Hughes JVC 220, Service Manual

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Chapter 2---System Description
Interlocks and protection:
Input
None
Outputs
and H_LOCK-: Used to shut down the switching power
supply of the horizontal deflection amplifier in the event of a loose
yoke or loose scan reverse connector. This prevents the power
supply section of the Horizontal/Vertical Deflection Board from
operating when 1 or more yoke connectors are disconnected.
/SWEEP_OK: Shuts down the video amplifiers in the event of
deflection failure (if DEFL_OK or /H_ENABLE are not present).
2.3.9 Convergence/Deflection PCB
The Convergence/Deflection Board is located on the bottom side
of the card cage under the Horizontal/Vertical Deflection Board.
This board drives the convergence coils of the projectors.
The following functions are provided by C/D Board:
•
Generation of various waveforms for the horizontal and vertical
axes
•
Height control
•
Generation of waveforms for dynamic focus
•
Various geometry correction functions for the horizontal and
vertical axes
•
Convergence output amplifiers for all colors and both
horizontal and vertical axes
•
Convergence enable and raster fill function
•
ILA
®
assembly driver circuitry with temperature compensation
•
Phase locked loop for ILA
®
assembly drivers
•
IIC serial bus interface
The Convergence/Deflection Input/Output diagram (Figure 2-15)
and the list of inputs and outputs (Tables 2-16 and 2-17) provide
information for the technician to perform module level
troubleshooting.
2-48 Model 220 Service Manual