I knew that Sue's radio was unusual  but it is more special than I had thought:

https://www.russoldradios.com/blog/old-radiosradioproject-update-iv

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UPDATE 12-16-2021
We now know the the Aetna model is 252P under Walgreens. It is a 4-tube  + ballast Tuned Radio Freq receiver from 1936. Most of the radios found in this cabinet are 550s, which is a superheterodyne rather than a TRF.  The super is relatively rare. The TRF is much more unusual.

Russ

I know that a lot of people have wondered what would happen if a person was to design a receiver - a TRF receiver, that had one high gain tube driving another and so-on. With this chassis it is easy to find out. Like the front end in a Zenith Stratosphere this chassis has a tuned 6D6 driving another, in this case a 6C6. Well, the answer is that LOTS of RF gain can get you - squealing, motorboating and eventually  - nothing. Even in the Strat, they had to turn off one of the 6D6s on some bands to keep the noise down to a controllable level. Unlike the Strat, or any super, this radio has no IF to narrow and amplify a specific freq so strong stations can be over powering to weak stations.

With this radio it is best to decide what kind of antenna you are going to use and align the radio to that antenna. A longer antenna will provide the noises mentioned above and a shorter one will make weak stations - weak. While the schematic in Riders says not to bend the plates on the tuning cap, linearity across the band is poor. Maybe someone already bent the plates or maybe they need some adjustment, but the spot (freq) you choose to  align to is going to be the sweet spot all else going down hill from there.

​No wonder they replaced this chassis with the 550 super. 

I thought that I took some chassis pics as we updated the radio with re-stuffed caps we found over the last 7 years. I'll try to find them.

For internet searchers:

What the hell is wrong with my -
5-S-119
5-S-126
5-S-127
5-S-151
OR any early 5516 chassis.

​Use this post and the Part 1 below to correct later 5516 chassis parts discrepancy.

Zenith 5-S-151

It seems that Zenith never posted a corrected schematic or parts list. All of these issues come from the early use of a 2125 ohm field coil speaker. Most of these chassis came with a 1000 ohm speaker.

Zenith 5-S-119

Zenith 5-S-126

IMPORTANT NOTE: When servicing one of these chassis it is not mix and match. If your speaker has a 2125 ohm FC use the original schematic . If your chassis has a 1000 ohm speaker use the corrected schematic and parts list.

In all honesty, the original configuration does not work as well as the latter. I suspect that the speaker spec was an error and , rather than eating the cost the wrong part, Zenith used them anyway. From what I have seen radios having the early speaker (2125 ohm) are far less common. I have observed both the 6.5" and the 10" speakers with 2125 ohm FC, but I have not seen an 8" ((49-152) speaker with the 2125 ohm FC.

Original graphics courtesy Nostalgia Air/Ryders

I have been studying these radios for a while along with their battery powered brethren. So I ended up with quite a few "extra" parts. 

I have (had) a 5648 chassis out of a 6-S-330 complete with speaker, all restored. I didn't have a cabinet and never really liked the photo finish offered on the 1938 model. So I put the slightly better 6 toob chassis in a 5-S-127 cabinet and the result is 6-SX-127, the radio they never built but should have.

The cabinet for this one came from PayBay. There is a seller offering a lot of parted-out cabinets and chassis parts. This one looked ok from the sale pictures, but when it got here, well, it was a mess. It had been refinished poorly and sanded hard and dropped at least once. So I decided to reveneer the top and front with book-matched walnut burl, which is a lot more figured than the Zenith stock veneers.

Fuzzy, the ATV riding shop-cat and friend for almost 20 years had just passed so I had no inspiration to move on. The cabinet just kept getting smoother and shinier until it was hard to photograph, especially outside like I normally do.

I miss that old cat.

​Russ