The side view of the linear shows the 4CX250B's mounted horrzontalfy with the blower fastened to the back of the cabinet.
If the current is too low or negative reduce loading. This current should not be exceeded if it is too high, increase loading. The screen current is 50 to 60 ma at 350 volts. When the amplifier is properly loaded, cathode current is about 550 ma at 2000 volts. The screen and cathode currents are read with the flip of the meter switch. It is supported by three steatite stand-offs one inch long. The filaments and blower are designed to be switched on at least three minutes before the plate supply is energized, the neutralizing capacitor is a piece of brass Hat stock V by 7" mounted away from the plates of the final tubes. I used six volt solenoids since they were cheaper than twelve. Phase A leg will not supply any voltage without one of the other legs connected. They complete the circuit of phase B-C to the transformer.
Te high voltage supply is switched into action by energizing two six volt auto started solenoids connected in series. Each of the 750 volt outputs is shunted by a 50 k, 20 watt resistor that acts as a voltage equalizer and bleeder. You probably could use 100 \xf electrolytics with slightly poorer regulation. The amplifier was neutralized to improve its stability, but this turned out to be unnecessary. II your exciter output is less than 65 watts PEP, you probably will need a tuned input. I didn't use on L network in the cathode circuit of the linear. If you want to, you'll have to use larger pi network capacitors or switch in some extra capacitance on this band. You've probably noticed from the schematic that I didn't include eighty meters in the linear. An exciter with 65 watts output will drive the pants off this linear on all bands-even ten. Drive required is higher than class AH, but less than grounded grid. As in true grounded grid, about 8035 of the drive shows up in the output. The 1CX250B tube is not suitable for regular grounded grid operation (that is? with the control and screen grids both grounded), for screen and grid currents will run too high and ruin the tube, But they work fine as tetrodes with drive applied to the cathode, the grid grounded and the screen at about 350 volts.
#Tuner in bias amp 2 tv
The diodes are standard TV replacement types. The 115 voll winding becomes the bias source. There are many similar ones available from the surplus dealers who advertise in 73.Ī small replacement transformer rated at 350 volts each side of center at 50 ma, 6-3 v at 4 amp and with a 1)5 v primary is used to furnish bias and screen voltages, The 6,3 volt winding becomes the primary and is connected to phase A at the center tap point of this transformer. This voltage and current is maintained with a charging voltage of 14 volts from the alternator.
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