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 everyone

 

Putting the blame on bad zeners Z3 and Z4 seems like a long shot.
Plug in headphones and see if the headphones work.

 

I agree with MrChips.

The solution is simple:
A zener is a diode after all. With a DMM in diode mode, check the integrity of both.

 

Headphones actually work MrChips, any ideas on how to proceed?

 

Putting the blame on bad zeners Z3 and Z4 seems like a long shot.
Plug in headphones and see if the headphones work.

Headphones actually work MrChips, any ideas on how to proceed?

 

I agree with MrChips.

The solution is simple:
A zener is a diode after all. With a DMM in diode mode, check the integrity of both.

Thank you as well schmitt trigger, headphones do work, any ideas on what might the issue would be?

 

You would have to turn the board around to see which traces have overheated. That will give you a clue.

 

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...

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

Thanks for your support guys

 

Glad to hear you got it resolved.
Mackie CR3 and CR4 use a TDA7265 power amp IC.
Pin-5 is Standby/Mute/Play control.

 

@gallardoedgar thank you very much, everything is working perfectly well now.

 

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!

 

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

 

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

YOu are right the capacitor C80 is 16V and 100uF. On mine the C81 blown up, I believe it's same as the C80 but i wonder if anyone confirm

 

YOu are right the capacitor C80 is 16V and 100uF. On mine the C81 blown up, I believe it's same as the C80 but i wonder if anyone confirm

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!

Just to mention, desoldering pin 5 and bridging to pin 9 gets rid of all annoying noise that appears when just pin 5 is released. Working like a charm with that solution. Just leave pin 9 in place, desolder pin 5 and pull upwards, then bridge it to pin 9.

 

Sorry, couldn’t delete this one.

 

A friend of mine has a Pair of the CR4BT. And they had no power. Noticed an area that was almost burnt. So I checked to see if Z3 or Z4 shorted. Yep Z3 shorted, no +12 volts. Also found C80 had a slight dis-color and top was not mushroomed up but it looked different. Replaced both C80 & C81. I could not find schematics for the CR4BT version even contacted Mackie and they don't have the schematics for the version I'm trying to fix. The CR3 schematic is kind of close but R1 & R2 say 220 ohms. But on the CR4 they are 100 ohms 2 watt resistors. Found pictures of the board I have on the FCC web site. They didn't have schematics but they did have pictures of the board and it was an exact match. And R1 & R2 are 100 ohm 2 watt resistors. The FCC ID I looked is 2AD4XCR4BTCR5BT. First 5 characters are the company ID and the rest is device. So for anyone looking up info on any electronic device check here: https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm . Hope this helps anyone else!! Speakers sound great!

 

Mackie CR3. I know this is an old post, but still relevant. The zener diodes Z3 and Z4 are both 1N4742A. C74, C80, C81 are each 100uf 16v but were reading in the pf range. probably overheated by the diodes, which were running over 250 degF. R1 and R2 are 220ohm on schematic, but are actually 100ohm in circuit

 

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 everyoneView attachment 211391
View attachment 211392

Exactly the same problem here, definitely a common issue.