Horizontal Deflection - Philips 29PT6441/85 Service Manual

There is a current source inside the UOC at pin 102. This pumps energy in the capacitor
connected to this pin producing a pure saw tooth. The vertical drive signals and the E/W
correction signal are derived.
Pin 108 is the East-West drive (or AVL), and it is a single ended current output. The
correction for "horizontal width for changed EHT" from this pin is available by setting the
HCO bit to "1".
The Phase-2 Compensation available at pin 113 gives frame correction for high beam
currents. The phase compensation signal is used to correct the phase of the picture
from the horizontal drive signal.
Pin 63 is the SANDCASTLE output (contains all sync info) and also HORIZONTAL
FLYBACK (HFB) input.
Pin 97 is the EHT tracking/over-voltage protection pin. The HCO bit can switch on the
tracking on EW. If the voltage at pin 97 exceeds 3.9 V, the over-voltage protection will
be activated and the horizontal drive is switched "off" via a slow stop.

Horizontal Deflection

There are several executions (depending on the CRT):
Sets with no East-West correction. The principle of the horizontal deflection is
•
based on the quasi-diode modulation circuit. This horizontal deflection circuit
supplies the deflection current and auxiliary voltages from the LOT.
Sets with East-West correction. The principle of the horizontal deflection is based
•
on a diode modulator with east-west correction. This horizontal deflection circuit
supplies the deflection current and auxiliary voltages from the LOT.
Sets with dynamic East-West correction. The principle of the horizontal deflection
•
is based on a diode modulator with dynamic east-west correction for picture
tubes with inner pincushion. This horizontal deflection circuit supplies the
deflection current and auxiliary voltages from the LOT.