Rogers RM503

Rogers RM503

Manufacturer: Rogers-Majestic, Toronto, Canada
Model: RM503
Approximate Date Of Manufacture: 1940s
Type: 4-tube Superheterodyne Battery-operated AM/SW band radio
Tube lineup: 1AC6, 1T4, 1S5, 3V4
Status: working, restored
Where purchased: eBay, April 2004

Description

This is a tube radio which operates from a 1.5V 'A' battery and two 45V 'B' batteries. It receives AM broadcast and shortwave from 1.76 - 5.8MHz and 5.8 - 18.2 MHz. The seller said it was working but there was some damage in shipping. The case was broken, the speaker came loose, and it broke a tube.

I was able to obtain a schematic. It was also known as a Philips PH102 (Philips bought out Rogers-Majestic in the late 1940s). An unusual feature is a tone control switch that works by feeding back audio from the speaker back to the AF amplifier. According to the service manual, the radio only puts out a maximum of 150 milliwatts of audio!

I glued the case back together and cleaned up the case and chassis. The broken 1T4 tube was replaced. Broken speaker wires were resoldered. Three paper caps were replaced - they were not wax covered, but some kind of plastic that was also covered in a sticky substance. All caps and resistors were measured and all seemed to be within spec.

I powered the filaments with a low voltage power supply and rigged up a temporary 90V power supply using a variac, diode bridge, and RC filter. The radio came up and sounded fine. It does need an external antenna and preferably a ground as it does not have any internal antenna.

Later (Aug 2004) I purchased and built a proper A/B/C power supply from Antique Radio Supply and confirmed that it works well. It definitely needs a ground connection and some minimal antenna, if only a short piece of wire.

Pictures

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