Motorola 50-X-1 Pre 1941 Art Deco style table radio.
The Motorola 50-X-1 manufactured by the Galvin Manufacturing Company is listed as a Broadcast Band (AM), pre 1941 radio by NostalgiaAir.org (see Links page), Riders volume 12 pp 26, 35-36. It is a five tube AA5 (All American Five) radio with the following Tube Line-up:12SA7, 12SK7, 12SQ7,50L6 and 35Z5. It has an Electro Dynamic (no permanent magnet) speaker.
The case is made of Bakelite with an Art Dec styling to the speaker grill, dial face and knobs. This particular case is in great condition with no cracks. It has only a scratch on one side that darkened with treatment. Once cleaned and conditioned the rich dark brown of the Bakelite shows its vintage with a very slight marbling/swirl effect. The dial lamp (new) illuminates the dial scale and casts a soothing glow onto the table in front of the radio.
Circuit restoration was quite straight forward. Most of the resistors (all were replaced) were way out of tolerance and all wax/paper and electrolytic capacitors were replaced. The unit required three UL rated safety capacitors (15, 17 &18). Two in the circuit and one for the external antenna lead. Capacitor 17 from the circuit common to chassis ground keeps the unit from self oscillation and receiving birdies at the band end. The two section electrolytic filter capacitor was replaced by discrete capacitors on an additional terminal strip. The terminal strip, being solder mounted to the chassis, provided a convenient place to attach C-17 from ground to chassis. One of the five tubes 50L5 tested bad with a short circuit with in and was replaced.
Schematic at http://www.nostalgiaair.org/Resources/623/M0006623.htm.
Once restored and aligned the radio is sensitive and plays well across the whole broadcast band. Band coverage is from 1720 to 530 K cycles.
To properly restore, clean, polish, treat, align and test this radio it took approximately five (5) hours of labor. It was "burned -in" for 24 hours (one hour prior to alignment). Every component was verified against the schematic for proper value and circuit connection. There were some wrong value components installed during a previous servicing (this is unfortunately typical of radios of old vintage) and a shorted audio tube.
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