Tunwe
I think the black goop caused the corrosion

Absolutely it did!  The same as my set of KRK's and the same as others'.
 
The Black Goop strikes again!

I recently fixed a KRK Rokit 5. The TDA2052 was broken and I replaced it. Replaced the Elco's 2200 uF 50V and 1000uF 50V as well and still the woofer had a full power continuous low sound on power up. In the end I replaced almost all elco's. After replacing the 2 - 10uF 50V bipolar elco's and cleaning the black goop it finally powered up fine! Not sure if it was only the black goop or a combination of the bipolar elco's and the goop.
Thank you all for the contribution to this post and of course the topic starter. 

RicoRoyal
I recently fixed a KRK Rokit 5. The TDA2052 was broken and I replaced it. Replaced the Elco's 2200 uF 50V and 1000uF 50V as well and still the woofer had a full power continuous low sound on power up. In the end I replaced almost all elco's. After replacing the 2 - 10uF 50V bipolar elco's and cleaning the black goop it finally powered up fine! Not sure if it was only the black goop or a combination of the bipolar elco's and the goop.
Thank you all for the contribution to this post and of course the topic starter.

Congrats on the fix!  Root cause of all component failures: goop.

2:43AM - Hey man great forum i have the rockit 5s and my one monitor has the exact issue...it pops and crackles and then after a little bit seems to go away more or less...i opened it up to check the components and ill throw up a picture but im not farmiliar with changing them out or how to know if they need to be replaced...im going to try and remove the goop which is such a dumb messy thing to put on a circuit board...i put them back together but now on top of the crackle theirs a hum sound that wasnt hsir before ....i feel i should have just not taken them apart at all but i really want to get them fixed so if i send a pic would you maybe have a look to see if you can see what components need replacing if any
..thanks in advance

sloppyjoe44
2:43AM - Hey man great forum i have the rockit 5s and my one monitor has the exact issue...it pops and crackles and then after a little bit seems to go away more or less...i opened it up to check the components and ill throw up a picture but im not farmiliar with changing them out or how to know if they need to be replaced...im going to try and remove the goop which is such a dumb messy thing to put on a circuit board...i put them back together but now on top of the crackle theirs a hum sound that wasnt hsir before ....i feel i should have just not taken them apart at all but i really want to get them fixed so if i send a pic would you maybe have a look to see if you can see what components need replacing if any
..thanks in advance

Thanks, Joey.  Post a picture, if you can.  That may help out a bit.  Overall, the black goop is the root-cause of the audio problems/hum/static and the component failures.  I agree that is was completely asinine for KRK to put the goop on the boards, but their intention was to keep components from vibrating and making noise and/or coming loose.  I would hope they were unaware that it was conductive or would become conductive over time.  Either way, super poor choice!  Usually, white silicone is used to hold components/connectors together on PCB's, but KRK must have thought it would be too expensive and went with a cheaper source/vendor.  And here we all...probably thousands of failing KRK speakers out there!
 
Anyway, as far as the "hum" you're hearing...did you try to remove any black goop prior to reassembly?  Did you do anything while it was apart?  If you did indeed try to remove the goop, it may not have been thorough enough.  Any traces left will cause issues.  Pay particular attention to areas where the jumpers are located.  If no goop was removed, then you have have a connection that wiggled loose.
 
Finally, put it this way: don't feel bad for taking them apart.  Even though the hum is there now, they are no worse than they were before!

Well i found out that one corner of the circuit board broke so i have to try and repair that which is probably my root of evil but ill still send a pix of the components i think might be an issue

sloppyjoe44
Well i found out that one corner of the circuit board broke so i have to try and repair that which is probably my root of evil but ill still send a pix of the components i think might be an issue

Rebuilding a a broken trace is rather simple.  Let me know if you need help with that as well.

Hi, can anyone help me to identify some damaged components on this board?
 
I'm looking at diodes DL100 and DL101 near the TDA7296. I got a partial reading off of DL100 and I think its a 1N4148 signal diode. Can anyone confirm this? DL101 is completely destroyed by the Black-Goop-Of-Death, but I'm thinking its probably a 1N4148 as well...
 
Cheers

neilbags
Hi, can anyone help me to identify some damaged components on this board?
 
I'm looking at diodes DL100 and DL101 near the TDA7296. I got a partial reading off of DL100 and I think its a 1N4148 signal diode. Can anyone confirm this? DL101 is completely destroyed by the Black-Goop-Of-Death, but I'm thinking its probably a 1N4148 as well...

 
I don't have a picture to reference of these particular diodes.  Can you follow the traces back to see where they connect?  Determining diodes is quite difficult without a schematic, which surprisingly, has yet to be found.  If they're plain old rectifier diodes, let's say if they're connected to the larger capacitors and also the incoming wires from the power transformer, then replacement is pretty straightforward and a 1N4004 should do the trick.  If it's a small-signal (or switching diode), then replacement may be a bit trickier, but your guesstimate of a 1N4148 may be adequate as well.  The trick with a small-signal diode is to find one that will a) handle the forward current and b) switch fast enough in the transients.  Personally, I don't think KRK is using any high-end components on these boards, and the diode is most likely a rectifier.
 
What are the symptoms of your speakers?  Are they not powering up?  Furthermore, what do you mean by "partial reading?"  Do you mean a DMM's voltage/diode test of 0.6-0.8V or a visual "reading" of the part number inscribed on the component itself?
 
 

2:43AM
I don't have a picture to reference of these particular diodes.  Can you follow the traces back to see where they connect?  Determining diodes is quite difficult without a schematic, which surprisingly, has yet to be found.  If they're plain old rectifier diodes, let's say if they're connected to the larger capacitors and also the incoming wires from the power transformer, then replacement is pretty straightforward and a 1N4004 should do the trick.  If it's a small-signal (or switching diode), then replacement may be a bit trickier, but your guesstimate of a 1N4148 may be adequate as well.  The trick with a small-signal diode is to find one that will a) handle the forward current and b) switch fast enough in the transients.  Personally, I don't think KRK is using any high-end components on these boards, and the diode is most likely a rectifier.
 
What are the symptoms of your speakers?  Are they not powering up?  Furthermore, what do you mean by "partial reading?"  Do you mean a DMM's voltage/diode test of 0.6-0.8V or a visual "reading" of the part number inscribed on the component itself?
 

 
They are the glass diodes near the centre of your photo from page 1:
 

 
I managed to read something visually from DL100 which looked like N4148. DL101 was totally unreadable. The forward voltage is 0.7v. In your picture they both look the same but in mine they look like slightly different parts. The cathodes are tied together and appear to go (via resistors) to the standby and standby-gnd pins of the TDA7236, although I'm not 100% sure. I'll try to take another look tomorrow. The anodes shoot seem to shoot over different ends of the board - I didnt really look that closely.
 
I have two broken Rokit 6's - one is crackly and the mid-woofer drops in and out, and the other makes some clicking sound at a fixed frequency of a few Hz. Both have severe black-goop damage at multiple regions of the board. I've almost finished fixing one (the clicky one) using some parts from the other (more damaged) board. Once this one is ok I'll order some parts to fill in some gaps from the doner board and clean that one up as well.
 
These monitors have a nice sound. Too bad the build quality is so terrible