Missy Lisa. . . .




Not being certain of your degree of expertise in techno comprehension, I will just start off with some preliminary info.


Your problem with the Airline set is very probably related to an incremental drying out of the “moist” electrolyte within a canned electrolytic capacitor used in the power supply section of that set over a 50+ year time span.


Instead of the pure DC voltage that it is supposed to be supplying to the tubes in the set, it is instead, replicating, to somewhat of a degree, the AC waveform which you are feeding into the set from the AC line. Thus, the undesired . . . .subtle. . .moderate . . .or overpowering HUMMMMM . . . . which is now emanating from the sets speaker.


I might now ask for you to confirm that the noise is STILL present, even when you have the sets volume control set to its MINIMUM volume position.


Placed below is a marked up thumbnail schema of the sets power supply.


Looking at the far left center one sees the AC line plug with its two flat pin connectors, of which the bottom positioned ones goes to the right and on down to the switching mechanics of converting between battery and AC line operation. THAT line is not the one of interest, instead, it is the FUSCIA marked up one that routes to the right and ends up getting connected to the selenium rectifier of the set, a photo of a selenium is also shown at the bottom, with your sets unit probably having fewer plates and being larger in squared area, their color schemes vary also. Mainly, my referring to the selenium was merely a land mark on the route to the two section power resistor that has its positive output terminal then being initially connected to resistor R13-B . The tap of that resistor finally connects to the first section of your mystery. . . .canned electrolytic capacitor . . .. Its four sections have been YELLOW highlighted as well as my having re-designated their values to 21st century, common, easy to locate values, for replacements, in place of the 4 sections older values that were being given.

That can be done by the using of four SEPARATE individual units in place of the 4 sections contained within the old can.

The cans 4 individual terminal wiring clusters are individually lifted and each connected to its own insulated terminal mount. The individual 4 new capacitors are then wired to those 4 terminals with the capacitors negative leads sharing a common buss.

The picture choice of the of the “altered” can capacitor shown was mainly for the presence of the side lettering logo, that shows that the 4 lugs coming out of the center of the can are marked with symbols of a half moon-square -triangle and the fourth being a blank or no designation at all. They are either being embossed into the bottom phenol disc that the terminals are coming out from, OR sometimes being CUT into the phenol, right NEXT to the terminals. That manner then identifies the capacitor section / value to its associative terminal.


C14- A and D. . . . . . 47 ufd @250 VDC rating

C14-B. . . . . . . . . . .220 ufd @ 16VDC rating

C14-C. . . . . . . . . . . .22 ufd @ 16VDC rating

Since the back opens on your set, I would expect the can being covered with a protective black cardboard insulative cover, in which case, expect that terminal info to be embossed into that cardboard cover.