Chosen Solution
I have a rather old Sony receiver that claims it’s a STR AV-910. It has connections for four speakers, A and B with left and right options for both. For some reason, the left side speakers for both A and B connections make crackling noises whenever they’re plugged in. They will play music, but it is extremely staticky. I’ve removed the back and checked the wiring, but I can’t see anything obvious that might be causing the problem.
Hi @pianomacpower , Do you hear the crackle when using headphones? If not it may be dirty contacts in the A/B speaker selector switch or a dry joint left channel connection to the switch. If so it may be dirty contacts in the protection relay (RY701) or a problem further back in the amp stage. Here’s an image from the service manual that may help.
(click on image to enlarge)
