Problem- No raster 27D9200
Discovered- Usual suspects- Q413,414,418 - D424 - R462,854, & leaky C423 4.7/400V
Capped PS, checked solder, HOT, FBT and yoke. Replaced IC401,404.
Restored power, quick SNAP and shorted out all semiconductors replaced parts above.
Replaced same but left out Q418 restored power now good HV.
Scoped TP 17 for the 168V square wave, just steady state 170VDC.
Square wave from IC404 output good and at primary of T401 transformer but no sign of any secondary pulses. Found open D424 checked good in circuit because of internal diode in FET Q414, replaced. All components test good on secondary side still no waveform.
If I return Q418 all components will short out, again.
Q418 has proper frequency and drive signal as shown on TP 15
Tried a good yoke and flyback , T403, 402, 401 all ring good, same bad results.
Ideas?
Discovered- Usual suspects- Q413,414,418 - D424 - R462,854, & leaky C423 4.7/400V
Capped PS, checked solder, HOT, FBT and yoke. Replaced IC401,404.
Restored power, quick SNAP and shorted out all semiconductors replaced parts above.
Replaced same but left out Q418 restored power now good HV.
Scoped TP 17 for the 168V square wave, just steady state 170VDC.
Square wave from IC404 output good and at primary of T401 transformer but no sign of any secondary pulses. Found open D424 checked good in circuit because of internal diode in FET Q414, replaced. All components test good on secondary side still no waveform.
If I return Q418 all components will short out, again.
Q418 has proper frequency and drive signal as shown on TP 15
Tried a good yoke and flyback , T403, 402, 401 all ring good, same bad results.
Ideas?