No audio coming out of Mackie CR3 Studio Monitors

"I picked up a set of these from a wholesale liquidator auction site and had the same issue. I tried replacing the amp chip but no good. Finally as a last ditch effort before throwing them away, I cut pin 5 on the amp chip (TDA7265) which was the mute pin. I get sound from the speakers now, but they don't mute when I plug in headphones, which is fine by me. Everything else works as intended it seems.

Probably not the ideal fix, but it works for me."

Plug in and remove your headphones a few times really fast it sounds stupid but it will work

"To comfirm, when looking at the chip attached to the heat sink, the pin I have drawn a yellow line from in the diagram (the 3rd long pin in starting from the right hand side (at pin 1) with the heat sink behind the chip - you will notice pin 1 and pin 5 are both long pins forming a total of 6 long pins and nesting adjacent (underneath) each of these long pins are 5 smaller pins forming a total of 11 pins) is DEFINATELY the one you cut if having this no sound through the main speaker issue! It simply means the speakers won’t mute when you plug your headphones into the jack.

Please see pin 5 in the diagram below as explained above:"

i have same problem on my CR3..solved by removing the R88 (1k ohm resistor) and changing with new one…cutting pin 5 of the ic chip will deactivated mute circuit and resulting popping sound when turn on/off main switch

"The real problem is sometimes further in the circuit. Like ‘forest’ was saying in another topic I fixed a couple of them by replacing only the z4 zener diode. It gets really hot during operation, and stuff just breaks:

Had the same issue, caused by the heat around Z4 diode. Fixed by replacing the dead cap C74 (100u/16v) and the diode Z4 (12v 1W zener 1N4742), check maybe you need to replace more components, R2 for example. This area of the pcb is generating “mute” signal for the amp, so no wonder the trick of cutting “mute” pin of tda7265 works sometimes

If you want the simple solution. you don't have to cut the pin (messy), just cut the jumper in the red box:"

As spraying Contact Cleaner only fixes the issue for a month or so for me, I went in with a Multimeter, and figured out how to just bypass the switch altogether. Makes your ‘selection’ permanent, but not a big deal for keeping the speakers out of the trash. I clumsily wrote my first guide ever on how to do it yourself, hope this helps others: Mackie CR3 CR4 L/R Speaker Selector Bypass Labeled ‘difficult’ because it requires soldering, but if you are comfortable with that, this is a quick and easy fix.