main outs not working. is this a common issue?

I've had this MPC1000 repair on the back burner so long I finally got the new pads on it everything works great except no sound from the main outs nor the headphone jack. I am certain that I am assigning sounds correctly because I can get individual outs 1-4 to work as normal. You can imagine how frustrating this is because it is only possible to monitor/edit samples from the main/headphone outs!

Obviously I'm going to double check all the ribbon cables when I peak in there again but if anyone knows this to be a common issue it would save me the headache thanks!!!