Stewart-Warner Model 91-531 Tombstone Radio (1938)

  

A charming smaller tombstone with exceptionally pretty veneer, this radio was well cared for. The cabinet looked almost like new when I found it. In a Ziploc bag tucked inside the back, I also found the original owner's manual plus copies of the Rider's service sheets.

This radio is considerably smaller than my full-sized GE S-22X Tombstone. It also has a very different look. The GE is large, dark, and ornate; it would not look out of place next to most 1920s radios. This Stewart-Warner is streamlined, gently rounding at top of the cabinet and horizontal grille louvers. It look more like a 1940s radio, although it was made only four years later ((1938) than the GE set (1934).

The round knobs are original and they are molded with a graceful S/W logo. Surrounding the dial and pusbuttons are two decorative escutcheons with raised lines of lacquered brass on a black background.

This radio receives the usual BC (AM) band from 540-1725 Khz and shortwave broadcasts from 5.4-15.4 Mhz. Below the tuning dial are several pushbuttons. The leftmost button, labeled Speech, is a tone control. When the Speech button is pushed in, it accentuates the treble, making speech more audible. When pulled out, it accentuates the bass.

The rightmost button, labeled Foreign, selects the shortwave band. Next to it is the Broadcast button, which both selects AM reception and allows you to set the five preset tuning buttons.

As in my Zenith 12-A-471 and Crosley 146CS, the preset tuners work electronically rather than with mechanical gizmos that drive the tuning capacitor. Setting them requires removing the lower escutcheon to expose the adjustment screws.

To set an individual button, you push in the Broadcast button and tune the desired station as usual. Each button has a predefined frequency range (for example, 550-1000 Khz), so you must choose a station within that button's range. Then you push in the chosen button and adjust its two trimmer screws until you receive the station clearly with maximum volume.

The radio originally came with a sheet of pre-printed call letters, which you could insert in the button's face once you set it to that station. I suppose the sheet of extra call letters was the first thing that most owners discarded. In any case, I have never found a radio that included this bit of ephemera.

Inside the cabinet is Stewart-Warner chassis number 91-53, a conventional five-tube superheterodyne receiver. This chassis was used in models 91-531 to 91-539, according to the Rider's sheet. The other models probably housed the same chassis in different style cabinets. Here's the tube lineup:

Tube Type Function
V1 6A8G 1st detector/oscillator
V2 6K7 IF amplifier
V3 6Q7G 2nd detector/AVC/AF amplifier
V4 6K6G Audio output
V5 5W4G Power rectifier

Restoration Notes

Restoring the cabinet finish took only a few minutes. After removing the chassis and hardware, I cleaned the cabinet with paint thinner and a soft cloth. Then I wiped on a coat of Minwax Special Walnut finish. After letting the Minwax set for about two minutes, I rubbed it off again, then vigorously buffed the whole cabinet with a clean, dry cloth.

This treatment darkened any little scratches on the cabinet, making them blend in almost invisibly, without otherwise changing the finish, other than to impart a nice shine. If you left the Minwax on for a longer time, or didn't rub it off so aggressively, it would darken the original finish, of course. The trick to this technique is that you remove almost all of the Minwax, except for what's left behind in the scratches.

I haven't had time to delve into the electronics yet. Repairing it should be no more difficult than fixing any other "All American Five" radio. It was obviously serviced at some time in the past. Two or three of the old paper capacitors were replaced with plastic "Black Beauty" capacitors. Unfortunately, those early plastic capacitors were just as unreliable as the paper ones which they replaced! You can read more about capacitors in Replacing Capacitors in Old Radios.

Other tombstones in my collection include a 1937 Philco 37-61, a 1937 Zenith 6-J-230, and the GE S-22X mentioned earlier.

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