MiniDV Prosumer Camcorder.
It is an unfortunate flaw in a great camera, but the microphones in the TRV900 fail all too often. The cause is contamination by a silicone oil used liberally on plastic and rubber parts in the microphone housings. Using genuine Sony replacement parts, I first clean all the contaminated parts with a soap and water wash (as recommended by the silicone oil manufacturers), trim the rubber microphone bushings to eliminate thin films of rubber left from the original molding process, and replace the microphone assemblies with new Sony parts. I follow up with a sound separation test using a test stand and moving sound source. Here are some dead factory microphones and an oily mic holder with overmolding filaments.
Cost (including parts) is $129 US plus shipping. Please email for details on payment and shipping options.