JVC Model 200 service manual Video Processor PCB

Chapter 2---System Description

2.3.4 Video Processor PCB

The Video Processor Board (VPB) is the bottom-most card (see Figure 5-1) in the card cage. It is connected directly to the Backplane board through 2 connectors. When an external signal is being received, the VPB provides Horizontal Sync, Vertical Sync, and Green Sync signals to the Raster Timing Generator (RTG) board. It also provides three primary color signals, and G2, G1 bias and DC RESTORE control signals to the Video Amplifier Board (VAB).

The following functions are provided by the VPB:

•Video signal input and multiplexing

•Sync signal stripping

•Overlay signal multiplexing

•Brightness and Contrast control, and DC RESTORE

•Video signal gamma correction

•Sensitivity and Threshold signal input and control

•Automatic limiting for Contrast, G2, and internal video

The Video Processor I/O diagram and the list of inputs and outputs provide information to allow the technician to perform module-level troubleshooting.

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