Ps3 - Audio Problems In Games

Hey all,

Not sure if this is the place to post about console problems but I thought I'd give it a try. I bought a 2nd hand PS3 recently which has turned out to be in more of a state than I thought (no surprises there I suppose...). It's clearly come from a household that smokes as there is a brown dusty buildup in all of the air inlets.

Anyway, the main problem is the audio. They didn't supply the original (or any...) AV cable so I'm using my own HDMI cable, which I know is fine, to connect it to my PC monitor. On startup and in the menu it's fine, even playing music CD's and videos on the web browser, the audio sounds normal. However when I start up a game it makes a horrible constant and very loud chirping noise that comes out of the monitor's speakers (turning the monitor's volume to 0 stops the noise, but also, obviously, makes my game silent) and there is no in-game audio, not even distorted or quiet behind the chirping. Kind of sounds like the noise a cricket/grasshopper makes but non-stop.

Any idea how I could fix this? Probably can't get a refund as it was from a private seller on Facebook Marketplace. Could using the PS3's TOSLINK digital output or AV analog output get around this? Or is the fact that it's only in games more indicative of maybe the audio read with the BluRay laser getting corrupted at some point within the console? Any help and suggestions would be much appreciated!

Thanks!