Gemini GVX-12P with random popping noise

[phantombox]

Hi guys.
I have a Gemini GVX-12P and GVX-15P with random popping noise on my desk for repair. These are powered stage monitors from around 2011.
I already checked all caps on the PSU and main amp section for leakage with a LED and variable supply voltage.
There is another GVX-12P that had a broken main power switch. I could swap the PSU section with the other GVX-12P and GVX-15P and noise did not migrate, so it comes definitely from the main amp section.
So I resoldered all connecting points of all components.
Then I put a 'scope to the amp and could see a sine wave all the way but I have no clue of what exactly to look for. Nor how to interpret it. (To be honest, I rarely use an oscilloscope).
I already took the amp section appart (pain in the but!) and reassembled it with a bunch of wires separating the main amp section from the power transistors in order to test it "open style".
On another forum, Duncan2 from Great Britain pointed out that "it sounds like a "breaking up" or bad connection of (usually) a resistor but a signal path capacitor could cause it."
I'm attaching the audio file, and some pics.
And I cannot find any schematics of this monitor online.
Any help would be highly appreciated.

 

[phantombox]

The popping pop-noise originates in the LF amp. I disconnected the PCB opposite of the transformer, with preamp and crossover on the same board. There is a connector with separate outputs for the HF and LF amp on it, the inputs are on the main PCB (with the relay on it).

 

[Denison dos Santos]

pode me enviar a foto nítida da placa??
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