Choosing Capacitors to Recap Old Electronics

Learn how to select capacitors [caps] for recapping old computers and vintage electronics. Understand which caps should be replaced, what the top brands are, how to use the Mouser website and evaluate the capacitor specifications. See how I pick caps for the Macintosh SE/30 motherboard.

🔍 INDEX
0:00 Intro
2:47 Which Caps to Replace
7:53 How to Choose Replacements
10:29 Measure Capacitance with an LCR Meter
13:15 Measure Physical Size with Calipers
18:45 Substitute Radials for Axials?
20:49 Buying Online: Mouser & Digi-Key
28:27 What is RoHS?
36:06 Capacitor Brands
40:05 Practical Example: SE/30 Motherboard
1:06:50 Organic Polymer Capacitors & "Hybrids"
1:11:50 Closing Words

🛒 SE/30 MOTHERBOARD CAPACITORS
I changed my mind. Rather than give you a Mouser Cart for the SE/30 motherboard, I instead provide links below to individual capacitors on Mouser. That gives you freedom to choose a Can-shaped capacitor for a stock look, or your favorite tantalum. The links below also let you choose the proper lead spacing for C11, which varies by motherboard version (2 types).

There are ten 47uF caps on an SE/30 motherboard: C1, C3, C4, C5, C7, C8, C9, C10, C12, C13.

I dislike liquid electrolytes, so I personally won't use Polymer "Hybrid" Aluminum Electrolytics; but I listed that Hybrid cap because it technically will work fine and is superior to a regular aluminum electrolytic.

👉 For the "stock look," go with the "Panasonic OS-CON." They have the lowest ESR, but leakage is twice Polymer Tantalum.
👉 Want the lowest Leakage Current? Go with the "Kemet SOLID 25V Mid-height."
👉 If you want the safest Tantalum below, in terms of being safer from a voltage spike that might kill the cap, the "AVX Polymer 25V Full-height" is ideal, albeit a bit pricey. Even a 16V Polymer Tantalum is "safe" with the SE/30 motherboard's 12V though, so technically any of the Polymer Tantalums below are fine choices for that application.

47uF 16V Polymer Aluminum Electrolytic Caps:

47uF Tantalum Caps:

✴️ NOTE: CAN-shaped Polymer Aluminum Electrolytics like OS-CON have higher leakage current than Polymer Tantalum, and much higher leakage than Solid Tantalum or regular fluid-filled Aluminum Electrolytics. That leakage spec doesn't matter for the SE/30 MB, but is an issue in circuits where low power matters, like battery-powered devices.

Remaining 3 caps:
Choose only 1 of the following for C11 because there are 2 Lead Spacing variants (check your SE/30 motherboard to find out which you need):

⚠️ There are 13 caps in total on the SE/30 motherboard: 10pcs of 47uF and 1pc each of 1uF & 470uF & 220uF. The 4pcs of 47µF which see 12V are: C3, C4, C9 & C10.

🛒 Amazon (US) Affiliate Links:

⚠️ SOLDERING ADVICE! Keep your 300°C to 350°C soldering iron time to 3 seconds or less for either side of the capacitor, especially for Polymer types! The Polymer very slowly degrades over time, but heat accelerates that degradation!

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#capacitors #electronics #MacintoshSE30 #JDW

[borayurt]

Tons of info here, very useful. But, why not talk about other critical properties of capacitors like ESR? Also, why not talk about properly testing a capacitor to see whether it really needs replacing? Not all caps puke electrolyte when they go bad, and not all of them lose their capacitance when they go bad. Actually, it is very common to see capacitors go up in capacitance when they go bad. This is of course not an actual increase in capacitance but a metering error (if a less than ideal tool like a DMM is used) due to electrical leakage, which is another common fault in aged capacitors. It is very easy for a novice person to measure a 100uF cap and see that it is reading 110uF and decide that it is still good.

[santospoland]

The significant notes are a signature of the amazing attention to detail and considerations you make to your craft. Thank you for sharing all of this with us. Your work is a treasure!

[cberge]

If you aren't able to determine the original voltage raring of a cap. Look for other caps on the board that are in parallel to the one being replaced. The voltage rating on those would be the same as the one in question.

[johnmitchell]

Words cannot describe my appreciation for you taking the time to make this video and explaining it in layman's terms for a novice like myself to understand 👍Tons of valuable information that I can come back to as needed

[fritzj]

Great tutorial. You can also measure the resistance or microhenries of the inductors with the MESR-100 ESR meter. The reactance formula is 2𝛑FL. That would be 2 x 3.14 x frequency of esr meter which is 100 kHz x 100 (uH) Just plug it in to get the reading.

For resistance R=0.628 X L(uH)
For Inductance L(uH)=R(ohms) ➗ 0.628

[threethousandyen]

Great overview! Digi-Key does let you sort by price at quantity. Really great to find discounts if you plan to recap multiple machines.

[retrocomputinggrotto]

Very well explained! Anyone just starting to re-cap old(er) electronics should watch this :)

[JDW-]

Wishing a very Merry Christmas to all my fellow recappers! 
✝️🌟❄️☃️🎄 🎁 🎅🏼

[buriedbits]

This is a video I always come back to. Thank you so much for putting this video together.

[allanknox]

Any cap in a power supply should also probably be checked for ripple current as well. Mouser and DigiKey will help you find almost anything if you use their customer service sales guys.

[sketchpalosotherchannel]

Just recapped my IIsi today, it's working! all I need is a monitor and peripherals and I will finally have a really nice vintage mac. I unfortunately had not watched this video at that time, but here I am now. I did buy the logic board caps from amazon, but the power supply board caps are from Mouser.

[gyrgrls]

Every great tutorial deserves a recap.

[davidgreen]

Thank you for making this video! I found the information within it to be very useful.

[TradeWorks_Construction]

Great use of Mousers site to illustrate the thought process used toward picking out a replacement option. I prefer Mousers site myself and thought i would throw my 2 cents in about one of the features I love.

This may have already been mentioned by someone else but Mousers site actually will show how many fit your criteria BEFORE you hit apply.

At the Far left of the screen under the Products Section in Blue it keeps track of the shown RESULTS # —> To the RIGHT in RED it keeps track of the current results remaining according to your filters.

To actually view those results you still need to click apply filters however it’s a very helpful tool to know ahead of time which filters you’re choosing might be excessively limiting your options.

ESPECIALLY if any of the filters were preference and not strictly necessary for the operating criteria.

[AladimBR]

Very helpful. Thanks for sharing your knowledge. I'm a mechanical engineer and electronics are not my expertise. Despite that, I've always been interested in computers and have build my own machines since 386/486 days. At high school, I had an Apple II+ plugged into a 26 inch Philco TV (valve tech), which I had to "dispute" with family. A lot of nice memories. Anyway, I have some retro stuff at home: kept P2, P3 and some Athlon XP mainboards, plus 3dfx video cards, and an Apple II plus, IIe and IIGS I've collected over the years. Most of these boards (and some PSUs) need a recap job. I've trained over the last year on junk electronics (meant to scrap) in order to learn how to weld and now I feel confident I can do it. I decided to learn this skill because many things break at our homes due to failing/ageing capacitors and most business just want to replace parts, not fix. A total waste and very hard to keep our loved retro stuff working. That's how I've arrived at you video. Watched 2 times already. Made a list of the capacitors I need and have browsed over mouser.com. One thing I didn't get, it is how to choose capacitors for these mainboards concerning ripple current and ESR: what should I pick? If I understood correctly, ESR is ok if not too high, but it doesn't have to be the lowest also. What about ripple current: low or high? That was not clear to me. Hope you or someone reading the comments can clarify that.

[brycelynch]

Console5 is my go-to for getting recap kits. Not getting paid to say it, they're just awesome.

[sierrawhiskey]

Many thanks, I'm a middle aged guy curious about recommissioning the 70's Hi-fi gear I grew up with and recently inherited from my fathers estate.
It's a pity more people don't realise much of this vintage stuff can be salvaged.

[micinput]

There's one useful source of information you didn't specifically mention. Often you can track down "service manuals" for your equipment. This is usually the source for the schematics, but "service manual" is usually a better Google search term. Even if the service manuals only have block diagrams, they sometimes list the "bill of materials". For example, I have a music studio effects unit from Lexicon, and its service manual lists all the capacitors used, their specifications, how many of them there are, and what they are labeled on the silkscreen on the motherboard, i.e.:
"CAP, ELEC, 22UF, 25V, RAD 4 C27, 28, 31, 104"
Having watched your video I can now interpret that as "Capacitor, electrolytic, 22 microfarads, 25 volts, radial. There are 4 of them, specifically the ones labeled 'C27', 'C28', 'C31' and 'C104' in white on the motherboard." I'll still need to measure them with calipers, but I'm a lot farther into identifying replacements than I was before.

[xrayxxx]

Glad to see this. I am restoring a TEAC A-7300 Reel to Reel. Has the original rubycons and others in it from 1973-1978.

[xaviergonzalez]

Thank you Sir! My native language isn't English but I get you at 100% great video that no one talk about it!