Iiyama Vision Master Pro 454 HM903DT Service Manual page 31

4-5. DYNAMIC BEAM FOCUS (DBF) circuit
(1) H-DBF
The parabolic wave of horizontal period is output from pin 9 of IC350 (HDFO) and then amplified b y
Q516 and Q517. It increases up to approx. 500Vp-p by T503 and synthesized with V-parabolic
wave and then applied to pin 13 (DF) of T501 (FBT).
(2) V-DBF
The parabolic wave of vertical period is output from pin 8 of IC350 (VDFO) and then amplified by
Q520. It is synthesized with H-parabolic wave.
- 26 -
CRT cathode input
(H period)
T501 (FBT) pin 13 input
DBF horizontal element
(100V/div)
CRT cathode input
(V period)
T501 (FBT) pin 13 input
(200V/div)