Hum coming from Monitor Mix

Hi all, been using a Qu 24 for about 2 years now. About a week or two ago, monitor mix 2 started having issues. I am getting a loud hum from mix 2, like a ground loop. I can still hear the the audio being sent to mix 2, but the hum is much louder. Doing some troubleshooting, it is only coming from monitor mix 2. Plugging the monitor into another mix output works fine, and any monitor/speaker plugged into mix 2 will produce hum. Are there any suggestions or options to try before factory resetting or sending it in for servicing?

Some additional information. This is plugging monitor or amplified speaker into xlr output from the back of the mixer. The volume of the hum is constant and does not change when moving the fader volume for mix 2.

maybe the socket is broken…

If indeed you can plug that same XLR cable into any other XLR audio on the board and it works fine I’m going with a broken XLR as well. Try plugging in to the mix 2 jack and with the speaker humming try moving the connector around some and see that make the hum
stop.

It could be a broken connection where the XLR jack is soldered to the circuit board and moving it some may cause the hum to stop…at least while you hold the connector!

My guess is pin 2 or 3 on the mix 2 XLR jack are open either from a broken jack or in the actual circuit itself.

Another question, when you have the hum on mix 2 is there anything else
connected to the mixer?