Fixing another two Gen 2 KRK Rokit 6 near field monitor speakers with the black gunk of death and failed capacitors.
How wide spread is this problem?
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Hi. In a previous video, we took a look at this Krk Systems rotate six off Rocket Six as some people pointed out, it should be pronounced empowered near-field studio monitor speaker and how we repaired this by scraping off the info now infamous Black Gunk of Death which is a potting compound put on there for good reasons to stop our vibration on the components. but unfortunately in a lot of these, apparently it's like very widespread in the industry. In this particular Gen Two series of rocket speakers, it's a hydroscopic which means it absorbs moisture and it actually becomes conductive.

And it's on the PCB and the components of Shorts amount and in this particular case, it destroyed our poor little tweeter. Um, so link in that video down below and at the end if you haven't seen it. But thank you very much to an anonymous AV blog forum user who donated these to our Row Kit six speakers and they've both failed. So like this is really bad when like, what are the odds of both of your speakers failing? There's a huge problem with these.

Our Gen 2 Rocket speakers now I am led to believe that they have fixed this in the Gen 3 speaker. So these are Gentoos just like the other one here and let's take a look at them apparently. I'm told that one this one here with fault on the top actually has a very similar tweet-tweet ER oscillating issue to the one that we had over here. So I'm not going to power that up with the tweeter actually attached, but this one here apparently has some other fault, so hopefully we'll get like some other fault inside this thing rather than just the hydroscopic, conductive black and gunk of death.

And you can actually see here how these cones are a little bit actually because these were like the same stored together or whatever they had been stored for a couple of years. you can actually see that the cones faded. so maybe that's been getting some Sun some direct Sun or something like that because there is a big color difference between those two there. And of course this one's in great Nik it's a much yeah, it might be a newer unit I'm not sure the exact age, but anyway, let's pair up this one first and see what the problem is and you can also see the difference in the yellow here.

Look this, hardly any yellow left on this one. So yeah, I suspect that there I Don't think that's just like a different you know depth of color in the silkscreen. I Think that's you know, some sort of UV fading or something like that so they may have been stored in under. you know UV lights or Sun or something like that.

and yeah, I think that's I confirmed on the back here because look, yeah, we've got a nice solid yellow on the back. So I don't think that one's seen the UV All right, we'll power this one on and see what we get. There's no hum, no snap, crackle and pop. Okay, it's feeding a signal.

Hang on. Check this out. Watch what happens when I turn it on. Well, full cone excursion.

Yeah, something's up. And listen to this sounds like there's no water at all. Okay, so that is one sick puppy. It looks like the woofers gone and we're basically only getting the high-frequency stuff out of there.
I Know my voices. you know high pitch, but Jesus is ridiculous. Let's crack it open all right. It looks identical to the previous one, but I see some differences down here on the board straight away.

Let me show you this is the board from my previous site repair previous speaker. Check out how these two filter caps here are exactly the same size and diameter whereas this one down here clearly two different diameter caps in there. and the silkscreen actually follows that. so it looks like they're different revision boards.

And also you'll notice that the XLI import board here is blue and the one over here previously is green. And yes, as a lot of people are pointed out, the RCA connector input this big huge walk here is to stop the air escaping through the hole that would otherwise be in the back of the RCA connector there. I Just still think it's just a ridiculous amount of effort to go to to seal up the exa like the RCA connector. But anyway, it's nothing wrong gilding the lily.

It's great. And yes, we do have the black Gunk of Death on this and we'll take a look at that. But the first thing that stood out to me was the Bulge in that cap. These Yukon caps at just one hung low brand caps and that's just failed.

so you're going to replace that. Of course, these two filter caps are going to be for this power amplifier, which is for the woofer. it's the higher powered one. So yes, straight off the bat, you'd get those both those caps out and replace them.

These ones don't look raised at all, but still. if you're going to replace these as a matter of course, you'd probably replace these two as well. And there it is. the hydroscopic black gunk of death.

But oh hello, hello, Is that poor resistor? Aha, is that fried? Well, that was that 2.2 K that we actually replaced last time because the lead was corroded on it. But what the hell is like? This is just unbelievable. This stuff isn't absolute play and it's like every Gen 2 speaker from broke it has to like I Believe all the different sizes, not just the Cinch 6 inch to the 4 and 5. And and the eights are afflicted by the same black gunk of death as well.

And it's just man. horrid. Wow. You should be able to pick up some bargains on eBay though and before people ask.

And it was a popular comment on the previous video is that no, I don't think this is in any way any sort of deliberate planned obsolescence thing by putting this gunk in and they knew it would become conductive. They just like pick the wrong cut potting compound. I Don't know where they got it from, but it's just Murphy came and bit him on the ass. but they don't want to seem to own up to the fact Krk systems don't want own up to the fact that this is actually a problem apparently and that's just ridiculous.
I Mean, come on, you know people, especially technical customers understand that you know happens, someone's got to deal with it. No, you're gonna call. But yeah, there's no way that a company like Krk Systems, who's basically only product is near field reference monitor speakers. that's their whole bread and butter.

They are not gonna deliberately put something in their planned obsolescence in a product that's not a consumer product. It's going after the pro audio market and people expect their monitors to work for a long, long time. There's no way they did this deliberately. That's just BS.

So I don't believe that at all. Let's measure out gunk. Whoa. Oh Gunks Good, No.

Gunks good. Um, this meter goes up to 50. Meg Let's go into the one down here. Ah, this one's not too shabby.

actually. this one, maybe in a drier environment hasn't picked up nearly as much. Ma, ya know? Yeah, there you go. That's actually the worst we've seen that's around the Wolfert No wonder the woofer is not working and probably why I Still not sure if that resistors burnt out, but yeah, anyway, still a problem.

So we've got caps and black gunk. Unbelievable. K-o-k See, since they did so well. design in everything else.

I Mean they're You know these. This company knows what they're doing with all the excellent sealing and stuff that they've got in this thing that you know they're real, the properly designed acoustic enclosures, the drive is everything else, but it doesn't matter. Diddly squat if you screw up some basic electronic stuff like just using quality caps and you know, and no one like proper, like you know, reputable brand potting compound. Because any reputable brand potting compound wouldn't have done this all right.

So I go in there and scrape this off. It gets everywhere by the way, it just flake crumbles off. So yeah, definitely do it in some sort of tray or something like this because it's gonna make a mess. Anyway, let's give it.

The good thing about this board is that it is a single sided board so you don't have to worry about you know, scraping it off or anything like that. You don't have to worry about digging out any tracks. Horrible job. Somebody's got to do it.

Unbelievable. Look at this. and yeah, and we started to corrode some of those links. It's just awful.

This is just so medieval. Now as I said, some of this is not conductive at all. At least what it measures are on a multimeter at, you know, in volt or whatever or to that it's actually measuring. That doesn't mean that it's it's dielectric properties can't change based on the applied voltage because speakers aren't.

You know it can be quite high voltage. there can be, you know, 30, 40, 50 volts inside a speaker system like this and amplify a board like this and that could change the properties and cause it to break down and conduct or something like that. But I'm scraping it off and I'm not seeing any of the liquid so none of that water entrapment that I saw last time. But each one's going to be different depending upon the type of material.
how at the Howard I aged? what sort of, you know, humidity conditions, it was, stored, it, and all that sort of jazz looks like the stuff that's not conductive actually still has a bit of compliance to it and sort of like peels up instead of crumbles off so that stuff is still in reasonable. Nick but you would take it off as a matter. Of course, it's important to sacrifice blood to the repair gods. It's the back of the board for those playing along at home and that 2.2 K resistor in their measures.

Okay, so I probably won't touch that and there's those two support side by side. This is the new one I've gotten. this is the old one. You can see quite substantial differences.

Look in terms of this vertical resistor. here. it's horizontal over here and it's got different caps arranged in different ways well, as are the difference in size of those caps there. But those two caps, even though there are very different footprints, basically the same cap? well, you know, thousand volt, 35 volt rated, and other massive differences.

that 16 pin Op amp down here. 8 pin Op amp over here, a relay on this one. no relay on this one, so presumably no or different power on d Thump protection. So yeah, but they're vastly different designs.

but I just noticed this one over here that I said is the new one is actually an older revision. This is Rev 2.0 It says it in there I won't show you this one is Rev at 3.0 So this is the new one. So they've removed the relay that they had over here and they've gone to this 16 pin Op amp down here instead of the 8 pin job and a few other things different and as well as the two different size caps there. So this is the board from the other speaker that's supposed to have the bigger oscillation issue.

and sure enough, the black gunk there. It's actually very low and look 140 K It's like it's the lowest we've actually seen. It's interesting that that's actually around the power resistor which is presumably going to get a bit warm there, so maybe that's caused the heat around. The localized heat around that area has caused that particular potting compound to go quite low.

cuz if we go over here, that one is perfectly fine. Check that out since of really corroded away. Top of that, literally they can there Wow it's terrible Muriel Alright, I've replaced the caps I've cleaned it up and let's give this one a go. This was the first one that let's give it a bell.

Hey No more fuss. Still doesn't work. Nothing coming out of there. no just came good I Expect this to have one of those.

Well, let's try that again. I'm good. Maybe there's another cap in there that should still be relatively easy to work and repair and troubleshoot something like this because so that's actually working fine now. So I don't know what that delay was there with the woofer.
Um, so unless it happens again I'm not gonna go tracing that one down, but this seems quite reasonable if a little booming I think on the preamp board. Anyway, we could actually. but yes and I guess by just does sound fine. it seems to be articulating speech Just brilliant.

Let's see if it that's Winston All right here's this faulty one which I have not powered up yet that had the same or similar tweeter excursion. loud oscillating issue that in my previous video head. so I've replaced the caps I've cleaned it up so let's turn it on. Where's the volume at here we go? Fingers crossed.

Oh I saw the light? come on. Whoa. hello. I saw that conics good and do the excursion again.

Put in conductive gunk on your boards, but it's become conductive with a age I'd say so. That's just an unbelievable issue, which as far as I'm aware, Krk just refuse to own up to. it is massively widespread. These two came from the same and the same set from the same person and both of them failed.

This is just like a plague. I Believe only the Gentoo speakers out there. either the six inch, the five inch, the 8 inch, or whatever art size it is. I believe they all have the same issue.

How many of them out there? Tens of thousands of them? I Don't know how many other Gen 2k okay's do they sell? They're one of the highest sell, you know, if not the highest-selling monitor speaker on the market at one point. Don't know if they still are, but yeah, it must be tons of these out there, so you might be able to pick up. Buy some decent bargains. If you search around on the eBay and other local classifieds and things like that, you should be able to clean them up.

Odds are you going to pick yourself up a decent set or a decent sounding set of and decently well-constructed I Do like how these are constructed anyway. There you have it. Hope you enjoyed that repair. Oh, you use these in the lab I think I just need one of those USB do daddy boxes and the RCA is not the best way to connect them up.

And I've just got that playing from my phone at the moment, that's you know. But it's They sound pretty decent. still. you know, need to evaluate the performance.

Compare them with my ELISA Sim One actives. Well, you know there could be other corrosion still on the boards within, so you know I'd be surprised if they're still working in 10 years time. maybe. But yeah, we know we know.

Chicken dinner? Hang on. There's something a little bit strange with these speakers and both of them do identical things. There's a little like crackling, sizzling noise in the tweeter and it's a regardless of volume. even at the lowest, right up to the highest.
It doesn't change. It's sort of like persistence in there. I'll try and turn the gain of my camera mic up and see if I can get it. So does anyone else who owns the Gentoo rotate like this? Do you get the same sort of very low level? We can't hear it, you have to put your ear right up to it, but that low level sort of crackling sound in the tweeter? It's it's not nice.

Anyway, if you liked that video, please give it a big thumbs up because that always helps a lot. I'll subscribe using the bell icon thing. go over here, subscribed and then you'll get notified. Maybe if YouTube decide their algorithm decides that they want to send you the notification.

As always, hours to subscribe to my Eevblog 2 channel as well and forum links down below and all the rest. catch you next time.

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By YTB

22 thoughts on “Eevblog #1073 – more krk rokit black gunk speaker repair”
  1. Avataaar/Circle Created with python_avatars Ignyte says:

    And years later, one of my gen two Rokit 5's just failed in the same way. No woofer, and now that you mention it, the hissing from the tweeter is far louder in the failed monitor compared to the one thats still working.

    The one that failed didnt do so suddenly though, the woofer would cut out randomly and only for a very short moment. But it got worse and worse with time until today, it's just not doing anything.

    Thanks for the vids as always, Dave. This will be instrumental in my repairs!

  2. Avataaar/Circle Created with python_avatars bkbaby347 says:

    Hey, can I replace the 2k resistors on the board with 2.2k resistors ?

  3. Avataaar/Circle Created with python_avatars glegalee says:

    Just picked up a set of these today for FREE ;P Have taken them apart and found the conductive gunk. Going to have a good go at cleaning and fixing them up. Thanks for the detailed video documenting the issue.

  4. Avataaar/Circle Created with python_avatars MrReeceyburger123 says:

    The new rok 5 has a junky smps in it I hate repairing it

  5. Avataaar/Circle Created with python_avatars Owen Brady says:

    same cap and resistor always goes first on all of them, they sound great when they work but the caps are just pure shite

  6. Avataaar/Circle Created with python_avatars Alex Prete says:

    The last two KRK I've fixed had these issues – if it might be helpful to anyone.
    KRK rp8 (no sound from woofer) – Bad electrolytic coupling the LF signal into the noninverting input of the TDA chip. (220uf 16v, close to the chassis)
    KRK rp5 (blowing fuses) – shorted diode in the rectifier for the higher voltage supply.

  7. Avataaar/Circle Created with python_avatars Gordon Welcher says:

    I used to see this gunk problem over 20 years ago on crt computer monitors.
    They have not learned to stop using this stuff.

  8. Avataaar/Circle Created with python_avatars Gordon Welcher says:

    Sometimes the liquid that come out of the gunk smells like vinegar. Vinegar is conductive. I think it helps to clean this with water, not contact cleaner.

  9. Avataaar/Circle Created with python_avatars Kish says:

    yeah i have this tweeter noise all the time. Recently had one of my rokit6 gen2 fail on me. The sub just isn't working right, outputting very low volumes in the mid range but nothing low. I don't know if i trust myself to fix it diy… i've only ever done very minor soldering before and getting components will be tough 🙁 If only there was a repair shop near me.

  10. Avataaar/Circle Created with python_avatars Paulo Gusmao Guedes says:

    Had the exact same problem on the woofer. Cleaned it up, and now it's working. Thank you very much. I can't hear a particular noise in the tweeter, though.

  11. Avataaar/Circle Created with python_avatars bkbaby347 says:

    Can I replace the 2k resistor with a 2.2k resistor ?

  12. Avataaar/Circle Created with python_avatars Ryan says:

    KRK should honor replacement on all these. this is insane.

  13. Avataaar/Circle Created with python_avatars Shad Young says:

    Once again, these are studio reference monitors designed for accurate mixing, not desktop speakers designed to "sound good". They are sealed and damped so that nothing colors the output, including noise from internal components. They do their job exceedingly well, and you need to spend considerably more to improve upon them. And unlike modern so called "studio speakers" from brands like Alesis, these are not DSP driven. The sound is natural, not processed.

  14. Avataaar/Circle Created with python_avatars Muppet B. Lansing says:

    Finally, a brand of caps lower down the ladder than "Jackon" caps. Ugh. Why do manufacturers do this?????

  15. Avataaar/Circle Created with python_avatars Shawn Sinohui says:

    Glad to find this video. One of my 10 year old KRK 5s loss the low freq. I opened it up and found the famous black goo melted to the PCB and components. It chips off kinda like peanut brittle with an Xacto blade. Be careful not to dig into the board and damage a trace. Also, you can't help but flex the caps and soldered components while chipping away at the burnt slather. As you flex the solder joints of a component, you may crack a solder joint, causing the component to work intermittently.

    It's a careful game to remove the melted insulating goop and not damage the PCB. I've done most of it, I'll report back on how my speaker works after I connect it.

  16. Avataaar/Circle Created with python_avatars QriZ says:

    What i dont understand: Where is this black gunk coming from?

    Never heard of that before and i have never seen it on any of my electronics. And i have opened a lot before.

  17. Avataaar/Circle Created with python_avatars Mako Goldshark 🤙🦈 says:

    my KRK PCB is covered in translucent yellow gunk instead of black gunk. All of the caps and resistors look fine but the speaker only gives a few seconds of sound before the sound cuts off (LED stays lit) until I turn it off/on again. Any ideas?

  18. Avataaar/Circle Created with python_avatars Damien Lobb says:

    It's miraculous that the second tweeter issue, didn't blow the tweeter like the first one you fixed.

  19. Avataaar/Circle Created with python_avatars WDaland says:

    Holy crap, thanks for this.
    Got two Rokit 5 RPG2, that both failed as well. Might actually open them up and check it out

  20. Avataaar/Circle Created with python_avatars David U says:

    Please they know exactly what it is…graphene oxide which is toxic.

  21. Avataaar/Circle Created with python_avatars patrick Hult says:

    Hi and a good video dude. Have you report this to KRK management or perhaps sent them this video about their speakers? If not plzzz do. Keep it up.

  22. Avataaar/Circle Created with python_avatars EEVblog says:

    Given all the "experts" on here with opinions of which speaker is best for studio mixing, what are the best monitor speaks for speech reproduction and why, i.e. video editing?

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