That was the vertical sync circuitry gaining a new SED (smoke emitting diode).

pcworld.com is my reference.

Peter's right of course, but if you're used to an old CRT you'll be astounded at the improvement in quality of CRTs. Trintron CRTs can now easily do a vertical refresh of 100Hz at 1280x1024, with razor sharp convergence.

IBM's 17in Trinitron CRT is only about 250 bucks.