The S - 27 is a hollow state receiver covering the VHF range. The set developed around 1940 covers the 27 - 145 MHz frequency range, the later S - 27B version covers the 36 - 165 MHz frequency range.

The receiver comes in a rugged metal case with a hinged lid giving you access to the chassis to exchange the valves, it's dimensions are 48,3 x 23 x 25,6 cm and it's weight around 20 kg.

On the left side of the front panel, you find the rotating backlit main frequency dial, in contrast to the metal disc dials on older Hallicrafters models, only a part of the dial is visible behind the dial window. In the left lower corner of the frequency dial, you find the three position bandswitch. This lets you select one of three frequency ranges (27,8 - 47 / 46 - 82 / 82 - 143 MHz).
Just below, you find the R.F. gain control, the antenna trimmer, a bandwidth control (SHARP - BROAD) which also acts as mains switch and the A.F. gain / volume control at the right.

At the right of the main tuning dial, you find the fine tuning dial, which is mechanically coupled to the main tuning and is operated with the the typical Hallicrafters "steering wheel" tuning knob, below you find the switches for ANL (which activates automatic noise limiter), the AM / FM mode control, below the BFO switch and at the right the BFO pitch control used for single sideband and CW reception.
At the right, below the signal strength meter, you find the tone control and at the right the Send / Receive switch (to mute the receiver when used in connection to a transmitter) and the headphones jack. A high impedance speaker (5000 Ohms) can be connected at connectors at the rear of the receiver, to drive an 8 Ohms speaker, you need a matching transformer.

When You have managed to apply the correct power to the receiver, it's operation scheme is different in AM and in FM mode.
Use the selectivity control to turn the radio on (yes - that's typical Hallicrafters, not to combine the mains switch with the volume control), turn the R.F. gain to the maximum setting clockwise and the A.F. gain somewhere in a middle position and select the frequency band. The AVC should be activated (switch to the left) and the BFO should be turned off, make sure, the SEND/RECEIVE switch is in the RECeive position.