DP-01 channel fader issue

[Earthunsee]

Recently purchased a DP-01 (had one years ago and used it all the time and wanted to use it again for a specific project)...its working amazingly with one issue. Channel 5 doesn't respond at all to the fader. It records ok and the mute button works but the fader doesn't. Any ideas how to fix this? Isn't the end of the world but would be nice to have 8 working channels instead of 7.