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Repairing a KRK Rokit 6 powered near field studio monitor speaker.
You won't believe what caused the fault!
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Over the years, there have been a couple of repairs where I looked upon some gunk with suspicion - but I never found a case where it had actually contributed to the problem. I'm glad somebody did!!
Good job.
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It has been in the repair FAQ for a while.
http://www.repairfaq.org/sam/audiofaq.htm#audwgmtg -
To put some people at ease, I tore down my KRK V8 studio monitor which is their flagship and no sign of the black gunk now but clear epoxy... Still crap chinese capacitors though. Think I am going to rip them all out and put some decent quality stuff in as they are a well known failure mode for KRK monitors. Seriously do no companies take pride in their gear anymore... penny pinching on caps on flagship gear.
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Fault fixed, I wonder if the reason was that it had got wet at some point or if the gunk was absorbing moisture from the air. With all that corrosion I am not sure I would trust it long term, especially with a new tweeter just waiting for the fault to recur. Maybe it would be better to replace the power amplifier completely, or just convert it to a passive speaker.
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Hi Dave,
Greetings from a Brit in Belgium!
Thanks for this - I have been a long time silent viewer and learnt many things from you which bravely made me fix my mums electric shower and a whole host of other stuff. I recently got the Hakko FX-888D on your recommendation and am very happy with it. Gush over!
I found this vid really interesting because I am a bit of a computer geek, amateur composer and owner of a pair of KRK Rockit GII 5's for 7 years.
I've not had a problem in all that time (well, I did get a nasty hum once, but it turned out to be a dodgy power pack delivered with a Korean monitor import) and am very happy with - I found the black gunk you found to be worryingly "moist" maybe humidity or liquid?
Anyhoo, to address a couple of things you talked about, The main reason I bought monitors was for composing, mixing and mastering and specifically the "balanced audio" part (Would be great if you could do a vid on balanced vs unbalanced audio!). Most peeps buying monitors will probably be eyeing up an external (or internal) Audio interface, which in part answers your "I prefer mine with the volume knob on"
Mine is a Roland Rubix 22, which you can see in the images attached.
Keep up the awesome work,
Nicky.
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specifically the "balanced audio" part (Would be great if you could do a vid on balanced vs unbalanced audio!).
Ah yes. The difference between Pro Audio and the world of Audiofoolery. £20 for a XLR cable and thinking is it bloody expensive and those who pay 200~2000 for their magic Phono/RCA cable and are delighted with the money well spent and subsequent sound improvement.
Don't forget the voodoo oxygen free speaker cable to reproduce the rich real sound of mains 2 core 2.5mm HO7 (TRS) flex.
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Thanks!
This fixed my two week ongoing project! The timing of this I can't believe!
Check the goop, a new item on my checklist. -
There's a good reason for the housing around the outside of the RCA jack; it is there to prevent air leaks (just like the sealant around the other connectors.
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Dave, thank you for this video! I actually have a pair of the Rokit 6's in my wardrobe awaiting repair. Both have exactly the same symptom. They are actually half-decent speakers but they aren't exactly professional grade either.
I've also shot off an e-mail to KRK Systems / Gibson Customer Service regarding this issue. It's a widespread problem for anyone with these speakers. I'd say it would definitely be considered a "major failure" under Australian consumer law and despite the manufacturer's warranty having long run out, I think anyone in Australia with these speakers would be entitled to their money back or at the very least a replacement. Mine lasted about 12-18 months before they started exhibiting this issue. I wouldn't consider that to be "reasonably durable", would you?
I've also downloaded a copy of Dave's video in case KRK have any ideas to try and get the video taken down.
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Dave, thank you for this video! I actually have a pair of the Rokit 6's in my wardrobe awaiting repair. Both have exactly the same symptom. They are actually half-decent speakers but they aren't exactly professional grade either.
I've also shot off an e-mail to KRK Systems / Gibson Customer Service regarding this issue. It's a widespread problem for anyone with these speakers. I'd say it would definitely be considered a "major failure" under Australian consumer law and despite the manufacturer's warranty having long run out, I think anyone in Australia with these speakers would be entitled to their money back or at the very least a replacement. Mine lasted about 12-18 months before they started exhibiting this issue. I wouldn't consider that to be "reasonably durable", would you?
I've also downloaded a copy of Dave's video in case KRK have any ideas to try and get the video taken down.
It's very likely to be a capacitor issue also, very common on the Rokit series, I agree it completely unacceptable. My KRK V8 monitors cost $1700-$1800 and still they are using absolute garbage capacitors. It's a shame because other than the caps, the PCB layout is clean and well constructed at 17kg a piece. -
BTW, is it an OK practice to spread goop also on top of the capacitors (i.e. on the pressure valves)?
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Many years ago I used some acrylic sealant on 4 tags of a AC mains filter to stop me touching exposed 240 VAC.
I found out that conducted, as far as I can remember the mains was cooking the acrylic.
Also a lot of silicone sealants contain acetic acid which can corrode electronic circuits, metals and react
with alkaline based substances.
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The same happens to some KEF subwoofers.
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The capacitors in these things also go bad. In my KRK VXT4 the main caps rattled like maracas when shaken.
Also, indeed the gunk became conductive.
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ffcossag does audio repairs and sees this a lot: https://www.youtube.com/user/FFcossag
It's very likely to be a capacitor issue also, very common on the Rokit series, I agree it completely unacceptable. My KRK V8 monitors cost $1700-$1800 and still they are using absolute garbage capacitors. It's a shame because other than the caps, the PCB layout is clean and well constructed at 17kg a piece.
Thats inexcusable for a $2k USD product to use cheap caps... Speakers also have a very high margin, so its not like they aren't making much profit.
One problem is without their speakers failing, there is really very little reason to buy a new one. Its not like the performance of this years speaker is any better than ones you can get 10 or 20 years ago. -
Black gunk of death in my 2 years old gen 3 krk rokit 5
Also tons of transparent silicone like gunk, epoxy?
https://imgur.com/a/sbWZTbj -
Black gunk of death in my 2 years old gen 3 krk rokit 5
Also, cheap phenolic PCB for the PSU board? Also tons of transparent silicone like gunk, epoxy?
https://imgur.com/a/sbWZTbj -
Hi EEVblog,
which Generation of the Rokit 6 have you repaired?
Its interesting for people buying Rokits.
Thanks for your video, really great.
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Hi! I have the same problem with my monitor. The glue is conductive and has caused a few components to burst. At least C17, R104, R109 and R110. C17 has completely exploded, R104 is severely burned and R109/R110 has cracked. Does anyone have the service manual and/or parts list for this? Or could tell me the values of C17 and R104. It's a KRK Rokit 6 RPG2.
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Hi! I have the same problem with my monitor. The glue is conductive and has caused a few components to burst. At least C17, R104, R109 and R110. C17 has completely exploded, R104 is severely burned and R109/R110 has cracked. Does anyone have the service manual and/or parts list for this? Or could tell me the values of C17 and R104. It's an KRK Rokit 6 RPG2.
Here you go, full service manual
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Problem fixed
But the caps C100/C101 in mine were 3300uF, not 4700uF as in the schematics. They have the same original "conductive" glue all over them, so they seem factory installed. Did KRK cut corners after the initial schematics? 3300uF compared to 4700uF would probably lead to a negligible voltage drop on +/-15V rails at high loads (high volume level), which might lead to some distortions. Would replacing them with 4700uF make any improvement?
PS. I have rev. B monitors as mine has RL2 54.9K and RL101 4K75.
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Problem fixed
But the caps C100/C101 in mine were 3300uF, not 4700uF as in the schematics. They have the same original "conductive" glue all over them, so they seem factory installed. Did KRK cut corners after the initial schematics? 3300uF compared to 4700uF would probably lead to a negligible voltage drop on +/-15V rails at high loads (high volume level), which might lead to some distortions. Would replacing them with 4700uF make any improvement?
It's not just about the capacitance value, they lower values one might be a better quality brand, or have lower esr, or better life rating. In that case it could certainly be beneficial to change to the lower value. -
Sorry for reviving this topic, but I encountered another problem. The speaker would die after about 20 mins. DL100/DL101 (1N4148, mute circuit) was heavily corroded due to the conductive glue, so I replaced them. Sadly the replacements were faulty (they were put in the diode collection box by mistake, should have been discarded). They showed 2.7V in the reverse direction. After the replacement, the volume is very low, almost not detectable even on full. The diodes are a part of the mute input of the LF amplifier. But this doesn't explain why the HF speaker also is equally low in volume. I measured pin 10(MUTE)+15(-VS) on the LF amp (TDA7296), it reads 35V. Pin 1(STDBY GND)+10(MUTE) reads 6.5V (I'm not sure which GND the MUTE is referenced to). Measuring directly on the MUTE line (pin 6+8 on CN4-A) reads 8V. None of them within the 0-5V range according to the datasheet.
Any insight of what could be wrong? Perhaps these faulty diodes caused some other components to fail? -
Today one of my first generation Rokit 8 speakers decided to die. It turned out the culprits where faulty capacitors (C100 and C101 on the RP6G2 schematic, 4700uF / 50V / 105 degC). I also noted that there was a lot less of the glue on the board than the pictures I've seen of second generation speakers: basically just around the cables for the speakers and the capacitors. They did go wild with the stuff to make then entire assembly airtight though.
The glue itself is not (yet?) conductive in my case (with a bit of luck it stays that way).