When you turn the chassis of a Model 19TX upside down, you will receive a surprise – an extra coil mounted underneath!

The coil is physically located close to antenna coil (2), and is mounted in a cylindrical container which looks similar to the set’s second IF transformer. It has three terminals on top. The pictorial below shows the placement of the coil, labeled “Balun” in the drawing.

The parts layout above does not match the 19TX exactly. The drawing is from a Model 89 Code 123, modified to show where the extra coil is mounted. An actual factory under-chassis drawing of a Model 19 Code 126 has yet to be found, which the 19TX (Code 127) is based on.

The partial schematic above shows how the coil mounts in the circuit.

It appears these sets were set up at the factory to be used with the Philco Three Purpose Aerial which was available at the time (mid-late 1933), which used a twisted pair lead-in which connected to a balun transformer which was to be mounted close to the set’s antenna and ground terminals. In the case of the 19TX, it does not have antenna and ground terminals mounted on the chassis – rather, the lead-in wires go through a 25-foot cable to the set’s separate speaker cabinet (see Speaker Hookup, Models 14LZX-19LZX-19TX-91RX for more information on this). Thus, the balun is mounted inside the chassis of the 19TX.