I’ve also encountered parts that do not appear on the manufacturer’s schematic diagram.  Judging from the solder joints, it’s clear that the radio was modified earlier.  Considering the age of the extra parts, it was probably modified in the late 1940s or 1950s.  Most of the non-original electronics are electrolytic capacitors, and based on where they were placed in the circuitry, I’m assuming that they were added to eliminate the “hum” that aging capacitors can cause with old radios, but that’s just a guess.

I wasn’t expecting a surprise from the vintage power cord, but as I removed some cloth insulation, it was clear that this cord was covered with felted asbestos.  This was common in the old days for power cords that were used for devices that made a lot of heat or used a lot of power, such as irons.  I disposed of any loose asbestos and cleaned the wiring.

Still have a lot of work ahead, but it’s fun and certainly an ongoing education.

Since this radio was modified several times over the years, with holes drilled in the case and chassis for non-original switches and sockets, it can’t be considered to be in ‘original’ condition.  However, that frees me to fill the holes, re-paint the case, and apply reproduction lettering to restore the case to a near-original appearance.

I have hours of soldering work ahead of me, but I’m in no rush.  I’m still waiting for the replacement tubes to arrive, and to maintain the proper vintage appearance, I’ve ordered new cloth-insulated 16 gauge wiring to replace some broken or cut wires.

Speaking of modifications, I’ve learned that the toggle switch at the upper right of the radio was added. It appeared to be wired to simply switch off the speaker. That, combined with the slight rust in a few spots and the numerous scratches that are now apparent on the front of the unit, have caused me to switch plans and repaint the unit. I’ve ordered a reproduction set of lettering for this exact unit, and will sand, prime and repaint the unit in the original color. The hole that was drilled in the case for the non-original toggle switch will be filled with a steel-based epoxy to return the case to it’s original appearance.

There are roughly 50 small electronic components that will need to be replaced, including all electrolytic and paper capacitors. Some wiring will be corrected and replaced with period-correct cloth-insulated solid wire. I’ve noticed tiny hand-written paper tags on many of the wires, presumably from Mr. Zellmer. That adds a bit of charm and is a direct link back to the original owner, so I will retain those tags.

The chassis was quite dusty, so I removed as much dust as I could using compressed air. I’ll clean the chassis with a small brush, which will be tedious work. I’d like to avoid touching the dial cords and pulleys as much as possible.

I’ll begin ordering parts this weekend.

Hallicrafters made radios in Chicago starting in 1932.  Based on the serial number of Uncle Walt’s unit, this specific radio was likely built around August of 1940.  It’s interesting to compare 73 year old electronics with the modern semiconductors in today’s computers.  Fortunately, I have the necessary schematic diagrams and tuning manuals to guide me.  It’s interesting to see the tubes inside the radio, and I’ll likely have to replace a few of those, but the real work will occur under the chassis, where most of the original electronics will need to be replaced.

Look at the World War II-era advertisement of the S-20R below – talk about scaring your customers!  I think the advertisement says “Sure, your church and neighborhood will be bombed, but your Hallicrafters radio will survive.”  This thing is heavy and built like a tank, so that might be true.  I’m sure war time broadcasts were heard on this radio.

I’m still in the research phase, but here’s what I know so far:

1)  The original battleship-gray enamel paint is in good condition and will be left as-is.

2)  The power cord and speaker appear to have been replaced at some point,  I will acquire the proper size and type of speaker and cloth-covered power cord to make it period-correct.

3)  Some tubes will need replacement, but interestingly are still available.

4)  All capacitors will be replaced.  These semiconductors were built around a paste-like material that dries over time.

I will provide updates here as progress is made.  This should be an interesting restoration project.