B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
The airplane had significant Mx done in ZZZ. Due to the maintenance done in ZZZ; there were several items that needed to be accomplished in flight; such as a CATII/III autoland; APU cold soak; and verification flight. The captain flying the aircraft from ZZZ to ZZZ1 signed off the autoland and verification flight; but couldn't sign off the APU for the short flight; although the APU worked fine. He did encounter the following anomaly: a status message on departure of 'FO INSTR XFER'. (This only popped up for a second and went away. Also; the Autothrotles disconnected once during the climb; when the status message occurred.) Mx was made aware of all of this. The first officer's EADI/EHSI both blinked when this occurred.Fast forward to our flight: ZZZ1-ZZZ2. The first officer's ADI/HSI blanked out 2-3 times during takeoff and climbout. There was no status message that accompanied this. However; we did receive 2 separate status messages of the FO INSTR XFER; that disappeared within 1.5 hours of the flight. Approximately 5.5 hours after blockout; the R GEN OFF light illuminated; tripping the utility buses off; which also turned both Recirc fans off. The crew accomplished the non normal checklist; including starting the APU; and although we were unable to restore the R GEN; we continued the flight with 2 sources of power- the L GEN and the APU. The rest of the flight was uneventful.Our crew believes the incidents on both flights were related; and that the blanking of the first officer's screens/ FO INSTR XFER were related to problems from the right generator. (maybe moisture got in the engine/generator while on the ground in ZZZ.)Suggestions: We recognize that hangar space is a premium; however; ZZZ is notorious for summer rain showers/thunderstorms. Extra caution should be taken when parking aircraft there AND performing maintenance; especially heavy maintenance. In addition; it would behoove everyone if engines runs were performed after work is done on the engines; generators; and APUs. Or utilize the resident expertise at the training center and perform test flights. (this gives the instructors some actual flight time; while in ZZZ; and maintenance can troubleshoot better.) just a thought. otherwise; our inflight mechanic was suggesting false paths for the problem we had; like maybe a bad Symbol Generator; and asking us to swap EFIS switches during the flight.
B767-300ER reported an uneventful flight after completing QRH procedures for loss of right generator.