[old_tv_nut]

Not following what 147 v waveform you are referring to. According to the schematic, pin 1 of V21 (V21a plate) should be at 115 v dc. Since it is coupled to the color difference amplifier cathodes by C 135, it should have the same peak to peak ac waveform as those cathodes, which the schematic shows as 15 volts peak to peak. The 12 v p-p you measure is very reasonable and the total p-p will depend also on the amount of color in the image as well as the setting of the color level control. With the color turned all the way down, you should see just the blanking pulse, which by itself appears to be 10 or 12 v p-p.