Channel 3 and 4 audio always leaks to channel 2 -- faders 3 and 4 non-functional

Hello. Recently an issue has emerged with our X1800 mixer. Before I describe the issue I’ll describe how we have the mixer set up with the 2 SC5000s. 2 SC5000s are plugged into the mixer via digital inputs. Deck 1 is plugged into ethernet #1 and deck 2 is plugged into ethernet #2. Layer A on deck 1 goes into digital input 1 and layer B goes into digital input 3. Layer A on deck 2 goes into digital input 2 and layer B goes into digital input 4.

The issue we are experiencing is as follows – when any input is flowing through channels 3 or 4, whether it be a line input plugged directly into channel 3 or 4 of the mixer or layer B on the decks flowing into channel 3 or 4, the audio does not come out of those channels regardless of channel 3 or 4 fader position. However, if the channel 2 fader is up we can hear the audio from channels 3 or 4. Summarized, the signal going into channels 3 and 4 always leaks into channel 2. Faders 3 and 4 are essentially useless as they do not control the audio levels for those channels. The only way to hear audio from channels 3 or 4 is by making sure the channel 2 fader is turned on.

I have tried many things in attempt to remedy this issue. I have upgraded and downgraded firmware and even unplugged the SC5000 decks from the mixer and tried plugging an external audio source into line channels 3 and 4. Regardless of the setup or whether the SC5000s are connected, audio flowing into channels 3 or 4 will only ever be heard if the channel 2 fader is up. This essentially makes channels 3 and 4 useless as they cannot be controlled separately.

Please let me know if there are any other steps I should try to remedy this. I am worried this is a hardware issue and will require replacement or service.

Thanks! Jack

Check that your FX Cue isn’t on, that causes bleeding.