The common of the power supply connects to circuit ground. The negative, zero to minus 100 volts, output goes to the top of a pot and the bottom goes to ground. The wiper of the pot goes to the control grid of the tube being tested. There is a voltmeter connected from the grid to ground. The cathode and suppressor grid are grounded. The screen goes to the positive output of the power supply. The plate goes through a milli amp meter to the positive output of the power supply. The tube heater is energized from the 6.3 VAC output of the power supply. End verbal description.
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