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The output of the amplifier is a Pi-L circuit. The ceramic capacitor for TUNE and LOAD are
divided. This enables the amplifier to be tuned exactly and makes it possible to easily return to
the previously set positions after band changes.
Top view on the opened OM4000A
Tetrode FU728F
PWR Meter
Blower
Switch-ON Board
Output Pi-L Circuit Tuning Capacitor
Subpanel
Power Supply Board
3.2.
Power Supply
ower supply of the amplifier is comprised of two of 3 kVA toroidal transformers. A soft
start is provided using relays and resistors.
The high anode voltage is made by combining 8 x 420 V (total 3360V) @ 2.5A. Each has its own
rectifier and filter. In the high voltage circuit, safety resistors are employed to protect the
amplifier against overload.
The source for screen grid is regulated by parallel stabilization with BU941 NPN Darlington
transistors and delivers a voltage of 350V at 200mA. The -120V for the control grid is regulated
with Zener
diodes.
P
Summary of Contents for X8NOM4000A
Page 28: ...Page 28 from 38 7 1 ...
Page 29: ...Page 29 from 38 7 2 Example of connection for ELECRAFT ...
Page 30: ...Page 30 from 38 7 3 Example of connection with Yeasu ...
Page 31: ...Page 31 from 38 7 4 Example of connection with antenna switch and BPF ...
Page 32: ...Page 32 from 38 7 5 Example of connection USB micro KEYER II with IC7800 or IC7700 ...
Page 33: ...Page 33 from 38 7 6 Example of connection USB micro KEYER II with another Icom ...
Page 34: ...Page 34 from 38 7 7 Example for connection USB micro KEYER II with Yeasu or ELECRAFT ...
Page 35: ...Page 35 from 38 7 8 Example of connection PA with MicroHAM MKII MK2R etc with CI V output ...
