Occurred twice in my case on 2 different 732s - both during
the SEA wet.
Snap! Me too in a 737-200 at night out of Taipei for Guam with a typhoon spinning across our planned track 400 miles to east of Taipei. In cloud and swore the radar was picking up reflections from stormy seas but no CB which seemed unusual. Then without warning violent turbulence and usual St Elmo's and all that stuff still in cloud. Checked radar gain and tilt and saw expected flecks from the sea but in fact the radar was inoperative and probably had been so after leaving Taipei. But the screen looked alive.
Resorted to face pinned to windscreen watching for cloud gaps illuminated by between lightning flashes. Then we would weave between tops. Copped it for 10 minutes or so and finally cleared it.
Sorry about the war story...
