Does anyone else have a high-pitched (but line frequency modulated) noise coming from their HP 3478A when turned on? I listened around when I had it apart to change the battery, but I couldn't spot it. I tried using a piece of plastic tubing as an improvised stethoscope, but couldn't narrow it down to a single component. It's somewhere near the transformer though.
It still works perfectly and has a 5 year old calibration, but it annoys me a bit, having sensitive ears.