I have a problem with the receiver for my 5.1 system.
When I turn it on, the speakers start making a popping sound that continues for a few minutes. I have tried disconnecting the speakers and using different ones, as well as different inputs, but the issue remains the same. The popping lasts for a shorter time if the receiver has been turned off for a while. Initially, it only lasted a few seconds, but it has gradually got worse.
Watch the video to hear the sound. In the video, I have only connected one speaker.
The receiver is a Marantz NR1501. I'm not sure when I bought it, but I found a review from 2010.
I opened the receiver and inspected it, but I can't see anything burnt, and all the capacitors look OK.
Do you have any idea what the issue is? How can I confirm if that is the root cause?
That does appear to be the adhesive used to secure tall/heavy components so that they don't break off during shipping or when lightly impacted.