Soundcraft si expression, unknown error sound

[San Ko]

Hi, If anyone familiar with using a mixer Soundcraft si expression, please take a look at my situation.

My system makes unknown error sound when I go to BUS mode by pushing any MIX button.

The sound is not just howling, rather it is very high "bee-----" sound. It goes away either I fade down the main fader or I push "SOLO CLR" button in the BUS mode.

Do you have any guess why this happens?

 

[Chris Hindle]

Sounds like a routing problem.
I think you have an output feeding an input somewhere.
Chris.