This topic reminded me of my own high pitched whine on my Commodore 1084S (not 1084S-D1) monitor back in the day, so I thought I should reply, to tell everyone what cured it, in case that helps.
I bought my Amiga A500 package from Silica Shop while my Dad was dying of Cancer in hospital. He never returned home. It came with both the Tenstar Games Pack (including Barbarian by Palace, Mercenary, Insanity Fight, Amegas, and Ikari Warriors) and Photon Paint. It was delivered in a van in some cardboard boxes marked ATARI! After setting it up, I noticed a high pitched noise coming from the monitor. I think this was going on all the time, but it wasn't that noticeable, almost ultrasonic and I just put up with it. The monitor also had one dead pixel.
Several months later, after my Dad died, I moved out of the family home into my first flat, because my Mum was planning to move to a very remote area, so I needed to get my own home in London or be assimilated, meaning lose my whole identity. This involved most of my belongings being loaded into a small van, then being driven from SE London to NE London. The flat was on the first floor, up a short flight of stairs.
After setting up my Amiga in my new flat, I discovered that the high pitched whine had permanently stopped!
Of course, there are no new Commodore 1084S monitors nowadays, but this might just help someone who owns one of these monitors which has a high pitched whine.
