I had the same experience this summer with my four year old ICOM IC-M504 VHF transceiver. Under the advice from Hamilton Marine, I sent mine in to Williams Communications, Inc. in Tallahassee, FL (likely the same ICOM regional repair facility used by the OP). ICOM had a bad batch of RF filters in these radios - the repair was free, even though the unit was out of warranty. All it cost was one-way shipping to Florida. What a pleasant surprise!!