Help Quad 989

Thanks first for your help. One of my 989 is making some hissing noise from the upper-right corner of the lower panel! The noise sounds like white noise, but not very audible. I can only hear it within 2 feet. Is this caused by humidity (these days the humidity of metro Boston area is very high, around 80% or so). Anyone has faced this situation??
I believe what you have is a speck of dust between the diaphragm and stator, and it is being burned away. The hissing should go away with time. If you would like a more qualified second opinion, contact Ben Openshaw, aka The Electrostatic Doctor, at (208) 535-1302.
Quads are marvelous speakers but hate humidity.
After repair,Install a deshumidifier in your audio room.