Came out today to diagnose a Mitsubishi mini split not operating. Upon arrival I called tech support. While on hold I took a look at the condenser and found that the microchip attached to the board has a lot of white corrosion on it. While on the phone with tech support they had me check multiple items on the system. We found a bad control board part #K9709369012, compressor part #K9332603002, a bad fan motor part #K9603074036, and a bad expansion valve coil part #K9970103025. Tech support did say that the parts are covered under warranty but not the labor. Chud will have to decide to either replace just the parts or change out the whole condenser.