The Sony ICF-5900W has a similar exteral appearence as the Sony "Captain" receivers, it measures 22 x 23 x 10 cm and has a weight of 2,2 kg, so it's slightly more voluminous then the "little sisters".
The receiver can be powered from three 1,5V UM-1 batteries or from an external AC-456C mains power supply.

The frontpanel layout is slightly unconventional, but similar to the Captain 77: In the middle of the upper part of the front panel, You find a vertically moved film dial, the receiver covers three shortwave bands, and in these, the dial marks with 25 kHz spacing are not only simple dial marks but You need them to calibrate the finte tuning / interpolation dial.
The main tuning knob is the one located at the right of the frequeny dial. The big knob below the dial is the fine tuning knob, with the linear +/- 125 kHz interpolation dial; the bandswitch is located just at the right hand.
At the left of the frequency dial, You find the switch for the 250 kHz crystal marker, below the signal strength meter that also can be switched to act as battery strength indicator.

At the left hand, You find the separate controls for bass and treble and the volume control, nect to it the main switch, the attenuator switch DX and local and the BFO switch.

The telescopic antenna pops out of the cabinet when the antenna release lever is pushed, pull it completely out. As an alternative, You can connect a long wire antenna and earth to the screw terminals at the back of the receiver.
Use the POWER switch to turn on the receiver and set the volume control until a slight hiss can be heard from the speaker. The sensitivity switch should be in the DX position and the BFO switched off. Use the bandswitch to select SW1 for the 49 m broadcast band und use the main tuning knob to search for stations in the 49 m band.
To tune in to a station on a known frequency, You set the main tuning control to the next calibration mark, activate the crystal marker and tune for zero beat, then set the difference from the desired frequency to the calibration markt frequency on the interpolation dial. For example to tune in to the signal of Radio Deutsche Welle from Cologne on 6075 kHz, set the BAND SPREAD DIAL to zero, activate the crystal marker and tune to zero beat, i.e. until the whistle in the region of the 6 kHz calibration mark has disappeared. Then turn the BAND SPREAD DIAL knob slowly in the middle between the 70 and 80 kHz mark, now You should hear the signal coming from Germany. In the same way, You have to tune for some frequencies downwards from the calibration mark and substract the kHz from the calibration mark frequency. E.g. to tune in to 6220 kHz, use the main tuning knob to set the receiver to 6.25 MHz and tune for zero beat with the crystal marker activated, then turn the BANDSPREAD DIAL to - 30 kHz and You will ariive at 6250 - 30 kHZ = 6220 kHz. For 15565 kHz, locate the 15,5 MHz calibration mark and tune to + 65 kHz on the bandspread / interpolation dial - now, 15500 kHz would be tuned with the BANDSPREAD DIAL knob in zero position.

The tuning procedure is slightly complicated with the ICF-5900W, but it's not too difficult to learn. Remember that when the ICF-5900W was new, it's frequency accuracy was excellent compared to many other receivers in it's price range where You just could guess the frequency, only the Barlow Wadley XCR-30 and maybe the Panasonic RF-2200 had a useful frequency accuracy.
The ICF-5900W will keep it's place in my collection as a milestone on the way to a small travel shortwave radio. It's technical concept is outdated, but it's still a pleasent set to listen to FM and mediumwaves and maybe a shortwave signal from time to time. To take on trips abroad, I would recommend a PLL synthesized radio as the ICF-7600D and it's successors which made tuning to a station on a known frequency extremely easy and offered far better performance.