Krell 707 problem need help

Hi. I am seeking some help regarding the Krell 707 processor. 

Lately, after some playing time - a started coming out of the speakers.  If I turned the 707 off and on again - the noise was gone, but returned later.  

Then one day, this rush became a loud screech, after which both amps (Krell) shut down. It sounded like an explosion. 

Now, an interesting thing: this phenomenon did not occur in either XLR or SPDIF inputs! Only in RCA. 

I contacted Krell and their response was: send it to factory. Alas, I live abroad so it is out of the question.  

A local technician who checked the machine didn't find any malfunction. He suspected some DC leak somewhere but warned it could cost a fortune to locate it.  

So my question is: has anybody here ever encountered such a problem in Krell or even more generally? And if so - were you able to solve it without shipping the amp to the manufacturer?

I would appreciate any input. 



If you are having issues with the RCA outputs, are you able to switch to other type of outputs such as CAST or XLR if you amp has these kind of  inputs.  I use CAST on my 707.

Have  you tried cleaning the contacts the RCA connectors?  

lastly, you can ask Krell for the schematics and they may give it you since it’s a very old product.