Restoration Projects

I collect and restore old Motorola AM table top radios

1940-1960

(There is nothing like the audio quality of a all tube radio)

Completed

My Latest restoration project just completed:

Motorola Model A2N

Serial# 8375

Vintage: 1959?

Principle: Super-hetrodyne 455Khz IF

(5) Tubes 12BE6 12BA6 12AV6 50C5 35W4

The audio is no less than perfect

Clean, crisp and sharp

Nancy uses it in the living room to listen to Rush and Sean

Motorola Model 53H

Serial# 33785

Vintage: 1953

Principle: Super-hetrodyne 455Khz IF

(5) Tubes

Motorola Model 5H1

Serial# 103158

Vintage: 1950

Principle: Super-hetrodyne 455Khz IF

(5) Tubes 12BE6 12BA6 12AT6 50C5 35W4

I purchased this Freed-Eisemann FE-15

radio receiver from a fellow ham.

These are extremely rare and and even more rare to find one

in pristine condition as this one is!

Batteries NOT included!

In fact batteries no longer exist for this radio.

I will have to build a power supply for this beast!

This will be my most challenging restoration project.

This is old old technology.

Principle: neutrodyne

The Neutrodyne was a particular type of Tuned Radio Frequency (TRF) radio receiver, in which the instability-causing inter-electrode capacitance of the triode RF tubes is cancelled out or "neutralized". In most designs, a small extra winding on each of the RF amplifiers tuned anode coils was used to generate a small antiphase signal, which could be adjusted by special variable trim capacitors to cancel out the stray signal coupled to the grid via plate-to-grid capacitance.

The Neutrodyne circuit was developed in the early 1920s by Alan Hazeltine.

To properly set up a Neutrodyne receiver, not only did the circuitry need to be aligned for peak performance, (that is, getting all its tuned circuits operating "in step"), it also had to be neutralized.

You almost had to be a radio geek just to get it work.

This technology was better than the superhetrodyne of that day and It wasn't until the 30's until there were some major improvements on Edwin Armstrongs superhetrodyne circuit.

Built in 1925 and sold for $9.95

(That was a lot of jing back in the day)

In todays money that would equate to $112.00

I finally did find a schematic for this jewel!

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