PHILIPS 25TR19C225
Manual de Servicio

voltage, and +5 volts. The EHTINFO line is the DAG line. This line is fed back to the Signal Processor IC, 7250, to adjust the Picture level to compensate for changes in Beam Current. The EHTINFO line is also connected to resistor 3478 and zener diode 6480. If this line should go excessively negative, which would be caused by excessive Beam Current, transistor 7481 will turn On. This will place a High on the P9STBYON_PROT line shutting the set Off. The Filament voltage is monitored for no voltage or excessive voltage. The Filament voltage is rectified by 6463 and fed to the base of transistor 7462. If the voltage on the base of 7462 goes above 6.8 volts, 7462 will turn On, turning 7463 On. This

will place a High on the HEW_PROT line. This will shut the Horizontal drive Off. The EW_DRIVE from the Signal Processor drives transistor 7470 to make linearity corrections in the Horizontal Drive. If Horizontal drive should fail, the source leg of 7470 will go High, placing a High on the P9STBYON_PROT line shutting the set down. MICROPROCESSOR SWITCHING 6) (Figure

In the Standby mode, Pin 19 of the Microprocessor, 7600, is held Low by a switching circuit inside the IC. When Set is turned On, this circuit switches

FIGURE 6 - MICROPROCESSOR

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