Panasonic TH-42PX20U Service Update Information page 26

Figure 13
The SC Board consists of buffers and drivers used to generate the scan signals
to the panel. The buffers provide isolation between the D board and the drivers.
Connector SC20 provides the drive voltages (140V, 100V and 18V) as well as
the trigger signals to switch the FET transistors. The D board switches the FETs
on and off to create the distinctive scan signal. Each trigger signal switches a
drive FET creating a portion of the waveform. For example, applying the CPH
signal to the 140V FET creates the peak portion of the waveform, see figure 12.
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