CRJ700 First Officer reports a loud pop during climb followed quickly by EICAS messages for gear disagree; WOW caution; and PSEU caution. The smell of melting rubber is also present in the cockpit and the cabin. An emergency is declared and the crew diverts to the nearest suitable airport.

Narrative

While climbing to cruise altitude; I heard a loud pop. EICAS messages (Gear Disagree Warning; WOW [weight on wheels] Input Caution; WOW Output Caution and PSEU [Proximity Sensing Electronic Unit] Caution) immediately appeared along with the Master Warning. An odor of melting rubber enveloped the flight deck shortly after the loud pop. I called for the QRH to perform the procedures for Gear Disagree warning and cautions. The Captain contacted ATC declaring an emergency requesting closest airport in case of fire; and we descended to the airport. The Captain informed the flight attendants (who also heard the loud pop and could also smell an odor of burning rubber) and passengers of the situation and we diverted to the airport. The Captain landed the aircraft on the runway. Fire rescue checked the aircraft on the runway for damage; and the Captain taxied the aircraft to the gate area. Company operations and maintenance was contacted. Maintenance came out to the aircraft. PSEU channel A circuit breaker was discovered out while the aircraft was at the gate with engines shut down.