Yaesu Musen FLDX400 Transmitter General Front Panel View

The FLDX400 is a hybrid valve/transistor design to cover all of the pre WARC HF amateur bands 80m, 40m, 20m,15m,10m. The unit is designed to operate as a stand alone unit or in conjunction with the matching FRDX 400 receiver.
The VFO is solid state design covering a 600 KHz segment with a linear analogue dial calibrated in 1KHz steps.
Single sideband generation is achieved with a diode ring balanced modulator and a 455 KHz mechanical filter. The IF is up converted to a fixed IF of 9MHz. The band switched up convertor is mixed with the 9 MHz IFsignal and finally the VFO is mixered to generate the wanted transmitter signal. The transmitter uses a pair of 6JS6C valves to give 240 Watts output power. An analogue meter is switchable to monitor the P.A. current, output power,or ALC voltage.