KRK Rokit 6 - Sound for a bit then cuts out

[jeremyrichardson]

Hi there,

I'm new to tinkering with electronics so I'm looking for some help figuring out even where to look and how to test. Thanks to anyone willing to help.

KRK 6 speaker will usually work when first turned on but then will turn off after a random amount of time. Sometimes it's 10 seconds but yesterday it ran all day without cutting out. It usually pops slightly when it turns off, similar to when it's powered off with the power switch.

I can confirm the logo remains lighted on the front at all times even when there is no sound.

Black Goo
I've watched some videos and read up on the black goo issue that these KRKs seem to suffer from. I opened up the speaker and scraped off some of the black goo. Without removing parts it's really hard to get at most of it, but got what I could.

Suggestions as to what to test and how?
Without really knowing electronics, it seems to me that something is overloading and sending the speaker into a safe mode or something. Nothing is really getting physically hot since they really aren't on for long before they shut off, but maybe a component is failing?

Any help pointing me in the right direction would be most appreciated.

[Audiorepair]

Its the black goo.
You haven't removed enough of it yet, it puts the unit into Mute.

It also corrodes some component leads and resistor bodies, so you may have to replace one or two if it's got really bad.


This stuff is good at getting it off the PCB once it has gone brittle, corrosive and conductive, but not so good at the squidgy version that hasn't yet.
https://cpc.farnell.com/servisol/100019000/servisol-de-flux-160/dp/SA00962



I've done this enough times to have kept a record of the resistors that usually suffer most, or are impossible to read the colour codes:

Rokit 6 R100 2K2 between main caps
R105 4k7  RH100 10k  RH101 11k
RL106 30K RH105 10K R108 2K
RH104 11K


The first one, R100, is often the first to go, and sometimes the only one.

[jeremyrichardson]

Well that gives me hope!

I guess I'll need to test my soldering skills since I can't really get much more of the black good without removing somethings.

I'll try and remove the minimum amount but things like the leads that go to the drivers themselves, I can't for the life of me figure out how to disconnect the clips. And the one for the tweeter is so deep in there I can't see how to possibly get it off. So I'm thinking to remove the wire at the solder point on the board and then I should be able to remove it better.

Thanks again.

[Audiorepair]

The speaker connectors are spade connectors and just pull off.
Often, though, they are very tight, and need pliers, and then you run the risk of damaging the drivers.

You really need to remove the speaker cables from the board anyway, as you will find the huge amount of black goo placed around where they are soldered will have damaged the wire and made it brittle, so probably best to just go ahead and cut them off to remove the PCB from the cabinet, and then cut the damaged parts off the cables on reassembly.