Cabinet Front of the 1939 Sentinel 160BL, cleaned up and working.

Sentinel 160BL Restoration – Part I

This little old radio was given to me by a good ham radio friend of mine. It was excess to his needs and he called it a challenge: what can you do to improve this ugly old radio. And it was an Ugly Duckling, in very rough shape. As a portable, how many beaches had it visited? It was used so much the handle is gone! How many vacations or garages had it provided radio?

It’s a Reflex

Some research turns up that this is a nice example of a very simple Reflex radio. The first Tube, a 1A7G, tunes the signal. This is fed to the 1N5G which amplifies the IF signal. Note that the Volume Control wiper sends the incoming IF back to the input of the 1N5G.

Eventually a signal exits the 2nd IF Transformer to the Diode Plate of the 1N6G where the AM is Detected. The rest of the tube is an Amplifier for the Speaker. Each stage does double-duty!

Also, a simple AVC is provided via the Audio Transformer which, using the Screen Grid of the 1N6G, controls volume.

Tuning dial is yellowed but clear.
Tuning dial is yellowed but clear.

Together, with the three tubes (and the 1N6G is basically 1A5G with an added diode), the current draw is only 150 ma for filament and just under 7 ma at 90 volts plate.

The Sentinel 160BL was also sold as the Aria, in the Allied Stores in New York.
The Sentinel 160BL was also sold as the Aria, in the Allied Stores in New York.

This radio was marketed under Sentinel’s own brand, and also as an “Aria” branded radio, which was a department store brand. “Aria” was sold in Allied Stores of New York (ref: from ‘radioremembered.org’, “ALLIED STORES (private brand Aria), 1440 Broadway, New York, N. Y.”).

The 1939 components were very nearly all out of tolerance. There are only one or two 'original' parts left underneath.
The 1939 components were very nearly all out of tolerance. There are only one or two ‘original’ parts left underneath.
Detail of the Tuning Capacitor, oscillator coil, and 1A7G tube.
Detail of the Tuning Capacitor, oscillator coil, and 1A7G tube.

Completed So Far

  • Inspected and cleaned.
  • Some of the wicker-covering was peeling; some glue repaired this.
  • Cabinet blocking inside was loose – glued to reinforce.
  • Missing Handle – Replaced with a not-quite-Repro quality (but functional) leather strap.
  • Replaced resistors and capacitors as needed, testing for significant out-of-tolerance.
  • Aligned, per the “Rider’s Perpetual, Volume 11 (1940 and before)”.

It’s a swell little AM Broadcast receiver now, and runs under test power.

But what to do about portable power options?

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