According to the fault analysis, may be due to reasons such as circuit radiation produced by parasitic oscillation is line in the sawtooth wave modulation. This machine is of high voltage circuit and separate line scan circuit, made little impact on each other, is good for high pressure stability. Under the way of horizontal frequency of 60.2 kHz, line scan measuring tube Q550 sc5407 (2) c voltage of 85.1 V, normal. The downstream damping tubes D550 detection, no exception. This machine use leadtek PX7800GTX display card, the host after boot into Windows. XP setup procedure, first to block 1280 x800 signals, the display screen, there are still interfere with the tape. 7Chservice manual download site
 7Chservice manual download site
 7Chservice manual download site
As is shown above, with an oscilloscope measurement IC671 (TVSA0195) (1) foot line frequency pulse output, size, and presence of burr phenomena, and to observe its amplitude results is normal. Remove the Q601, D602 and C601 and D603 components, using transistor tracer or universal bridge inspection, found that poor D603, replace D603 (after high frequency diode), troubleshooting.7Chservice manual download site