01-30-2014, 09:14 AM
I have been working lately on restoring another brand of radio and ran into a problem where the band-switch did not drop positively into position as the knob was rotated. It turned out that the front end of the band-switch assembly has the detent mechanisim right at the front of the band-switch shaft.
I was able to determine that this shaft had two identical flat sides. At one position a flat side was parallel to the bottom edge of the chassis. There were two screws that held the shaft/detent assembly to the chassis. I positioned the switch such that a flat side was in the position parallel to the bottom of the chassis, made a witness mark on that flat side using my scribe and for good measure used a permanent marker to put a dot on that spot. Removing two screws on the flange of the detent part of the shaft assembly allowed me to carefully remove the shaft/detent assembly from the radio. I will leave the switch wafers undisturbed until after I get new ball bearings and reinstall the assembly into the switch wafers. The one remaining ball (one of two) was measured with dial calipers and was 3/16 inch OD or 0.1875 inch OD. I found I could order this size ball from http://www.bocabearings.com for $3.45 plus $2.00 shipping in a quantity of 10 for a single bag of parts. I think this may be a common size for radios made in the 1930-early 1950s radios and perhaps audio amplifier function switches. The company has numerous other sizes available in case you need a smaller or larger ball bearing.
Joe
I was able to determine that this shaft had two identical flat sides. At one position a flat side was parallel to the bottom edge of the chassis. There were two screws that held the shaft/detent assembly to the chassis. I positioned the switch such that a flat side was in the position parallel to the bottom of the chassis, made a witness mark on that flat side using my scribe and for good measure used a permanent marker to put a dot on that spot. Removing two screws on the flange of the detent part of the shaft assembly allowed me to carefully remove the shaft/detent assembly from the radio. I will leave the switch wafers undisturbed until after I get new ball bearings and reinstall the assembly into the switch wafers. The one remaining ball (one of two) was measured with dial calipers and was 3/16 inch OD or 0.1875 inch OD. I found I could order this size ball from http://www.bocabearings.com for $3.45 plus $2.00 shipping in a quantity of 10 for a single bag of parts. I think this may be a common size for radios made in the 1930-early 1950s radios and perhaps audio amplifier function switches. The company has numerous other sizes available in case you need a smaller or larger ball bearing.
Joe
