Sony TV Repair. I've got a 32" Sony Trinitron TV, model KV-32XBR48. When the set is on, the video

Question

I've got a 32" Sony Trinitron TV, model KV-32XBR48. When the set is on, the video displays for like 2 seconds, then goes black for 2 seconds. Audio is fine. Sometimes the video will actually work for maybe 10 or 15 minutes, usually when the set is warmed up and has been on for 5-10 minutes. It's obviously an older set but I'd like to try and fix if reasonable. Any help would be very much appreciated. Thanks....