RCA Little Master A

RCA Little Master A

Manufacturer: RCA Victor Canada
Model: Little Master A
Approximate Date Of Manufacture: 1948
Type: 5-tube Superheterodyne AC/DC AM broadcast band radio
Tube lineup: 35Z5GT, 50L6GT, 12SK7, 12SA7, 12SQ7
Status: working, restored
Where purchased: eBay, April 2004

Description

This is a pretty standard five tube AM radio with a brown bakelite case. It has a phono input on the back which is always active. One knob appears to have broken in shipping but all pieces were there. There was no line cord, the chassis was loose in the case, and it was a little rusty (the chassis, and some of the metal tubes). Despite the good shape on the outside, the insides had a number of problems.

I was able to obtain a schematic from JustRadios. I later also found a copy in my CD-ROM of RCC manuals.

Restoration started with a good cleaning. I fixed the cracked knob and repaired a small crack in the case with cyanoacrylate glue. While removing the tubes I inadvertently cracked the 50L6GT tube, requiring that I buy a replacement. I replaced the line cord and pilot lamp.

After slowly powering it up with a variac and isolation transformer, the radio came up and picked up a station. A good sign, and somewhat surprising.

At least one cap and the filter cap had been replaced at some point. All wax caps were replaced, as well as the electrolytic filter caps. I measured the values of all caps and resistors, and replaced one resistor that was open. Some of the wires to the internal loop antenna had come loose and were resoldered.

There seems to be a few small differences between the schematic and the circuit. I'm not sure if the radio was modified or the design changed.

The volume control is still a little noisy and may need to be replaced. In fact, even the power switch on the control seemed to be open until I used some contact cleaner on it.

Pictures