Date: 201605
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: VHF
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Diverted; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Prior to closing the boarding door the A F/A asked us if we needed anything for departure. The Captain asked for a couple of cans of water. The load manifest was handed up to us and I began programming the OPC and FMC. As the waters were handed up to the Captain; one fell on the center pedestal and the can burst splashing water over all of the center pedestal panels. The Captain and I immediately started cleaning up the spill and we attempted to call Maintenance. We noticed that the Captain audio select panel would not select radios as normal; so I called Maintenance over the number two radio using my audio select panel. Maintenance Personnel came out and started by removing the Captain's audio select panel. A large amount of water came out of the unit and they called to replace it. In all; they removed each unit in the center pedestal and replaced many of them with new units. They tested the function of all panels and restored the aircraft into service. After Maintenance left; the Captain and I started all of our preflight system tests and everything seemed in working order. We ran the appropriate checklists and departed normally. During cruise we started to smell an odor; but were unable to identify it. We discussed that the Maintenance Technicians had used a spray cleaner to remove water from the connectors and that we may have been smelling a residual of that. After a few minutes the odor seemed to be dissipating; so we elected to press on; but decided that if we were to smell it again; we would take appropriate actions. Within a minute or two of that discussion I noticed visible smoke coming from my audio select panel. We donned our oxygen masks and [advised ATC]. After a short discussion; we elected to divert to [a nearby alternate]. The Captain then completed the QRC and QRH. The F/A's were notified of the descent and diversion. The Descent and Approach Checklists were completed and the aircraft landed normally. Upon exiting the runway; we noted that the audio select panel was no longer actively smoking and we decided to continue to a gate. Once at the gate the oxygen masks were removed and the shutdown check was completed. At that point the panel began smoking again. The Captain exited the flight deck to announce to the F/A's to expedite the egress through the forward boarding door. I immediately called Maintenance over the phone to find the appropriate circuit breakers to remove power from the audio select panel. Once the passengers were off the aircraft; power was removed from the aircraft.ATC had CFR standing by when we landed; and they met us at the gate and after deplaning an inspection by the Firefighters was completed. I then completed a walkaround inspection of the aircraft and returned to the jet bridge to discuss the issue with the Crew. The F/A's stated that [no one was] injured in the event. Both the Captain and I thought that the spill was cleaned up and that all affected panels had been replaced or addressed. Everything seemed to be in normal working order during all systems test prior to departure.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B737-800 flight crew reported diverting to a nearby alternate after the #2 radio began smoking in flight. A pre-departure water spill on the center console appeared to be the cause.