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Im very sorry to hear you are having poppong sounds coming from the Mac computer......and I do not have good news for you, unfortunately.
YOu are having hardware failure......and you need to power this machine OFF IMMEDIATELY, as what you are describing can lead to the machine potentially catching fire.
Once the machine is off, you MUST take it in to a service center..
There is no troubleshooting a consumer can do.
Opening another request wont help.
It will be closed as duplicate request.
Im sorry to give you this news......but when your computer makes popping sounds, you need to power the machine OFF IMMEDIATLY.
Then pull the computer apart and test each component individually for the culprit.
Theres nothign you can do unless you have a computer technical Testing Bench for Apple products?