Mackie CR4 (probably Zenner diodes burned.

Thread Starter

gallardoedgar

Joined Jul 4, 2020
5
Hello Everyone this is my first post... I have the Mackie CR4 audio monitors, and I see the PCB is kind of burned (images attached).

I do believe the Z3 and Z4 zenners were overheated but I'm not really sure.

I don't know the part numbers for those or if I'm missing something, I would appreciate any help on this. I can't seem to find an schematic that includes the Z3 and Z4 part for the Mackie's CR4.

Thanks everyoneIMG_20200704_172317.jpg
IMG_20200704_172331.jpg
 

Thread Starter

gallardoedgar

Joined Jul 4, 2020
5
You would have to turn the board around to see which traces have overheated. That will give you a clue.
After some research it seems it's a "common problem" with these models.

I proceeded as stated in the following video:

Explained in an image here... cut.png

Seriously... After I did this... everything is working perfectly fine now.

Thanks for your support guys
 

dkrn9000

Joined Oct 6, 2020
1
I'm so happy I found this thread. I had the exact same problem. The PCB looked burned just like in your images and I was also trying to replace the zener diodes, but this youtube tutorial worked like a charm!
 

nickalla

Joined Nov 20, 2020
1
Hi guys, have a similar problem in my CR4. The C80 capacitor completely blew its top shedding electrolyte everywhere. Anypne have any ide on a likely value? I Iam thinking 100uF but grateful if anyone can confirm. Also what value zener diodes? I am also thinking 3.3v eg 1N4728 or similar. They seem to use Z prefix on PCB lettering to mean 1N4148 small switching type diode as well as zener. Can anyone confirm please? Thanks in anticipation
 
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