Telechron Musalarm 8H59

[PJL]

Rumoured to be one of the first clock radios, this USA set was launched in late 1945. It is a broadcast only TRF model and is made by GE although marketed under the name of their electric clock division.

It has a tiny chassis designed for 4 octal valves but this is a slightly later model with a 35W4 fitted. When I first saw it I thought it was rusty but part of the construction is copper. It uses permeability tuning to keep the size down and has a 12SG7 RF amplifier with a tuned aerial and anode coil.

I restuffed the wax capacitors, the resistors were within my 25% acceptable tolerance and the electrolytic reformed OK. The only fault was what I assume is a fusible resistor which had done what it was designed to and was o/c.

There was an explanation for this as I discovered when I started checking the valves. The 35W4 and 12SQ7 heaters were o/c and the 12SG7 had a heater/cathode short. The evidence all pointed to a burst of 240VAC and I quickly checked the clock but it had survived. This put the project on hold for a while as I only had a 12SG7 in stock but did give me the time to complete an overhaul of the clock mechanism.

With new valves in place, it did receive some stations but was erratic and whistled. This was fairly quickly tracked down to my wiring and when the AGC capacitor was put in it's corrrect place, and after a realignment following the manufacturers instructions, I have a fairly sensitive but not overly selective radio.

This is the first USA radio I have tackled as they usually fetch a bit more than I like to pay but it has proved to be a pleasent change. My next challenge is to construct a 50 to 60Hz converter for the synchronous clock for which I have drawn a design but need to gather some parts...but then again there are those other projects on the go.

[camtechman]

Great Job!

I have a 'thing' for clock/radios.