you have to watch out for that but all of these capacitors you know this one's standing straight up and there was no problem with that but the others i leaned down for reasons of better protecting them from breaking off the traces but also to make sure i had enough height clearance to get the circuit board back in and eventually i did another recap and this is one that looks more beautiful actually these orange parts in this section here are stock chips and the replacement tantalum parts that i have here are a nice yellow that kind of matches those and by the way these filters back here are also yellow so it kind of you know i don't know how many of you like color coordinated circuit boards but to me this looks very lovely and if we zoom in we can see here that i did replace the axial capacitors this at the time i this was my i think it was 2006. i didn't make time to look up when exactly i did it but it was quite a number of years ago and i purchased a capacitor kit from a fellow member of the 68k mla at the time and he included all the capacitors necessary all the tantalums and including these guys these radio these no-name brand guys and um both these capacitors work but uh i did the the easy way you can kind of see here a little bit of a clump of solder there and that's because i clipped off the old capacitor and left the legs this is a multi-layered board so it's difficult to get out to fully desolder those and i didn't want to risk damaging anything that was many many years ago and so i just used the existing legs in fact if you don't have a lot of soldering experience i would suggest you actually do it this way it'll save you not only a lot of time but you will avoid accidents too but really in terms of how you should recap this is what i deem to be a good recapping job and then if we look here is the back side of the board and on these components none of these need to be replaced because even though you see c74 c70 c standing for capacitors they are teensy tiny little capacitors that are ceramics and you don't need to worry about those those don't go bad every time and if you're wondering why this is burned it's because i'd sent it off for repair since i couldn't repair it myself at the time somebody else accidentally had his heat gun on the fritz and it did this but it didn't damage anything thankfully so that's all i will say about that but yeah on the bottom bottom side of the board you don't have to replace these components unless in a very very very rare case one of them is bad and the good news is you can find schematics online i'll put a link in the text description below for the sc30 motherboard i've actually never done a video on the recapping of an sc30 motherboard because all of my boards are recapped however i know i need to do one for you one of these days so i might as well just do some preliminaries for you by giving you an example of okay let's say i'm going to set out recapping this board you could go and go to a place like console 5. here's their website i've never purchased from them before but i know that some of you in the vintage mac community have and it's not just restricted to max but you know commodore 64 is whatever basically they don't have everything they don't have recapping kits for some floppy drives and i've recapped those before so you want to check my videos first because i probably have mouser carts that are not you know on here and these guys are not affiliated with mouse or they buy their own capacitors and and do that but basically you type in sc30 and then you'll see some power supply kits analog power supply you can buy torques from them they are not sponsoring this video and again i've never purchased from them before i'm just mentioning it because many of you know who they are but you can see here main pcb means motherboard it means logic board and what they have two different kits one is an electrolytic kit why you'd want to do that i don't know okay i know you want to make it look stock okay so fine you can use that it's cheap right six dollars i mean you know these guys they have very competitive pricing i'll give them that and then you have the tantalum capacitor kit which is these beautiful little capacitors just like i showed you and you're going to be paying about double because tantalum are more expensive right you can pay pay by paypal and all of that you you should write them and ask them you know what exactly are the part numbers that you're using but i'm sure that they are quite comparable to what i used here and these are solid tantalum capacitors and you can know that because on this this little mark that looks like a letter a it's all filled in it's solid colored and they have polymer versions that are not solid and i'll show that to you on mauser in a few moments but i've already recapped this with tantalum capacitors but this one is kind of a bad job so maybe i should recap this with more beautiful capacitors however i will just say that there's actually a problem here not a problem and functionality all these years it's worked fine it's still working fine to this day even with lots of ram and lots of accelerators working in it i've never had a problem with these tantalum capacitors i say that to the chagrin of tantalum haters yeah there are a lot of highly experienced technicians and even engineers out there who hate tantalum and you will come across those people in the online forums but if tantalums were as defective as tantalum haters say they are they wouldn't be sold today you just have to be careful voltage spikes can kill these guys and when they're killed they fail in a short circuit and they burn yeah flames will come out so it could actually damage some of the surrounding components too and that's why i wanted to say there's actually a problem here because there are 47 10 pieces of 47 you'll see here 476. ten pieces of four seven six on there and five of those actually see twelve volts the other five pieces only see five volts so there's a voltage issue so i'll show you the issue here on the mauser mouser site let's let's choose tantalum capacitors this time we are i did another search here for 47 microfarad and we want to do we want to look up the same type of capacitors that i use for my recap which are solid smd and then we can see those parts 476 is telling us 47 is 47 and then the voltage is 16. and then we're going to choose 20 percent here in stock and active we'll go ahead and apply those filters we can see that we've got some avx parts here we can go ahead and limit that to avx actually so i'll go ahead and just do one and by the way the you know that's i don't really like this but this is definitely if we can search for 47 on this page here see it's 47 microfarad 47 of the part number but they're showing a 68 there so this picture isn't exactly the part okay but we'll take a look inside the data sheet for those capacitors and we can see here the avx logo is filled in if it's not filled in then it's a polymer version of the tantalum capacitor and that is important because there is something called a d rating now here's the avx website it's saying that the d rating for solid tantalum capacitors is 50 and then we have polymer capacitors have only 20 now what is the d rating well let's go back to this page it says here the voltage rating of this capacitor which is by the way the same capacitor as these here these are rated at 16 volts just like this this means that's the maximum voltage rating of this capacitor of these capacitors and so a 50 percent d rating means you cut this in half you multiply it by point five you take fifty percent of sixteen what's half of sixteen eight okay so that means you can get a maximum of eight volts on this to remain within its manufacturer specifications any voltage that's higher than that goes outside the manufacturer's specifications and basically increases the failure rate it's still fairly low but you're increasing the risk of a fireball that's a 50 d rating now we just read polymer capacitors polymer tantalum have a 20 d rating what does that mean multiply this by 0.8 okay so that's what 12.8 so you can safely run 12.8 volts continuously across the polymer version of this and it'll be just fine so what's the problem well i when i did this this is way back when and there was a guy on the 68k mla who's you know he's a friend of mine i'm not saying anything negative against him there wasn't sufficient research done at the time to determine the voltage across each of these capacitors but i did the the research in you know schematic since we have a schematic i checked it all out and five of these only see five volts five of the ten but the other five see 12 volts and that's a problem now three of the five we'll see 12 volts almost continuously two of the five are the audio circuit capacitors and they will only see peaks of 12 volts but still they'll see 12 volts and so it's necessary for reasons of being within manufacture specifications to better ensure that none of these capacitors were ever are ever going to go up in a fireball to replace the five in question and i'll give you a list later on in this video but to replace the five with polymer versions so we would choose on mauser tantalum capacitors polymer and of course we want surface mount and we know that the voltage across the seven on this board what's coming in is 5 volts and 12 volts it can be a little bit higher than 12 it's not going to be 13 might be 12.6 but it's not going to be 12.8 and so we can say all right if we get a 16 volt polymer capacitor then that's going to fit you could go higher assuming that the case size will fit the pads and that is really the key because this is just about in terms of the length of the capacitor it's just about seven millimeters and so if we go up in voltage you probably can go up as high as 20 but we need to make sure that we choose a capacitor that will be solderable see this guy here this guy is he's made for wave soldering he's not made for hand soldering so the pads are on the bottom you need a little you need a metal piece that comes out on the sides so you would not want to choose this guy but this guy here is a different matter altogether he is this is kimit brand so he's in black but basically it's the same type of capacitor i have here you've got this little metal part that comes out the side so your solder can flow onto him and this is the type of capacitor you want so this is about four millimeter height here so you this is all part of the process folks you know just like here you can see looks like a top of an h here right that's enough in fact that's exactly how these capacitors are shaped so when you're when you're choosing your replacements you need to give due consideration of of that to make sure that the size of the capacitor is right all we need is 20 and i'm not going to worry about the temperature because 105 is the minimum here and it says what's the height you know of the capacitor that you want obviously if it's really really one of these skinny guys it's not going to it's not going to solder in there very well so we can actually set that i'll put it in stock active and we'll get these and see what it does and let's take a look at the avx okay so we've got one in the i mean color really doesn't matter folks i don't give too much of an eye to it but if i if i want one i can do that it says it's polymer but this picture is wrong i told you it was wrong before on the other one so don't go by the picture folks don't go by the picture go by the data sheet and the specifications that's very important if we look at the data sheet on these guys you can see here look at the polymer logo right you can see here it is just an outline whereas this guy he is solid so solid tantalum has a solid star trek logo basically right it looks like a star trek badge there from the original series uh and this this is not solid it's more of a hollowed out looks like somebody's going to write the letter a except they don't put the little horizontal line in there that's polymer so that's how you tell the difference between the two just by looking at the circuit board if you've got a circuit board and you know it's avx then this is a solid tantalum this is polymer tantalum polymer tantalum has the eighty percent d rating so if we compare the solid tensile esr it's 200 milliohms which is less than your aluminum electrolytics by the way and the polymer is lower still at 70 milliohms now this isn't the absolute lowest you can go even lower if you get something like ceramic you would not want to recap your sc30 motherboard with ceramic because ceramics are you know they're very expensive at high capacitance sizes and they have a voltage derating that is well we'll just say very very restrictive so you would not use ceramics for these you basically only have the choice of solid tantalum polymer tantalum or organic aluminum electrolytic which is polymer aluminum electrolytic or regular uh electrolytics but anyway these this 70 milliamps is quite low a ceramic might give you as low as eight eight milliohms maybe even five but you don't really need that low because the stock capacitors were quite high probably close to an ohm or a little bit more actually but i'm just saying that the polymers are going to have lower esr which overall in in this particular application is a good thing however there is something called leakage current and on a solid tantalum capacitor it's very comparable to a aluminum electrolytic with fluid inside it's very low 7.5 microamps is nothing folks it's really really tiny but the polymer is 75 yeah you read it right 7.5 versus 75. so it has more leakage will it matter well in this case no because we're talking about an sc30 motherboard that's plugged into wall socket power it's not a battery powered board but whenever you have a battery-powered device like a smartphone leakage current is going to be draining your battery faster so you know there are other considerations too that it might affect something but i have done the circuit analysis and this leakage is not going to affect the sc30 motherboard at all so you don't really need to be concerned about it we can see here the length is 7.3 millimeters so both are 7.3 in terms of the pricing you need 10 so we're going to look at this solid tensile 1.35 interestingly enough polymer is cheaper 1.29 you know i didn't go through all of the other variants of solid tantalum and before you actually buy something you want to make sure that you're getting the i don't want to say the cheapest one but the one in the price range that you want in accordance with the specifications that you have so probably if i go through the list i can find one that's a little bit cheaper than this in the 10 piece quantity that has the same the same specifications yeah packaging plays a role folks so it is possible to find some cheaper ones but in this case between these two capacitors this you know you're going to need to expect to pay for tantalum more than a dollar that's for sure when you buy these here is the 68k mla i started this thread on december the 10th 2020 and this if you want to read it i'll put a link in the text description below for you but basically it covers the audio system which is what the schematic is talking about i also talked about the d rating in detail and i also mentioned that these five capacitors c1 7 8 12 and 13 only see 5 volts and the other capacitors c9 and c10 are definitely out of spec because they see 12 volts and then later in the thread we determined that c3 c4 and c5 also we'll see 12 volts so c9 10 3 4 and 5 are the ones that need to be polymer capacitors polymer tantalum if you're going to recap with tantalum it's very important to use polymer for those five and honestly if you're starting fresh and not just fixing a board like this buy all of them polymer including the one microfarad guy get all of them in a polymer tantalum and that way you know if you buy five solids and five polymers you're gonna get the one piece quantity price so you wanna you want to buy 10 where possible to get that lower price point and again don't forget you know ignore this picture it's annoying me i'm upset about it i wish mauser would put the correct picture there but they don't so don't let this confuse you please don't let that confuse you and then you can put it it limits the characters quite a bit but i understand why they do it because they only have a certain amount of space but you can say sc30 and then see whatever i i don't know if they will see okay so that's that's all the characters that will let you do these are not the capacitors that i that you need to change out i'm just showing you there's a limited number of characters there so you can put in whatever customer number you want but you could just say sc30 47 microfarad caps and actually you may not even need to say that at all because it's pretty obvious on the on the package it's going to say that these are 47 micros but if you're buying a lot of different capacitors for a lot of different projects it's probably a good idea to include sc30 in there when you purchase and then when you want to buy then you can put your multiple there and it tells you the extended price and then you click buy and it'll add it to the card and the last thing i'll say there's a lot more i could say about mauser but i don't want to make this video too long and bore all of you so um neobium oxide i've done a video on these basically you can use these and these are preferred over 10 over solid tantalum it's kind of like using polymer except these are even better because the failure mode of these is not a short circuit polymer capacitors have a failure mode that's better than solid tantalum in that it usually will result in high leakage current but still sometimes you might get a short however they usually don't go up in flames these will be a dead short definitely and they will go up in flames and what triggers it is over voltage but if the neobium oxide capacitors see an over voltage case they're not going to go up in flames and they're not going to be a dead short so you might say why can't i use these instead of tantalum everywhere and the reason why is because they're limited to about 10 volts so most of the time you can't use these and for for reasons that i won't go into into detail you you don't really want to use the ceramics either film caps can be used on certain like the analog board on a sc30 or something like that i don't want to give you you know this video is how to choose uh parts but basically film capacitors are for really high voltage applications as opposed to what we're talking about now in this example for of the sc30 motherboard which is 12 volts and 5 volts so it's really unnecessary and you wouldn't find the parts that you need there and they'd be too big anyway so the last thing i'll say is um for the what about polymer capacitors now we just talked about polymer tantalum right but what about aluminum organic polymer you can recap your sc30 motherboard with these you'll need surface mount and you want 16 volts and we don't need to choose esr and the minimum temperature is already 105 and then it's just a matter of choosing the diameter to know what you want and then you can choose say if you want four thousand hours in stock active apply and see what we get and it says there's only one cap that will be suitable and it says diameter is 5 millimeters length is 5.8 okay 4 000 hour ripple current 550. so uh overall esr 80 milliamps so this is comparable to the polymer tantalum polymer tantum is a little bit lower than this and really you know it's going to give you a stock look if we look at the data sheet okay that's what we have to worry about this is the only one it gave us for that criterion and it's a hybrid hybrid means it's not solid this is a hybrid electrolyte so there is it's polymer but it's liquid and it's going to be very similar to the electric liquid electrolyte aluminum electrolytics in that eventually this liquid electrolyte is going to even if it doesn't leak out it's it's going to have it's going to limit the life of the capacitor now 4000 hours is a long time but compare that to a solid electrolyte which has no fluid in it at all and can theoretically last as long as the life of the motherboard right the these polymer aluminum electrolytic capacitors do come in a solid type without the word hybrid and if you can find those then yeah recapping with those would be fine but i would not if you have a choice between polymer tantalum or polymer hybrid aluminum electrolytics for recapping something like the sc30 motherboard which would i choose i would definitely go with the tantalum i don't want a fluid electrolyte so but don't let the shape of the can fool you the same shaped capacitors can also be found in a solid electrolyte you just have to search for it i just wanted to mention that on this video so that you are aware of it if you're thinking okay i want the stock look what are the caveats to that and that in the caveats are well you might only be able to find a hybrid type and it doesn't say the word i'll search for it yeah it doesn't say it here at all so definitely definitely before you buy anything always check the data sheets right because the data sheets will tell you that important piece of information and of course as i showed you before don't follow the picture on the mouse or webpage follow the data sheet picture and so this logo is going to confirm that you have a polymer capacitor and then you can set out to recap your sc30 motherboard i will give you a mauser cart for the sc30 motherboard that includes polymer tantalum capacitors for all 10 pieces of the 47 microfarad and then of course this little guy here at c6 as well so that you can get started and as far as i know everybody who does tantalum uses these solid guys and that's a problem for reasons i just mentioned so i think this will probably be the you know there are other people who use polymer tantalum capacitors but many of them just use it because they assumed it would be better but there's actually good reason for it you know some of them see high voltage and there is a 50 d rating and so there are a lot of considerations when you're going to get on mauser and you're going to start looking for capacitors and it's difficult to to cover every possible case in this video but i would say that if you have any usage questions that i've not mentioned already please leave a comment down below and let me know your thoughts and there you have it folks if you found this video useful please consider giving it a thumbs up if you're not already subscribed please subscribe if you'd like to support this channel we have a paypal link in the text description below feel free to offer your comments and feedback any questions you have in the comment section i enjoy engaging everyone in the comments section i'm not one of those youtubers who ignore people who make a comment i try my best to read and reply to every comment actually so i'm happy to engage you there i cannot guarantee that i'm going to be able to solve every problem you may have just keep in mind that this video is giving general advice on how to recap your boards and recapping is not a magic solution for every type of problem but for many type of boards it is it can actually restore your vintage electronic device into usable condition again thank you for watching and i wish each and every one of you a great day

Channel: JDW

Views: 54,289

Keywords: choosing capacitors, recapping, vintage computers, Macintosh SE/30 motherboard, Mouser, Digi-Key, Tantalum capacitors, aluminum electrolytic, voltage derating

Id: 6PKaj9-1xIs

Length: 72min 55sec (4375 seconds)

Published: Thu Dec 24 2020