JVC Model 200 service manual Horizontal/Vertical Deflection PCB

Chapter 2---System Description

2.3.8 Horizontal/Vertical Deflection PCB

The HVD board is located on the top side of the deflection cage in front of the electronic card cage.

The Horizontal/Vertical Deflection Board I/O diagram (Figure 2-14) and the list of inputs and outputs (Tables 2-10 and 2-11) provide information for the technician to perform module level troubleshooting.

The following functions are provided by the HVD board:

•Horizontal raster centering for all three colors

•Horizontal gate drive

•Switch mode power supply generating the required proportional DC supply

•Horizontal width adjustment

•Horizontal retrace switch network

•Left/right pincushion and keystone correction

•Drive main deflection coils to provide horizontal raster scan for all three CRTs

•Drive main vertical coils to provide vertical raster scan for all three CRTs

•Vertical linearity adjustments individually for all three colors.

•Vertical raster centering for all three colors

•IIC interface

IIC Interface

All adjustments for the HVD board are performed by the System Controller via the IIC serial bus interface. This three wire bus interface consists of a clock line, a data line, and an interrupt line. The HVD board does not create any interrupt and the interrupt line is not used for this application. Table 2-10 lists the adjustments executed via the IIC bus interface (I = Input to HVD board , O = Output from HVD board):

Model 200 Service Manual 2-45