This was my first transmitter, which, along with the HQ-140-X, comprised my first station as a NOVICE WD8PCE in 1977. Sitting on top of the VFO is an accesory screen modulator for AM phone.
The WRL-90 tube lineup is straightforward, being a 6AG7 oscillator/buffer , a 5U4G rectifier, and a pair of 807s in parallel as the final amplifier. It has a maximum DC input power of about 90 watts. The 755-A VFO consists of a 6AU6 oscillator, 6CB6 buffer, and an 0A2 regulator. The VFO and the transmitter cover the traditional ham bands from 160 m to 10 m. The screen modulator has a 12AX7 speech amplifier and a 12AU7A modulator.