Let's recap a Macintosh Classic II motherboard

BONUS CONTENT for the Mini Mac Repair-a-thon on the main channel. In this video I just recap the Macintosh Classic II motherboard. Final testing of this will be on the main channel in part 3 of the repair-a-thon.
-- Video Links
Mini Mac Repair-a-thon:
Part 1: • Three unknown Macs: Le...
Part 2: • Not so fast! I hit som...
Part 3: • The troublesome Mac Cl... (where this board is tested)
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Elenco Electronics LP-560 Logic Probe:
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Hakko FR301 Desoldering Iron:
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EEVBlog 121GW Multimeter:
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Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
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RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
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--- Links
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--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
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[@adriansdigitalbasement2]

I realize I called the brain "Chip Quik" when it's actually "Chem Wik" LOL! I just had Chip Quik on the brain for some reasons and didn't even notice.

[@jandjrandr]

The reason the ceramics lose capacitance with voltage is due to saturation which resists the influx of electrons because it is just filling holes. This is less of a problem with electrolytic capacitors because they act more like batteries storing the charge chemically.

[@DiverCTH]

I'll take the blame for flogging ChipQuick for recapping and other desoldering work.

[@computer_toucher]

Brain farts are always fun if you catch them haha

[@jeromethiel4323]

@@jandjrandr Incorrect. Capacitors store charge electrostatically. Like a leyden jar. The dielectric is formed electro-chemically.

[@JamesPotts]

The solder-techs at work use Chem-Wik Rosin braid. Great stuff.

[@niino4329]

About the vinegar: The issue with electrolytic capacitors is that the chemical properties of the electrolytes used in them differ a lot between types and series. There's really no one-size-fits-all approach for dealing with leaked electrolyte (unlike most batteries). Some are slightly acidic, some are slightly basic, some are corrosive, some are not, some contain a lot of water, others don't etc etc.

[@Darxide23]

I've been commenting this in virtually every video where he talks about it and then asks for suggestions. Alternating vinegar cleaning with a little baking soda+water should ensure a more neutralizing finish. It won't be perfect, but it will get you close. These aren't mission critical projects, so close enough is good enough.

[@leosmith848]

@@Darxide23In general when cleaning random things I use a weak acid - in fact te witches brew used to clean showers works well, as does citric acid descaler, and for acid cleanup, weak bleach or baking soda. Then an alcohol takes off any grease

[@BlueBarnTech]

I love that you have gone back "old school" for a bit and really shown the process in your last couple videos. They happen to be perfect for me as I am in the middle of my first full recap on a Mac IIci.

[@robertclark8351]

Fishy smell = Zinc. Zinc is a major component in electrolytic capacitor tech, by inference.

[@mikebarushok5361]

Also, potentially the insulating paper on the bottom is impregnated with oil, which could be literally fish oil or an asphalt mixture that uses fish emulsion.

[@FernandoelChachi]

Just to tell that I love videos just soldering/desoldering caps or chips, so do not think that you've already shown that . They are very relaxing: ASMR for me.

[@InssiAjaton]

Here are some thoughts about the cleaning. I start with a very recollection from an ancient TEK tip. I don’t recall whether it was some TEK publication, or a story in a magazine. But it described what TEK does to instruments that come to them for service. The first operation (after paper work at the receiving, of course) was to remove a few panels and put the instrument into a dish washer, along with dishwashing liquid. The rinsing was, or at least ended with distilled water. Then there was drying - several hours. That was followed with a detailed inspection. Finally actual troubleshooting, repairs and calibration. Often times the repair step turned to be unnecessary! My own advice is not to trust the IPA, or any other evaporating substance for last cleaning step. That is, because whatever it did dissolve, does not evaporate with the IPA, it is just left behind!!! Water has some of the same behavior, although to a much lesser degree. So, you should FLUSH the board, or alternatively WIPE it as dry as possible. Small areas can possibly be handled with a clean, dry Q-tip. Larger areas best with a paper towel.

[@ralphshoop8822]

Adrian, if you ever start a band, you should call it "The Wiggle Method"!

[@pipschannel1222]

It somehow always reminds me of that nineties song by The Outhere Brothers 😁

[@rommix0]

The only problem is he'd probably get sued by The Wiggles for having a name too similar to theirs.

[@jdenslinger]

@@rommix0 then we need to just make him a millionare, so he can just buy the wiggles. *nods*

[@scottharvey-davies1607]

The Wiggle Method and their smash hit "lets get right to it !"

[@scottharvey-davies1607]

and the 'B' side (remember them) "Without further a do"

[@DeputatKaktus]

I used to not care that much about flux residue. But: When on a retro computer camp in 2023 I had some REALLY weird issues on an Amiga 500 that would come up with completely random error screens on each powerup. None of it made sense. I was able to narrow the issue down to the aftermarket RAM expander and thought maybe that had some connectivity issues or whatever because the system behaved normally without it installed. Friend of mine had his fancy soldering microscope with him. He checked the expander inside and out, and electrically there was nothing wrong. All the connections were solid and there were no interrupted connections at all. But almost in passing he mentioned that maybe giving it a good wipe with IPA might help get rid of some flux residue. Because he remarked that sometimes, despite what everyone and their dog will tell you, flux DOES conduct electricity. Not a lot, mind you, but still - maybe it was enough to screw with the rest of the system. So I figured "Why not?" and gave it a shot. Lo and behold - after a good IPA scrubbing the issues were gone.

[@jeromethiel4323]

More likely it was dust and other contaminants sticking to the flux. It is sticky and tends to collect dust. You should always remove solder flux. It's just the right thing to do.

[@blazini]

This is true. I design alot of random PCBs and a few times I've tested them right after assembly without cleaning. Since they're new designs it's easy to attribute problems to mistakes but I've gotten duped by "no-clean" flux conducting between pins.

[@sampoturunen9337]

Adrian Ross and happy little capasitors 😅

[@brunorbf]

I remember reading in the early 2000's, regarding leaked motherboard batteries, that one should use white vinegar mixed with baking soda in order to neutralize the leakage. Sometimes I still use that mix. Either way, after the vinegar it is as you said: wash it and/or clean it with alcohol. I prefere to use alcool, after the vinegar, if it is a small area. For a full recap, on a leaked motherboard, I like to use an ultrasonic cleaner. Before I bought the ultrasonic cleaner, I washed the motherboards with water and dish soap, scrubbing it with a toothbrush.

[@nodaitsu]

I love how you seem to take genuine delight in every part of the process, from Freakin Works to electrolyte carnage and grime. Working my way through your videos now, and I'm learning quite a bit. Thanks for the fun. I'm someone that went to trade school for electronics and it's amazing how many repair and construction fundamentals weren't really covered. Troubleshooting and theory, sure, but who'd ever need to solder when you can just replace whole PCB modules? I guess that was the thinking, anyway.

[@Madmanguruman]

It's the ceramic dielectric material which is primarily responsible for the capacitance roll-off due to DC bias. Class 1 dielectrics are mostly flat under DC bias. Class 2 dielectrics have significant roll-off. Look for C0G (NP0) dielectric as opposed to X5R / X7R if you are not interested in decoupling (ie if you are replacing larger ALEs).

[@jeromethiel4323]

I was wondering. The ceramic capacitor i am most used to all the old disk type, and they were really only effected by ambient temperature, and not much by that. They were the epitome of stable capacitors. When Adrian showed the manufacturers curves, i was WTF?!? It's real, but why? And you provided the answer. So thank you for a very good and informative post. This is why i read the comments, for little nuggets of learning like this.

[@Madmanguruman]

@@jeromethiel4323My pleasure. I worked for a large Japanese conglomerate for almost 15 years. They specialize in MLCCs and this stuff was my life for quite some time.

[@ASMRPoohbear]

Great video. Loved watching this process like this!

[@brianhginc.2140]

Hello Adrian. Over-sizing your ceramic caps in some situations may be a bad idea. I know at the voltage they will eventually run at, there is a loss of capacitance, however, when powering up, your power supply will see the full double capacitor capacitance you have chosen since the caps are starting at 0v. Do not worry about your current mods as so few caps shouldn't affect a power supply which usually has extra head room, but if you had a motherboard with 200x10uf caps where the power supply was used to seeing 2000uf at powerup, now with your 22uf caps, it will see 4400uf at power up. On the re-capping I have done in the past, I've used modern tantalum with an over-voltage spec. IE: for a 5v supply, I've chosen 16v tantalums and for the 12v rail, I've used 25v tantalums. As for cermaics, purchase X7R caps in a larger package / higher voltage and at 5v, you will loose only 1-5% of their rated capacitance instead of 20%.

[@jasmijndekkers]

Hi Adrian, Great job yuo did again. Nice to see you work on this hardware. Greetings from Steven from the Netherlands

[@warrenbullock3165]

Thank you Adrian for another great video. I’m in the process of recapping my working Classic II.

[@donkeymedic]

The white stuff mostly oxides. Aluminum oxide and tin oxides. Any solvent will typical clean them. Some say denatured alcohol works better then isopropyl. Denatured is ethanol like you drink and typically a kerosene or mineral oil. Usually in paint section at stores. I like isoprop. The residue gunk is burnt flux. The chem bread has some more flux in it. Isopropyl will make it flux-y again.

[@necro_ware]

Instead of vinegar you can take lemon juice. It works the same, but smells a lot better.

[@Mr_Meowingtons]

lemon fresh!

[@Peter_S_]

You're better off getting some raw citric acid powder and making a solution of that. Lemon juice contains organic residue, but it does smell nice. When I worked at an Apple authorized repair center, we used to buy lemon extract from a bakery supply company by the gallon for case cleaning. Works excellently.

[@ray_mck]

I'm not sure I'd like the sugars in fruit in my electronics.

[@necro_ware]

@@ray_mck I mean of course concentrate without sugar. I wouldn't drink that :)

[@ralphshoop8822]

@@Peter_S_ citric acid is nice for cleaning appliances and stuff if you have hard water, and it's cheaper than vinegar.

[@richardbrobeck2384]

Great video Adran !!

[@NickCharles]

Thanks for going through this, it's very informative! I've a Power Mac G3 mini tower with similar SMC capacitors, and an LC power supply that I need to recap myself, I'm taking notes for when I'm ready to tackle those projects!

[@JoshBattin]

FYI at 6:48 when you said "Not by the wiggle method" my brain went here: "well naugh, that thear wiggle method never did nobodah no hawm" *said in a deep southern drawl. and an 8-bit dance party broke out...yeah.

[@johnathanstevens8436]

I too enjoyed the twist off method, it seemed to be the cleanest way to get the old caps off with the least stress on the board. I think the secret is the downward force to keep the legs in place while disassembling the can.

[@snowdog993]

The reaction of the vinegar with the motherboard is nearly like mixing vinegar with baking soda. The bubbling is the alkaline dissolving from the vinegar. Using that method does neutralize the PH but if you leave the vinegar on too long, it could eat away just as much as the alkaline. That is why you should use isopropyl alcohol to clean the board. You could even wash the board with soapy water and rinse thoroughly if you don't have isopropyl alcohol. Yeah it looks icky, but it is very satisfying to see the end result.

[@TzOk]

Vinegar is a weak acid, thus it is good for neutralizing leaks from alkaline batteries, which are base. Though, I don't think this is the case with the electrolyte from capacitors.

[@anthonyblacker8471]

Talking about the wick and all.. man Adrian it really REALLY makes me miss Radio Shack. I know Micro Center has a pretty nice stash of parts and the like, but man there was a Radio Shack in EVERY town when I was a kid and they had EVERYTHING back in the day.. like ANY part you could THINK OF.. and if they DIDN'T have it, within 2 days they could get it for you. There's still something I truly miss about the experience of going to the actual STORE and talking to the people who work there about my project or whatever I'm working on.. and perusing the parts myself, deciding on anything new or extra or whatever.. it's just, that's a lost thing today. Maybe Amazon or eBay or the China market stores like AliBaba or whichever, they're great and all, but you don't know exactly what you're getting, the quality of it until you feel it.. and with chips, man.. you can get whamboozled on chips buying them online.. I dunno. I miss the 90s. BAD.

[@user-nd8zh3ir7v]

wow thats alot of work, you make it look easy!

[@_derSammler]

I think the white stuff is just limescale. The IC legs damaged by the "cap juice" are a perfect place for that to form, as the metal of the legs has gotten porous, so water can stay there and leave limescale behind when slowly drying.

[@robertclark8351]

You could wash the board in a solution of baking soda dissolved in water, after the white vinegar (acid) wash to neutralize the caustic goo left behind by the leaked electrolytic capacitor electrolyte. Maybe we could ask NurdRage to check that de-Gauss style of closer-to-neutral (and therefore not corrosive) sequence back to neutral is likely to work.

[@jonathanwhiteside6092]

I had to smile to see you using the exact same solder wick as me :) Chemtronics wick is da bomb.

[@jeromethiel4323]

"Things always look better when they are wet." Holy innuendo, batman! ^-^ You had me snorting out loud at that comment.

[@envoycdx]

Glad I am not the only one! 😆😁

[@ToTheGAMES]

A dirty mind is a joy forever

[@gcolombelli]

I'm no soldering expert by a long shot, but if you're worried about dropping solder blobs in sockets, it may be a good idea to avoid using the iron tip to carry molten solder. A friend of mine told me a very convenient way to solder SMD components is to put a tiny bit of solder on one of the pads, then position the component with tweezers, then come back later with the solder to add more as needed and to solder the other pins.

[@johnpetruna8888]

Adrian, have you considered switching the bench overhead camera to manual focus and focusing on the surface of the bench? This would keep the camera from racking focus to the back of your hand.

[@more.power.]

Thank you Adrian

[@cheapasstech]

Had to replace 22uF 25v ones on an amplifier main board … all leaky - 23 units… wiggled them off too

[@mgw1181]

SWIM is Sander-Wozniak Integrated Machine. Wendell Sander, the designer of the Apple III did the work on the IWM and the SWIM. It seems like he decided to add his name to the latter.

[@Darxide23]

I think you'd really benefit from a set of tweezer-tips for your soldering iron. They make component removal a breeze.

[@leosmith848]

Neat job.

[@hit-757]

If I may give you one advice, use flux on pcb while using copper wick. It will soak with tin much faster and easier.

[@Steven_VE9SY]

Never tried it on a circuit board for Cap residue, but putting baking soda on the board and then adding vinegar should help with it. Not to mention the Cap goo, it should get rig of the corrosion on the chips. I've been using this method to remove corrosion for decades.

[@AmigaofRochester]

I personally wouldn't use ceramic, they like to short and are really not designed to be hand soldered (technically speaking). I also would wash the board with soap and water if possible. I will almost always use electrolytic caps for reworks, but if someone has their heart set on something else I will use that.

[@andrewclegg9501]

Voltage coefficient of class ii and iii mlcc caps is also dependent on physical size, i would think yours are fine

[@Peter_S_]

The guy who added the MFM circuitry to the IWM has the last name Sander, thus SWIM for Sander-Wozniak Integrated Machine. After Apple, he and his brother were selling a bolt-on adapter which attached to the IWM port and added 1.44 support to older machines. Inside his adapter was a SWIM, a 6502, an SRAM, and an EPROM attached to a male and a female DB-19 connector.

[@jdenslinger]

I've been watching for... well, since lockdowns. #Inspiring! (I probably should have opened with the lead oxides / white salts comment, oh well) Egrets are a bird, you're correct. I get to see them from my back patio often. I like Deoxit, but I also like to use CRC QD Electronics cleaner... Conisderably less expensive, and works great for cleaning up PCBs - components, the surface, and exposed metals. Works well on "surface rust" on the steel bits too (which reminds me, a #2 pencil eraser works great for that as well!) 99% IPA is probably a bit strong for what you're doing. Try 70% IPA - it's worked well for me. It might take an extra minute to dry compared to 99%. I mostly only use IPA as a drying agent though, especially if I've gotten water or vinegar under components. White distilled vinegar is great for washing away the electrolytes from cap pukes. The acids in the vinegar nuetralize the bases in the electrolytes, and re-liquifies the acids from the electrolytes, to flush it all away. The "salts" that form after things are dry, I'm thinking are actually lead oxide. The lead will leech out and form oxides when the solder containing it is soaked in acids. As I'm writing this, I'm watching you poking at ICs talking about white salts... I may be wrong. It would be interesting to see if that stuff is indeed lead. Maybe you can find a lead test and do that on a video? Also, it's such a small amount, don't panic about lead poisoning... Our parents live(d) to be ripe and old... and they grew up with lead in their snackfoods... >_>

[@erickvond6825]

Honestly I know it sounds crazy but I've put boards with leaky caps on them in the dishwasher. They come out really clean especially when you use a rinse agent. This works for old keyboards too though I wouldn't suggest it for membrane keyboards as they tend to retain some of the soapy water between the contact points. It doesn't seem to hurt mechanical switches though.

[@fattomandeibu]

Not sure how good vinegar is good for electronics, but I can certainly tell you from experience it is the best thing for bringing the sheen back to corroded old coins.

[@bathesheba111]

As we say in the UK you make it .look “Easy peasy lemon squeezy” ! Pun intended…

[@quakesin1982]

I think I liked the "Sassy Recap" more but I still enjoyed this one too, always fun to watch thanks!

[@suvetar]

Don't know if this tip is helpful for anyone else but as per usual whilst watching these videos, I often look up random part datasheets, especially for chips I don't recognise, such as the m341S "Egret" which turns out to be the ADB/I2C controller, with 2 8-bit GPIO and 1 4-Bit, looks like it could possibly be useful in other places ... Anyhoo, digging deeper led me to the MAME source code, and what surprised me is that there are C++ "models" of many chips in there ... obviously they're simulations but it occurred to me that if one gets stuck, then you might at least find out what it's *supposed" to do, if not how it actually does so! Hope this helps and thank you as always Adrian!

[@twocvbloke]

I think had they used tantalums back when that board was new, they would have used the wet kind, which would have been the short-circuit specials, which apparently contain sulphuric acid, which is nice... :P

[@edmaster3147]

But the tantalums have advantages and use. They are quite awesome and very quick, able to filter high frequencies. Very usefull in computers actually.

[@Jah_Rastafari_ORIG]

I keep my solder wick spools over a pen or pencil in a coffee cup on the bench. Always there when I need it....

[@philallen9650]

You could get some Ph paper and test the residue, then use the appropriate opposite chemical to neutralise.

[@mikebarushok5361]

One super cheap way to test for acidity is to make either some very strong tea, or moisten the area and drop a little instant tea onto it. Tea loses it's color with low pH. Another way for us cheapskates is to take some petals from any number of common flowers and use them like litmus paper. For Rose of Sharon flower petals here's an approximate scale (low pH is acidic, 7 is neutral, and high pH is basic): Dark pink: pH 2 Pink: pH 3 to pH 4 Pale pink: pH 5 Lavender: pH 6 Gray: pH 7 or pH 8 Dark gray: pH 9 Brown: pH 10 or pH 11 Green: pH 12

[@user-zm4oy6mf5z]

Electrolytics by smell: Stale water or burnt plastic. GBL. Use water. Fishy: DMF. Use water. DMF is used in paint strippers. Causes plastic swelling. Slight ammonia smell: DMA. Use water or perhaps alcohol These comprise the liquid electrolytes. MgO2 is also used.

[@_SR375_]

I would also cover the other connecters with tape as well, were the ribbon cables attach

[@tss_retro_reboot]

Hi Adrian, was wondering if you can tell me where to get the caps and which ones I need. I have a classic and classic II also that both need to be recapped. Actually have many old Mac’s that need it too so just need to figure out where to get them! Thanks!

[@minty_Joe]

I believe the 2 main values are 10 microfarads and 47 microfarads. I'd say the working voltage is 16 on the 47s and 25 on the 10s, but you can go higher on the DC voltages.

[@godzil42]

The egret chip is the chip providing ADB, and it seems some bits of PRAM and related on this generation of 68k macintosh. It is also used on other LC machines at least

[@piconano]

Have you tried ultrasonic cleaners? Having one with citric acid solution would be my first tool, if I was fixing so many boards as you do.

[@FluffyTheGryphon]

I always use Chem Wick with a bit of flux. Makes the pads look brand new.

[@starsundsternchen802]

When does a video come about the GDR computer KC85 you received as a donation some time ago?

[@bkims]

So, I've used a cleaning solution called master stages clean 2020 with a heated sonic cleaner on PCBs in the past. It works quite well though its not strictly intended for it. I haven't tried it specifically for cleaning verdigris corrosion but its dealt with just about every other kind of corrosion I've thrown at it. It may work quite well for these old corroded boards. Especially getting under the legs of SMD ICs.

[@UpLateGeek]

Oh yeah, I hate it when the tweezers get sticky from the flux! I recapped all my old macs with MLCC caps, but I never knew about how they need to be derated based on the voltage. They all worked, but now I'm wondering whether I should re-recap them. Or at least stack another cap on top.

[@awilliams1701]

I've actually watched krisfix germany do repairs on modern video cards and he has schematics where you can click on a trace and it shows everything. So it's not just amigas. If you click on a chip it shows the purpose of every trace. It's really nifty.

[@infineon222]

I wish I could see how to repair a ripped pad because that happened to the rear input board on my 1702 monitor :(

[@Wikcentral]

Ray does a complete twist until the legs snap when he removes them. But wiggle works as well. As far as PCB cleaning, Louis at one time recommended Branson EC which I do use for cleaning gunk and flux in my ultrasonic. I would be interested in how it does with just soaking on a board with leak damage.

[@An_Onion]

I used to use the MG Chemicals stuff for years until I used some Chem Wik that someone left behind. Damn that stuff is amazing. It's all I buy, now!

[@nekosarantango865]

A friend of mine used plumbers flux after ran out of electronics stuff, in his mind flux is flux, till next day when every single pin he used it on was burned off...

[@Makeshift_Mulder]

45 Dislikes? Huh? Who are these 45 maniacs?.. What do they want?.. _whoooo arrrrree yoooouuu??_

[@nepas3628]

Adrian, you should wait 10-15 mins before starting to rub, you've to give time to the vinagre to do it's magic, after rubbing wait another 10 mins before giving the board a good wash (distilled water if possible) and finally use IPA to remove any residue of water and gunk.

[@nilz23]

When I use alcohol even for cleaning flux off I like to tilt the board so a lot of it runs while I clean off before it can evaporate. I think it carries anything in it or dissolved in it off the board that way.

[@elfenmagix8173]

Oh Adrian... First off, the Classic II is in Stereo, you can only hear in Mono with its single speaker, but put in stereo headphones and you will hear it in stereo. Also, Apple, with the 68K Macs and many of the PPC Mac, used a Sony chip for its sound generation, and only uses one chip as that chip is in stereo. So look for a chip that has "SONY" on it. Also, the LCs are in Stereo, then the Classic II came from the LC II. (NoteL LC II & Classic II both have '030 CPU with the 10mb RAM limit while the LC only had the '020 CPU like the Mac II.) Looks like you did a great job recapping the board. As for Cap, I prefer the Tantalum Caps in the Black Case (Non-Polarized if possible but if not Polarized work just as well, just remember that the stripe on the Tantalum caps goes to the + side.) Those Black Tantalum caps on a board with back chips - looks so good! Because the Classic II has no FPU, it is very much slower that a SE/30. Besides some app and games, you need the FPU for Postscript and True Type Fonts, or drawing to the screen will be much slower I know the boys in the 68KMLA forum mad their own FPU board for the Classic II, and there is a Git Hub repository for it so you can make a couple boards from PCBWay. You need to go in there and ask around. Puttin a FPU into a Classic II (and any of the LCs) will improve it by a lot! Lets see what happens on the weekend. Take care.

[@Kirill_Maker]

which cap nominals "up to" can be replaced by ceramics?

[@williamvonroenn8063]

You are correct saying it's a salt. When you have a base (electrolyte) and an acid (vinegar) you end up with water and a salt. Chemistry my good fellow. 😂

[@xredhead7135x]

I like to print the board pictures and then mark up by hand before removing components. Or use a pdf markup editor and keep on a side screen to repopulate the board.

[@jeppeuhd]

Try the vinegar on a board without damage - i think it will foam there too - i think the bubbles are “just” small bubbles created by the brush going over the pins

[@RufoSanchez]

I thought that at first as well - but when he goes over the same area again, there are almost no bubbles... which at least gives the impression that _something_ happened the first time he brushed there. I'm less of an expert in this than Adrian or most of the people here though so that may not mean anything either, just something I observed :)

[@stamasd8500]

The foaming is likely not a sign of any chemical reaction. It is likely that the leaked electrolyte contains a wetting agent, aka detergent - and that gets dissolved in the vinegar and with mechanical scrubbing it generates the bubbles that persist a little longer than they would in the absence of the detergent.

[@user-nw2kn8dk7z]

Because of how tight the motherboard is in some places, I couldn't avoid melting some of the plastic pieces on my classic II motherboard. I used aluminum foil to cover the pieces, but it didn't really stay on that well. After recapping my logic board, I can't get sound out of the speakers. I think I fried the 47 microfarad cap on the top left of the board. The reason why I think this, is when I short its legs the speaker makes a crackle sound on startup, vs no sound when I don't short the legs. My thoughts are that this capacitor is a filter capacitor for the sound, and that it's fried from my botched solder job from this specific capacitor. Any thoughts on what I should do? I am really confident that I messed up this capacitor and should replace it, but this was my first repair of any logic board ever, and I just want to be sure.

[@kuro68000]

Ultrasonic cleaning really is the way to go. No amount of scrubbing will get it as clean as ultrasonic cleaning. No more fish smell. The only problem is you need a big one for motherboards.

[@preferredimage]

Well i gave it a go and got a cap kit for my mac colour classic. recapping went fine and I get a stable picture. I think my scsi drive is dead or dying as it sounds like a leaf blower but my main issue is it boots to a mouse pointer maybe 1 in 40 goes. otherwise I get the boot chime, then the chimes of death.... Anyone got any ideas as to causes of that?

[@TonyHamlyn]

You said the cheap braided wick sucks, but actually it doesn't suck (the solder up into its braided mesh) LOL.

[@elmestguzman3038]

Vinegar is right thing to use. The capacitor leaks a base type chemical the vinegar is an acid they will neutralize each other. You still have to clean the board after to get whatever residue is left, but the corrosion effect will stop.

[@pieroc91]

I've had some PCB that became somewhat conductive due to capacitor or ni-cad leakage and caused all sorts of weird behavior. Vinegar helped me in cases like that.

[@stevesretroloft]

It looks very much like my Classic II motherboard did. It's not working again, but I think the Analogue board is one its way out so need to recap that (Electrolytic and Rifa caps)

[@krbruner]

Adrian, I contacted you earlier about sending you something, that would help in board repair, from Amazon, however, they required a phone number, which I was not about to ask you for, so I dropped the idea. I will however tell you what it was, as a suggestion, for a possible item to pick up, or to throw on to a wish list. It is a Pentel Clic Eraser Pro. It has a metal body, which keeps the eraser firm, which the eraser compound is rather hard and mildly abrasive. The tip is a long rectangle, which can be used to clean something either wide or narrow. I used to use then to clean boards, and in former life, I used them to clean the charger port on Nextel phones that I used to rebuild 90+ of every day. They are also not effected by IPA, in case you wanted to add some to assist in the cleaning.

[@only257]

Good

[@mattdavis8899]

If concerned about an alkaline product, such as leavings from a battery or capacitor, vinegar (which itself is diluted acetic acid) is a great at-home solution for neutralization. Regular white vinegar is usually 3-5% acetic acid and should neutralize things just fine.

[@bobothn]

If the movie Fight Club taught me anything (Besides not talking about Fight Club) its that vinegar is a good acid for neutralizing a base.

[@Electronics-Rocks]

Good quality vinegar works fine neutralise the alkaline as long as a good wash. I did use an industrial acid diluted but the UK chemist no longer supplies chemicals. I know eBay but going back to vinegar works. Get rid of all green as it comes back. You complained about the alcohol but back in the 80's I used trichloroethane which used to get me as high as a kite!

[@vojtara]

SWIM stands for Sander-Wozniak Integrated Machine and is different to IWM because it can handle 1.44MB floppies. With IWM you are stuck with 400/800k.

[@EnigPartyhaus]

Me and a m8 are currently investigating how easily a SE/30 board can be put into a CII and so far all signs are pointing to just needing to pull -5V from somewhere on the analog/PSU board and making an adapter to swap two pins and pull the sound from the board's speaker connector and then the usual dremeling of the rear of the case, the CII really is just a SE/30 rammed onto the same gimped bus as the LC III it seems

[@gabrielleeliseo6062]

Acetic acid in vinegar would probably be perfectly fine. It has the benefit of being mildly acidic, so it works well as a general detergent.

[@blazini]

Curios why you're replacing aluminum caps with ceramics when you're aware of the difference in behavior. No need to guess about capacitance roll off if you just use aluminum replacements. I don't think I've ever used above 10uf MLC, as aluminum performs better anyway. Newer caps from say Wurth are cheap enough and don't have leaking issues so it just seems counter intuitive to use ceramic caps as replacements

[@soverysleepy]

you can reclaim the caps if the machine is dead they are still new

[@senilyDeluxe]

Now here's a really stupid idea (business/manufacturing wise): Let's make capacitors (and lithium batterys) with a little compartment for vinegar, so that when the seal fails and the cap / battery leaks, its chemicals instantly neutralize themselves! That would make'em bigger and much more expensive!

[@kencreten7308]

"Thanks for that, Apple!" heheh

[@Cherijo78]

I still have a bit of my vintage 1990s Radio Shack wick sitting around because I can't ditch my childhood so readily...! Most of the time I use MG Superwick because it's a bit cheaper than the Chemtronics Chem-Wik. I haven't bought any in awhile, and I just looked up the price and almost snorted my milk everywhere. That 50' length is up to over $38 now on DigiKey. Yikes.

[@minty_Joe]

And the Radio Shack solder wick is garbage. The last roll I had of Shack branded wick left a burnt copper residue all over the area I was cleaning up. It didn't even absorb any used solder. What a ripoff!

[@TheTkiller9999]

the chemical that the Capacitors leak is a strong Base material, the Vinager is a weak Acid.... they cancel each other out... and Vinegar is easy to remove

[@MOS6582]

Yes hello please send me three of those wide auxiliary CRTs. They make my heart leap with joy and it is necessary that I possess some. Price is not a factor. Thankyou. /jk There are so many cool things about your machine but the coolest thing is that it’s been preserved and is alive for people to experience. It must be very satisfying every time it boots👍

[@larrysmall3521]

Try using Chem Wipes with your toothbrush and IPA. Put the Chem Wipe over the residue and use a toothbrush soaked in IPA to scrub the Chem Wipe and the residue. The wet Chem Wipe will absorb the chemicals from the board.

[@maltronik]

The wiggles method remind me of my dentist.. 😁

[@PicaDelphon]

AAnd I have a Special CAP Iron tip I made from a Nice Nickle Bolt....

[@panopolis8051]

NO EGRETS!

[@PicaDelphon]

Some Cap's Are good for Smoothing DC w/ Power Surge w/AMP's, and Some are just for Filters wo/ Surge in Amp's.. But if Power is Good thru the Main PCB and Spreed the AMP's then Filter is Good and No more Juice on the PCB's and IC noming..