Carefully I opened this nice shipping box. And out came... a beautifully
preserved RCA Victor 87T-1 radio, dating from 1938!
The cabinet was in such a good shape indeed that I could well leave it untouched. I just cleaned away the most obvious dirt, but left some in place: a radio with original finish but without any dirt looks suspicious! The only "outside" thing I had to do was making two knobs. Only the concentric knobs at the center were there, while the two side knobs were missing. But in a collector's handbook I found a photo of a 86T-1 radio, which is the same thing without the magic eye, and that photo clearly showed that the radio's side knobs were identical to the center part of the concentric knob! Eureka! I made two replicas of that center knob by the method outlined in the article about the Belmont 542 radio, and the original look was restored!
Inside, things didn't look so bright. Roberto had told me that the radio
was actually playing when he got it. It was just making terrible noises
when I got it. There were a lot of intermittent contacts, causing
problems. But the actual situation was even worse: The radio had been extensively
modified! Only two tubes were of the original types. So, the first thing
to do was getting a schematic diagram, which fortunately was easy (these
RCA radios were very similar among them!), and getting the missing tubes.
After some considerable effort in restoring the technical side, this is how the chassis now looks. Note that the radio uses a complete lineup of metallic octal tubes, except for the magic eye of course! It was a very modern radio in its time! It was built in 1938, and metal tubes were quite new then. It's interesting to note that the radio uses several top-cap tubes, as single ended RF signal tubes were still unavailable.
Here is the tube lineup: A 6A8 converter, 6K7 IF amplifier, 6H6 detector and AGC, 6F5 audio preamp, 6F6 audio power amp, 6U5 magic eye, 5W4 rectifier.
The most important modification I had to undo was that the 6H6 and the 6F5 had been replaced by a single glass 6SQ7GT. It worked very well, but just was not original! So I returned to the 6H6/6F5 circuit.
All original electrolytic capacitors in this radio were bad, but still
in place, disconnected, and others had been fitted. I replaced one of the
replacements, which was also quite dry already. In addition I had to replace
a few leaky paper caps. Now the radio works quite well, but sometimes breaks
into self-oscillation. I still have to find out where the loose connection
is. It reliably returns to normal operation after spanking it! Pavlov's
method can be applied to old radios! :-)
Here is a close-up of the restored 6H6/6F5 section. My 6F5 is an GE tube rather than an original RCA "Radiotron". Sorry! And the top connection is from a junked Philips radio, but it could pass as original for unknowing people... The dual electrolytic capacitor behind is disconnected, and modern ones under the chassis do its job.
This set was made for sale in spanish-speaking countries. The label reads in Spanish: "By connecting here an RCA phono adapter, you will convert this receiver into a magnificent radio-phonograph." Nice, huh?
Here is the inside of the repaired radio. Did you notice that this chassis is very narrow and high, with the tuning capacitor centered over the chassis? The reason is simple: 1938 marked the time when vertical radios, like the cathedrals and tombstones, definitely fell out of favor. But RCA had a lot of good chassis designs for such kinds of enclosures! So they kept using those designs, those parts, those chassis', and simply built them into "modern" horizontal cabinets. If a lot of space got lost, so what? If the dial and the knobs were on one side, and the speaker on the other, destroying symmetry, so what? The buyers wanted horizontal radios, RCA had a stock of chassis' for vertical radios, so they put their chassis' into horizontal boxes and sold them. Everyone was happy. Note that the speaker cable is much longer than needed for this cabinet. It's the length required to mount the chassis and speaker in a vertical tombstone cabinet, as specified for the original design!
There is just one thing I will never like about this radio: Metal tubes don't glow in the dark. And the black paint smells when hot!