I am still having problems with the left ch. output on my Mackie Onyx 32-4. When you first turn it on there is no left channel output. But you can get it back by driving a source to the limit and the audio with POP in. I took it a part three weeks ago and checked all the connections and put it back together. It was working OK until a week ago but now it is back. I see that the power supply is separate and it looks OK. I am thinking it is on the Main board of the mixer and it is somewhere in the output section. I know it is a tough question but I thought I would ask everyone and see what happens. Otherwise I will be taking it to an authorized Mackie dealer, wherever that is in Southern Alberta. Thanks for reading this
Audio Players & Recorders - Mackie - Onyx 32.4 32-Channel Mixer
Answers & Comments
If it's not the cables that you are using, it could be a number of things. Bad solder connection or corrosion on one or more ribbon cables. Maybe a weak return contact on a 1/4 inch female jack. Try putting a signal into the mixer and then inserting a male 1/4 inch plug into the different jacks to find out which jacks disconnect the signal when inserted. Even when they are not used these jacks tend to become slightly corroded and the signal is lost. You can give the jacks a burst of contact spray and 'work' a male plug in and out of the jack a dozen times.
Thank you so much for your ideas Len and I'm terribly sorry for replying so late. I agree with all you say and I've tested the 1/4" jacks. It didn't help the problem though but I cleaned them anyways. This is why I need the schematic of the output circuit so I can follow the audio path. It's difficult also because the L ch. can be out for two min. or ten min. and then pop in. But thanks for your help. I really appreciate it!