Problem With KRK monitors losing power

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llanafreak44

Active member
Joined
Sep 12, 2009
Messages
28
Everytime I mix on these bastards, one speaker always starts to slowly lose volume, so I compensate by turning the volume up. Eventually, there's no more volume, and I suspect there's something wrong with the amp in the speaker. I'm thinking it might be a dying capacitor, but other than that, anyone know where I should start?
 
Which chips are they having in amps? Perhaps their thermal protection kicks in?

(At least this can happen with National LM chipamps, but from the top of my head, I think KRK use TDA???)
 
The chip amps in my RP8 are
DSCN0295.jpg


The tweeter amp chip is TDA2052 (left).
The woofer amp chip is TDA7294 (right).
 
A-ha, TDA's.. Could it be that the "mute" circuitry behaves badly?
 
pucho812 said:
obviously there is an issue with your amp inside. drop a note to KRK I'm sure they can point you in the right direction

They want to charge me 80$ to repair, plus they never answer emails. Probably the worst customer service I've ever dealt with.  :mad:
 
They want to charge me 80$ to repair, plus they never answer emails. Probably the worst customer service I've ever dealt with.  :mad:
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Still in warranty? I have RP8 here, not like it vey much. I opened and change all cheap opamp. Not very complicated inside. The TDA is mounted at back plate. Is the back plate getting hot?
 
+1 for garbage customer service from the almighty krk. Good luck getting a schematic or any service hints. Apparently their designs are incredible industry secrets.

It sounds like the problem would almost definitely be caused by a component overheating or possibly a temperature sensor failure?

Buy a can of component cooler from radio shack and start spraying components back down to room temperature one by one. Obviously keep the volume down since if you do find the heat-induced problem it's going to jump back up pretty quickly as you'll be changing the temperature pretty quickly.
 
I'd check for bad capacitors anywhere on the main board.  Its most common failure with those units.  I recommend that anytime 1 capacitor finally goes bad(eventually they all will) to replace them all.  Google the term 'bad capacitors' and you will see pictures of what they look like.  If you don't see any then just do as suggested in previous posts, see if the head sink, that the TDA chip is connected, is getting too hot to touch, if it is i'd replace both the chips just to be safe and save the headache of guessing.  If this doesn't fix it they only other possibility really is a overheated solder joint that slowly goes bad, but thats a long shot.  Also $80 is really not a bad repair quote to fix the problem, just saying.
 
riggler - it looks like krk just did an overall terrible assembly job with the board. caps are lopsided all over the place!

p.s. - where in PA are you?
 
not sure if you got your trouble situated yet, but somebody's currently parting out a bunch of krk rokit stuff on ebay, including amplifier sections. May be of interest.
 

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