Rotel RB990BX Grounding Issue

[smilan]

Hi, I have on the bench a Rotel rb-990bx power amplifier.
This amp have a serious grounding issues.
The input RCA jacks are disconnected from chassis ground and from each other.
I'm wondering if I can simply connect the sleeve of the input jack to ground? or by ding so I'll bypass the relay (RY801) circuit?
Here's a link to the service manual:

 

[JonSnell Electronic]

It does not actually see the relay as it is connected to ground. The relay just shunts the input after the 1k resistor to ground.
The manual shows it in the working position.

 

[smilan]

It does not actually see the relay as it is connected to ground. The relay just shunts the input after the 1k resistor to ground.
The manual shows it in the working position.

Thanks, so by connecting the relay pole (and the input jack sleeve) to the chassis ground I'll fix the ground loops and I won't bypass the relay circuit?
This connection (marked RED) is sown at the schematic, but does not exist in my amplifier (on both channels).

 

[rayma]

Yes, although the grounding point may be best to locate on the amplifier board.

 

[smilan]

Yes, although the grounding point may be best to locate on the amplifier board.

Thanks,
There are several ground connections on the main board, all connected to a star ground point (located on top of the large filtering caps.
The only ground connection that seems to be missing is the one between the input jack sleeve and the relay to the star ground point.

 

[johnmath]

There is a known issue with this Rotel model and others with poor connections through chassis screws. The solution may be as simple as tightening all of the screws.