hpr-knowledge-base/hpr_transcripts/hpr2314.txt

Episode: 2314
Title: HPR2314: Bad Caps
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2314/hpr2314.mp3
Transcribed: 2025-10-19 01:12:33

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This is HPR episode 2,314 entitled Bad Caps.
It is hosted by Enneville and in about 26 minutes long, and car in an explicit flag.
The summary is Enneville talking about repainting a computer motherboard.
This episode of HPR is brought to you by an Honesthost.com.
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Hello, this is NY Bill, and I'm back to do another HPR, and it does involve electronics again.
And it does involve capacitors, which I think someone asked about.
This is what happened, and this is what's in front of me.
I was at the lug last month, so this was three weeks and a few days ago, now since I'm talking to you.
My buddy Marcus walks in, and he's got his whole entire gaming rig with him.
So it's a big honking, super cool computer with big fans on it.
It's not just your average PC by off the shelf.
He built this as a gaming rig, and I'm just wondering why he's walking into the lug.
When we all have little laptops, he's bringing his whole entire computer in.
Everyone's making jokes about bringing the rest of the computer room in with you and stuff like that.
But anyways, he sits down next to me, and I said, why do you have your whole entire gaming rig with you?
And he goes, I broke it.
So, how do you break your gaming rig?
And he starts taking it apart.
I go, well, why are you going to take it apart?
Are we going to help you fix it?
And he goes, no, I think I'm done with this one.
The motherboard shot, and I'm just going to take it apart and maybe sell the parts on eBay or whatever,
and it's time to build the new rig.
And I said, how did you break your computer?
And he said he was overclocking it, and he said he was overclocking the Core i5 like past.
You know, he's getting up in an area where he shouldn't have been clocking that fast.
And he started hearing pops, like a very loud pop, and then he heard another very loud pop.
Now, anybody that knows capacitors knows what's going on there.
Well, he could be frying any component on here, but a cap, and especially these caps,
I'm going to talk about in a minute.
These ones will pop, like popcorn.
Other caps will do other things.
I'll tell you about that.
So, I said, don't throw out the motherboard.
Give it to me, and let me just see, I might have the capacitor at home.
Let me just see if I can replace it, and if I can fix it, we can, you know,
give it to someone or build another rig, or, you know, use it as a second computer.
So, here it is in front of me.
Take a picture.
I don't need even, this isn't my computer, so I don't even know what board this is.
AS ROC.
XFAST use XFAST gram, XFAST LAN.
I guess everything is XFAST.
This is a super fast.
No, AS ROC, THX True Studio, ATI, I have no idea what brand this is.
Anyways, I'll take a picture of it, and if anybody wants to tell me what it is,
there's extreme all over it, so, you know, must be super extreme.
Anyways, I'm looking at the bad caps right now.
It's very easy to see them everywhere, all over this board, or gold caps.
They're polymer caps.
Well, I think these are nichikon, let me get my magnifying glass, gold caps by nichikon.
Anyways, that's a respected maker of caps, I'm not seeing, I'm just going to go with
that.
I might have to Google it later, but, anyways, there's gold capacitors all over the board,
they look like a can.
Usually what people would think of when they see a can, a capacitor is an electro-litic
capacitor.
I can talk about some of the differences in a minute.
These are solid polymers, so this is fairly new, I guess.
I'm starting to see them more and more, actually, I just took it out of the bag, and I can
smell the burned smell of the liquid smoke, or the magic smoke getting out.
This board, you can smell the burning on it.
Now everywhere on this board are the gold cap, gold cap, gold cap, gold cap, you get
up near the CPU, and there you just see two charred black things that look like a coil
of paper that someone held a match underneath, and just started charring the paper.
These are the two caps that were bad, there's no doubt about it.
He showed me, he didn't have the gold cans that popped off of these caps, but he showed
me a picture of them on his phone, and I don't know if it was like the explosion of them
coming off, popping off the top of the cap, or they popped off so hard, like a bullet
that they hit the other side of the case, because they were dented on the top.
These things popped pretty good.
I told him, just don't throw out the board, I'll take it home.
Let me see if I have the capacitor to put in here.
I came home and I did not have the capacitor.
I don't have any solid capacitors, solid polymers.
I have electrolytics, everybody's got, well, I don't know about everybody, but I have
ceramics.
I have like the old school through-hole stuff.
These are still through-hole, but they're more of a surface mount type thing, like a pick
and place machine would do.
So, the electrolytic is probably what most people are familiar with, the little can type
of capacitor.
They're usually black, sometimes they're blue, I suppose they could be any color, but
black and blue are the most I see.
They are polarized, you'll see the voltage wants to go in one way and out the other.
Most of them at the top have a little slit, either a one slit or a crosshair slit.
That is for when they blow up.
Electrolytics have essentially a wrap, well, capacitors in general, it's two plates.
There's two plates of metal, and nothing's touching in between them, but not voltages flowing.
A magnetic field is being generated, and negatives can pile up on one side, and positives can
pile up on the other side in this field, and then they can flow back out.
So what a capacitor is basically doing, it's like a battery, it's a storage of potential
energy used, and when you're bored or whatever your powering pulls down your energy below
your norm, let's just pick 10 volts.
If whatever your powering up is running 10 volts, everything's smooth, everything's smooth,
and your motor or your computer or whatever you're going to run, wants to drag things down
to eight volts.
Your capacitors in there are just going to push some more and smooth things back out.
If you look at a scope real close, you might see like a little ripple, but it will help
get things back up to that 10 volts.
So they're just sitting there kind of regulating, and they're filtering.
And in power supplies, you see large, quite large capacitors, because those are going to
power the whole system.
I'm looking over on my bench here, and I got an analog scope, and I got a digital scope,
and these all have power supply units in them.
So those would have some pretty big caps in them, because they need to service fairly
like low frequency dips, if you will, but for the whole entire machine, the whole entire
system.
So they're doing like large, it's hard to explain, unless you go into like a lot more
detail than I am, but I'm keeping it light.
These capacitors, the ones that blew up on Marcus here, these are decoupling caps.
So when power leaves the power supply, we'll use a computer in this case, because that's
what this is.
The power supply has its own capacitors in there, and they're helping regulate the overall
power coming out of that power supply.
There's probably, you know, there's five volt rails, it could be 12 volt rails, whatever,
whatever, what have you, anyway, they want to split it up, but they have larger capacitors
in there, helping to send the proper amount of power out of the power supply, and onto
this board.
Once you get to the board though, the power is going through all these little tiny traces.
These could be like seven layer boards these days, so powers, it looks like it might be
going like five inches, it could be sneaking all through the board, and by the time you
get up to where it's actually entering a chip, you got like eight or ten or twelve inches
of trace there, that's going to add inductance, it's going to add like resistance and like
capacitance of its own.
So what happens is something like a chip, like this CPU right here, it's going to want
to switch it very high frequencies, it's going to want to grab power very quickly, switching,
we're talking gigahertz here.
It's going to switch crazy fast, but power has to get out of the power supply, snake all
the way through this board, get into the chip, power whatever, switching that chip wants
to do, and then come all the way back out and get all the way back to the power supply.
If you didn't have these caps that I'm going to talk about here, you would have one really
weird system, because it would just be sluggish and slow, and there would be no timing
to it.
These are decoupling caps.
So what these are, they sit very close, almost every chip I'm looking at here, all these
surface mount chips, all surrounding around them, they have little tiny surface mount decoupling
caps.
What decoupling caps do is the power comes all the way out of the power supply, snakes all
the way through this board, enters the chip, does whatever it's going to do in there,
and you don't want it to have all that lazy way back to the power supply, so you stick
a capacitor in there and just let it go right back to ground, right there, right outside
the chip, and again, it's hard to explain, but I hope that just gave you a general idea
so you can look into it further if you want.
There's Wikipedia's and there's YouTube's and there's everywhere.
I'm just basically talking about the repair here, so my next problem was, as I said, I did
not have solid polymer, oh, that's what I was saying, the electronics, the ceramics,
those little round disks, those are just really two plates of metal separated by a dielectric
where you got the positive and the negative piling up on the two plates and it can leave.
An electrolytic is like a coil of plates where two plates go around, but they're not touching
each other, so they spin, spin, spin around, and they're sitting in kind of like a pasty,
it's liquidish, I have no idea, I've never taken one apart, but if you heat one of these
up, you start boiling off that dielectric in there and that was what would pop out
the top of the slit or the two X's that you see creased in the top of the electrolytic.
If you're ever working on something and you see that crease and it's bulging, it's doming
up, that capacitor is ready to fail and it's probably in the process of failing and it
may be what's going on bad with the piece of equipment you're looking at, I can think
of one example is a monitor I had once that every time I would turn it on for like the
first 10 minutes, it would look all psychedelic, all the colors would just like, they were the
wrong colors and they would ghost off each other and I had to let the thing warm up and
slowly the screen would just start working and after about 10 minutes it would stabilize,
what that was was the capacitors that were in there that were handing the frequency of
the refresh rate were failing, so someone were going slower than they should be, so they
were all probably going slower and they should be, but they're varying degrees, so when
the trace was trying to be drawn on the LCD colors were just getting in the wrong spots,
it actually looked neat but it wasn't functional, so I opened that monitor up and you could
see almost every single large cap in there, electrolytic cap at the top was domed out,
it was ready to vent out which is when you boil off that bielectric in there and it comes
out the vents in two slits, so if you're ever servicing a piece of equipment and you open
up and you see electrolytic capacitors in there and you see a dome on the top or you see
one split right open, there's your bad cap right there, so just go ahead and replace
that and as long as you're in there these are so cheap, find out every other cap of that
value from that manufacturer on that board and just while you got the thing apart just
replaced all six or all eight or however many are there because they probably came out
of the same run, they could have been a bad run of cap or not so great a vendor and
just while you got the thing open they're cheap enough to do all the caps of that value
from that vendor, the one that went that on this board is a solid polymer, I'm not even
really too familiar with these, I didn't have any though, I do now you can hear I'm like
rumbling through some, so what I did is looked up, we did this while we were at the
log being my buddy he goes by rusty one, we were trying to dig into what these caps were
and you got to read like a little code on them because they don't say like such a such
microfarad, there's a little code where the first two digits are the first two numbers
of the microfarads and the third digit was how many zeros are there, so there's just
a little code and we looked in, we found out, these are 820 microfarad caps, I get home,
I realize I don't have the liquid polymers so I need to order them, so I've done some
other HPRs on like where to acquire electronics parts, I remember mentioning Digi-Key and
Mauser and some others and I could find them on there and I just need two of these things
and they were like, I don't even know what they were but let's say 30 cents each, so
I need 60 cents worth of parts and it was going to be like $7 to ship them to me, what
I like to do is go to Banggood, that's B-A-N-G-G-O-O-D, this is a Chinese, I wouldn't call
it a retailer, I'm not sure what to call this, it's kind of like an Amazon third party,
so Banggood is like the forward-facing store and then other vendors are behind it selling
things to the rest of the world and usually the stuff is really cheap and that can
go, that can bite you both ways, it can be cheap price-wise and it can be cheaply made,
so be careful there but when you get into electronic components they are so inexpensive
if you need 500 ohm resistors and you look on Banggood you can find a package of 1,100
very of all different size resistors for like $5 and it's free shipping, I don't know,
we still don't know in the lug how it's free shipping, I don't know how they do it but there's
we have a joke in our lug IRC, if anybody ever came into our lugs IRC there's so many inside jokes
it would take him a while to catch up, one of the jokes is you know where are the donkeys or
how are the donkeys, because way back when we were looking at Banggood and we were wondering how
they can sell something that's $5 and so send it all the way to America for free shipping,
we joked around that they must be using donkeys, it's like free labor, so sometimes in the IRC
we'll be saying you know like Rusty Wann asked me about these capacitors and he goes how are
the donkeys bill, so he was asking are they there yet and they weren't and I said they're still swimming,
so that was the joke you know they're swimming in the ocean they're bringing the, anyways they're
here now and while I was in there looking for capacitors I found a package of electrolytics,
I found a package of mylar caps, these look like if anybody knows chicklit gum these look like
they come in different colors, I usually see red or green, they look like chicklets with two wires
coming out of it, I didn't have any mylar caps so I put that in the basket, so these are little kits,
these are the solid polymers that I got are 10 values, 90 pieces,
yeah it doesn't say on top of it but it's similar all around, I'll take a picture of these,
so on the left is the solid polymers, well first I'll take a picture of these,
there's bad capacitors on the boards, you know what I'm talking about here, so they are in the
first picture of the show notes, you'll see gold cap gold cap gold cap and it's going to be pretty
obvious, these two burn charred things that are unfurling, this second picture here is on the left,
is the package of the solid polymers in the middle are the mylar caps, they look like chicklit gum
and on the, did I do that wrong? No, left is the solid polymers, middle is the mylar and right
is some electrolytics, I have tons of electrolytics but these things are so cheap, these little kits,
I forget what they were but it's like five bucks each or something like that, so for 15 bucks,
I got all these caps, I'm going to use the two I need and stick the rest in my ever-growing parts
bin but you can never have too many parts, right? So here they are, two 820 microfarad
solid polymer capacitors and the next step is to fire up the soldering gun,
suck these two bad ones out and put the good ones in, so I'll do that now,
hello, I'm back, it probably seems like just a second to you but this was actually weeks
in between the last time I recorded and now I'm not even really sure what I said back then,
I know kind of where I left off, I got to change these two caps which I said might be decoupling caps
but as I kept looking at it, they might be supplying power to whatever is underneath these
extreme heat sinks here, anyways, then I thought in the meantime just to mention a few other things,
of course you got ceramic caps, you got electrolytic caps, you got these polymer caps which I found
out are nichicon, you have open air core caps which this is just in general in case you want to
keep researching caps, like an open air core would be in an old style radio when you're
changing the tuning knob, you actually are moving fins, kind of like pie shaped, well, pie shaped, no,
a pie if it had one quarter missing out of it and as you move these fins, you're increasing or
decreasing the amount of metal that is in between each other, it's very hard to describe, I'm also
talking over this buzzing noise you can probably hear and there's more of the story right there,
so the reason this took so long is I researched the caps, I found out they are nichicon, I found
replacements for them on digike and I ordered them so I had to wait for those to come in,
I got four of them just in case then I went to put them in, I could not get this soldered a mill,
I haven't done much work on like computer boards, the solder would not melt with my Haco 80,
what is this, an 8080, FX 888D which is a really nice unit for like 90 bucks, you can get this,
this is really excellent digital, it's hard to talk over this noise that I'm going to tell you
about in a minute, yeah the FX 888D is a really nice digital soldering station if you're looking
to pick one up, so I had a whole bunch of trouble desodering the old caps, so what I thought of is
I've always wanted one of these but I never really did, I never pulled the trigger on it, I always
just used my Haco and one of these vacuum pumps, I can do it now, it just looks like a big syringe,
you cock it, you melt something and you pull it out, but what I did next was got an actual desodering
station, so this one you can hear now, oh the other noise just shut off, I'll tell you what that
noise is in a minute, so I got a Haco FR 300, this is a desodering gun, so what it is is the pen
heats up and in the middle is a hole and you put it over the component and as I'm going to do now
you pull the trigger and it sucks the solder, sucks the solder out automatically, I wait for this
to come in the mail, I go back to the board, I try and get these caps off, it won't touch it,
I cannot get this solder to melt, so I start looking online, you know what's going on, what's going on,
it turns out that the solder they're using on modern motherboards and so on, probably you know
video cars, all those type of components, as a higher melting temperature and there's no lead,
it's just all tin and from everything I read in order to try and work on equipment like this,
you really need a hot air rework station, so that's the noise you just heard in the background,
that is a, I don't know how to say this, a yoi, it's a, I found it on Amazon, it's a rework station,
a yoi 852a plus plus pro, it sounds like, yeah it's perfect for an extreme board, a plus plus pro,
anyways, all hot air gun is, it's going to have a heating element in the handle,
you heat it up to whatever temperature you want and then it will blow air through, finally I got
this solder to move, loosen up, then I did suck it off with my, with the suck, the, I don't know,
vacuum, vacuum gun, whatever we're going to call that, and then it's a pretty simple from there,
you got clean holes on the board, push the new caps in, make sure they're in the right direction,
electrolytics want to go one way or the other, and we got a little solder paste, comes in a syringe,
stuck that on there, got the heating gun going again, one thing I did find out about the heat gun is
sometimes you're blowing the hot air there and you can see that the solder is starting to move,
sometimes if you just take the tip of the hot air pencil and just touch it to the solder,
kind of like a soldering pencil, it'll just get that final flow to go and then you get the air going,
and I know I'm going to get yelled at by Ken, because this could have been three episodes,
maybe it will, I might do a review on both the hako solder, the vacuum thing, I don't have a
term for any of these and the hot air rework station, but that's, geez, I don't know how to sum this up,
because I don't remember what I said in the first part, this may be totally disjointed, or you know,
just roll with it, it was a repair on a motherboard, so I'll see Marcus at the lug next meeting,
and I will give him this back, and he's going to have two capacitors in your place that are not
gold like the others, because the gold must be extreme, I'm sure these, I'm sure these Nichicon caps,
but they just have a gold cover on it, how can you change the polymer and make it extreme?
But anyways, there we go, hopefully a successful repair, I think it is,
I suppose I could test it, but I don't feel like pulling a computer apart right now,
I'll give it back to him, and he can let me know if it works, and I could let you know in a
follow-up episode. Okay, so if anybody wants to contact me, I'm NY Bill at Gunmunkinet.net
for email, and oh yeah, I usually give my status net here, I'm going to be working on my two VPSI,
VPSs, I have a digital ocean and a linoid, I'm going to try and merge the two together, this could be
another episode, and I want to try and consolidate things, so the digital ocean is going to be going
down at some point, and that is hosting my status net instance, which is terribly out-of-date anyways,
and it doesn't have HTTPS, so in the meantime, what pops up is this mastodon thing, which it seems
like I haven't looked in this too far, but maybe somebody could do an episode on this, you know,
how did this whole mastodon thing come about, and just bring us up to speed on it.
It's a, supposedly, it's, well, it's GNU social, but they kind of revamped the user interface,
and I found out that SDF, which I've done an episode on in the past, SDF has an instance of mastodon,
so I signed up for that, and I just started using it a bit for like the last two weeks, and then
just slowly, you know, start subbing some of the guys that I talked to, and just seeing how I like it,
and so far I'm getting along with it, so I think I'm going to use this as a stopgap
in the meantime for when digital ocean goes down, and I'm moving the database back to linoid,
where I'm going to consolidate everything on a linoid, so if anybody's following me on status net,
and I seem to disappear, or I'm not talking so much, I'm over on this SDF's mastodon.
Let me get the URL. So it's httpsmastodon.sdf.org slash at nybill, and they finally let me use the
two capital, the, so, New York, so ny, and then small b-i-l-l, so if you want to sub me over there,
I've been chitchatting over there, or I am in IRCs, and I think that's it. I wonder how this edit
is going to go together, because I don't remember what I said three weeks ago. Okay, I'll talk to you guys later.
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