Sobell ST301 MW & LW radio 1960

In all my years of looking I've never seen another one of these, just a taj different with the recessed control panel and geared down LW & MW tuning dial, nice gold plated speaker grill and runs on a PP6 or PP9 at a push (9v). Built in 1960 with a rexine covered wooden cabinet. It was badly covered in nicotine at the rear and had a few dents in the speaker grille.

Sobell was a company set up by the Jewish Sir Michael Sobell (1892-1993) who joined with GEC in 1961. This model is quite scarce and shares it's chassis with the McMichael MT 102 a company he merged with in the mid 50's. The sound quality is very good and it AGC circuit gives sensitive coverage  of both bands, it also had a car aerial socket on the side, as car radios were quite scarce in the late 1950's, and mostly bulky valve models.

The repair

As usual I stripped everything down, as the speaker grille needed removing to straiten out the dents. Two brass screws at the rear and underneath release the wooden cabinet from the front. You'll also need to un-solder the aerial socket to separate the cabinet for cleaning.  A kichen bleach cleaning spay washed away the yellow and gave it back it white finish, take care with coloured Rexine as ammonia (in bleach) does sometimes remove printed colours and text from dials. As usual I apply with an old toothbrush to get into the textured grooves that tend to hold dirt for decades. 

The cleaning transformation is just amazing, to think it hasn't been cleaned in 60 years?
The speaker grille is held in by a 6 x bend-over clips and two more rubber clips either side at the top of the grille. The company logo also holds the metal grille in place and is removed by melting it's plastic clips inside, hiding inside the loud speaker area. I removed the dents with a ball end of a screwdriver handle using a scanning motion on the inside, careful not to over push. Then cleaned with 70% alcohol mixture to remove grease.

Still using massive audio transformers is a harp back to the valve days, with the introduction of transistor radios they would soon be designing them for 10 mA current usage (10 x smaller) than 100's that was used for valves. The same can be said for the speaker and the tuning capacitor, in fact miniaturization went mad around this point. I expect is might have been an off shoot from the space race that had started in the mid-50s.

During the process of changing the battery terminals the radio came back to life, possibly open circuit plastic cleave to the battery clip, who knows, but then the cleaning oil was needed to the crackly tuning capacitor, band switch and volume control, take care to use a spay pipe and don't over wash it.
I've included the service data to help others that might need to attempt to repair this lovely model.

I've included service information for the needy

quick snap to remind me where the wires went

As a finishing touch today I added an LED light under the tuning dial to illuminate the clear plastic dial. All that was needed was a 1.5 k ohm resistor in series with the positive wire to LED, and wired to the cold side of the on/off switch. LED's draw very little current so can be on all the while the radio runs with no real extra drain like vintage bulbs once did.

A 1/4 watt rated resistor is sufficient and the long wire on the LED is always the positive side of the diode. Ohm's law calculated 1.7 volts across the diode at 0.05 mA current.