The above link is to the sound my cirqus Voltaire makes from both speakers when quiet.
It developed after a the visual audio board failed / fixed but it had been in storage for some years before this.
This sound has become slightly louder over the last month and for anyone with (sensitive) hearing it is annoying.
My other machines former and present did not have this issue and they have all been bally Williams 90s.
It is like the sound the LCD display board makes when in use... but louder.
I've also noticed that the game volume is unusually loud. Even on vol 1 it is too loud for quiet play.
Though the sound quality and music is excellent with no pops or crackle or reverb of any kind.
I think I have checked everything in the head box. I have tightened screws and tried the audio visual board separate from the unit. I've removed every board, cleaned them and put them back with all wires. No broken wires or eprom pins out of place.
If I unplug the speaker cable it goes away as does the sound.
There are no sound or music issues in the diagnostics. Google has a few posts but nothing I could use. Kindly strangers have mentioned grounding but this is a mystery to me.
I am a beginner so this issue is currently beyond my expertise but a problem. If someone can advise and detail any tests I could perform if nec., bearing in mind I am not experienced (yet and only have simple tools.
Thank you for taking the time to read my post.