Studio Monitor repair help

[Carnesd]

So just for background first I'm not a complete Noobie to electrical circuits but I am definitly not anywhere near the level of guys here so bare with my laymen terms please. 
I've got a KRK studio monitor that I am trying to repair,  the woofer is getting straight dc voltage when powering on the monitor.  From the research I've done I am getting the DC voltage from the power supply into the audio signal.  Of course I can't find a schematic online anywhere.  So I've been checking what I can and have started to narrow it down but now I am stuck. 

I've checked power from the tranformer and have the correct voltage to the board, 
The unit uses 2 amplifier IC's  TDA 2052's, one is for the tweeter and one for the woofer.  I've traced the DC voltage which I'm getting 25v switching to -25v repeatedly back down to the 2052 ic.   
1.  At the 2052 chip I've got -Vs and +Vs as -24v and +24v which I assume is correct. 
2.  At pin 1 which I have the -24 and 24 switching which is the output to the speaker
3. Pin 7 which I am assuming is the audio signal to the amp is switching between 2.5v and -2.5v

Am I right in assuming I have a problem in the audio circuit before the Amplifier IC?  Or could the IC be bad putting the dc voltage back on the audio circuit input?


IC  http://www.st.com/content/ccc/resource/technical/document/datasheet/29/e0/cd/df/17/65/48/c8/CD00000208.pdf/files/CD00000208.pdf/jcr:content/translations/en.CD00000208.pdf

 

[nashkato]

Hi
Don´t know if this is in any way related to your problem .
I repaired a KRK active Subwoofer once which had the problem that there was loud cracking on both the sub and the mid/hi outputs.
This seems to be  a common problem with KRK Monitors .
I didn´t find a manual as well , and spend quite some time on the Powersupply only to find that the problem was some bad ceramic capacitors in the preamp around one of the OPV ´s.

Since i´ve read that many KRK show the same symptoms it may worth checking out the in/outputs of the preamp OPV´s with an oscilloscope , if you have one  , if one or some of the ceramic caps leak DC into the circuit .

 

[Carnesd]

I'm betting your right it probably is a capacitor,  unfortunately  I don't have a scope, and the capacitors all look ok,  I think I may just trace the input signal back to the connector on the board and go through and pull each capacitor out and test them and see what happens. 

Mainly I guess my question is,  is there a way to tell where the dc voltage is getting into the audio path with just a multimeter?
I know this is all dependent on the circuit but some strategies would be helpful.

Thanks again.

 

[nashkato]

if you pull them out , you can change them to new ones when you´re at it ( ceramic caps are cheap ).

without a scope i would pull all OPV´s ,  turn the speaker on and see what happens .
if the problem disappeared put them back in in reverse order of signal path until the problem reappears .
( oh , i just realized they´re most probably not in sockets  , so , too much work  i guess )

You can always set your MM on DC , and compare to the healthy second speaker if you can find something that looks suspicious .