Maybe it's a resistance that needs to be replaced but I'm not sure.
SONY STR-K750P Digital Audio/Video Control Center FM AM Stereo Receiver
I have this somewhat older system (Sony STR-K750P), wondering if it's worth holding onto for a new turntable setup I'm working on. No dedicated phono input. Thoughts? : r/audio
Sony Stereo AM FM Receiver STR-K750P TESTED and Working
See the last two photos. Tested - working. Sounds great. No remote.
Sony STR-K750P Digital Audio/Video Control Center FM Stereo Receiver AMFM Tested
Sony Amplifier Str FOR SALE! - PicClick AU
SONY STR-K750P 5.1 AM FM Stereo Surround Receiver with Remote Optical Input Photo #1042487 - US Audio Mart
Sony STR-K740P - 100 Watts
Sony STR-K750P 5.1 Channel 575 Watt Receiver Original owner complete working look at pics for condition everything works subwoofer might have some of for Sale in Corona, CA - OfferUp
See the last two photos. Tested - working. Sounds great. No remote.
Sony STR-K750P Digital Audio/Video Control Center FM Stereo Receiver AMFM Tested