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Greetings of Peace! Great forum guys i am learning alot 
just wanted to seek your advice regarding the Roland Cube80XL i am tryin to fix.
Crackling Noise comes out of the speaker after 5-10minutes upon power on regardless of volume or channel.
i have isolated the problem before the power amp board section. tru the ff
1. checked audio signal quality tru Lineout. No crackling sound
2. plugged my headphones tru the Phones output, Crackling is present
Questions:
1. what is the purpose of pushpull config Q12 & Q13 after DAC (please see attached file) im suspecting theres a problem here.
2. how to check if capacitors are ok, another suspect is that there is a problem with a capacitor in this section.
just wanted to seek your advice regarding the Roland Cube80XL i am tryin to fix.Crackling Noise comes out of the speaker after 5-10minutes upon power on regardless of volume or channel.
i have isolated the problem before the power amp board section. tru the ff
1. checked audio signal quality tru Lineout. No crackling sound
2. plugged my headphones tru the Phones output, Crackling is present
Questions:
1. what is the purpose of pushpull config Q12 & Q13 after DAC (please see attached file) im suspecting theres a problem here.
2. how to check if capacitors are ok, another suspect is that there is a problem with a capacitor in this section.
Attached Files