Harman Kardon HK775

[koumar]

I have the Harman Kardon. 775. Mono blocks. The problem that I'm having is turn on on one amp gives initial little buzz sound and goes away. The amp works perfectly after that. until the next startup. Does anyone have an idea? What is the problem? I adjusted the DC offset to zero. And the idle current to 36 millivolts.

 

[MrSound]

@koumar Could you do me a favor, please? Can you remove the bottom big plate and take a picture of the Boards? I think there are some components on the bottom boards, and they did not put them on the original schematic. I need to check as a reference for repair.

 

[huggygood]

https://www.reddit.com/media?url=ht...bp&s=74469ea8c9558202188946fc154968dca9c26c65

 

[MrSound]

@koumar This picture was taken after the rewiring. I know because i took the picture. There are some components on the bottom but i lost the images ,and i don't know did sombody before me addet them to the amplifier.

 

[MrSound]

@koumar It would help me if you made a picture of your AMP.

 

[MrSound]

@koumar And about the little buzz sound at startup, it is normal. The AMP has no relay switches or any type of circuit to delay the connection between the speakers at startup. I measured the initial signal at startup, and it is 2V.