3CPX1500A7 Amplifier      
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Control Chassis






Plate Circuit






3000 VDC 1 Amp Supply

Step Start
Power Supply Enclosure
8877 Pin Out Information

This Linear amp was built in 2003 and puts out 1500 Watts with 57 Watts of drive. It has two microcontrollers in the control loop. One provides a 3 minute delay for the High Voltage and the other a 3 second step start for the Filament. It is a single bander for 20 Meters and features a Pi-L output circuit and a tuned input circuit. Vacuum relays are standard and can be modified for QSK. It runs cool and based on the plenum size adequate cooling is provided without excessive blower noise.

In 2009 several upgrades and modifications were made to the amplifier and power supply. After having a problem with the 3CX1500A7 it was replaced with a 3CPX1500A7. A new 1N3307B Zener Diode was installed in lieu of the ECG equivalent and the two back to back meter protect diodes, originally 1N4007's were replaced with more robust 1N5408's. The step start in the power supply was changed over to a DC operated 110V coil and venting was installed over the capacitor bank. The amp is back on line and working as it should.