| Sharp | SV287XH | Blank raster/no sound - OSD present (RF & Scart) | Switching [video and audio] is performed by IC401 [M51321P] a three gang three way device. pin 15 of the IC works on a tristate level. With the IC supply being 12V: 0 - 2.5V Input from BNC; 5 - 7V Input from scart ;9 - 12V Input from tuner. Diode D419 [DX00458M] which links to the wiper of the AGC preset was leaky, limiting the voltage on pin 15 to 7V and thus preventing tuner mode selection. Replace D419 with an IN4148 | 14-09-04 |