Product specifications

DA100 (50Hz) and DA50W Chassis – Repair Notes
Page 39 of 80
 Q503 turning off due to the removal of its gate bias.
 Q502 turns on because of D507 conducting and pulling its base voltage lower than its emitter.
Figure 36: Vertical Fly-back Circuit
From the junction of Q502 collector and the scan coils the vertical fly-back pulse is applied to IC801 pin 11
(Vprot Signal). This is an indication that the vertical output stage is operational. If IC801 cannot detect the
negative edge of this pulse then IC801 will presume that the vertical stage is not operating correctly and blank
the RGB drive.
Figure 37: Vertical Protection Signal (VPROT - Pin 11 of IC801)
Sharp Electronics (UK) Limited - May 2003
Revision 3