02-09-2022, 06:09 AM
Hi Cdoyl, If "not yet", you will get there!
I am way too wordy, but please read through the entire post and take the advice of any "Expert" that posts.
The instructions below are given assuming that you have a schematic diagram and can recognize the parts described. These instructions are also based on you having either "recapped" the radio or that the radio successfully functioned. If you have obtained this radio in original, unrepaired condition, then do not power up this radio until all electrolytic caps have been replaced. In fact, all capacitors, including all of the "wax paper" caps should be replaced. Failure to do so can cause failure of other parts, especially transformers and may cause a fire!
There are many good threads and articles on recapping, especially on this "Phorum" If you have no experience in electronics or vacuum tube circuitry, please read through these posts. Do not be discouraged, but do be safe. There are voltages present in this set when the underside of the chassis is exposed that can kill you.
The Schematic is available at Nostalgia Air, a wonderful service that provides "Rider's" Schematics at no charge. Google it. The Website is fairly intuitive. Hopefully, this link will work:
http://www.nostalgiaair.org/PagesByModel...013521.pdf
Look at your old speaker. The 2 solder lugs directly on the frame of the speaker are the "voice coil" connections. The new speaker will have the same thing. Connect the wires from the "secondary" of the Audio Output Transformer" to these solder lugs. Polarity is not important because this is not stereo. There are 2 wires from the frame that go to a "winding" on the Field coil (generates the magnetic field, your new speaker will not have this). Ignore these. These are connections to the "hum bucking coil". As to the 2 long wires on your old speaker, these are for the Field Coil, and don't exist on your new speaker, but must be dealt with. The simplest thing to do, if there is room in the radio (and I bet that there is not) would be to mount the old speaker, or at least the field assembly (after you cut it away from the frame of the old speaker) somewhere inside the radio. For example, if the cabinet is big, mount the entire speaker frame either behind the replacement speaker or ion the underside of the radio. If there is no room for the frame, mount the field coil somewhere on the chassis, near the power supply area and away from the tuner. Consideration must be given to electrical and heat safety issues. If there is no room for the field coil, it can be replaced with a 1600 (1.6K) Ohm 5 watt (or better yet, 10 Watt) resistor. Again, consideration must be given to locating this resistor as to electrical safety and heat. If you can obtain an aluminum encased chassis mount version of this resistor, this will be good. If you replace the field coil with a resistor, change the two power supply electrolytic caps, labeled 57 and 49A to a higher value start with 20uF for both caps. If there is too much hum, increase to 33 uF for cap 40A. Do not exceed 33 uF for the cap labeled 57 between the 7Y4 cathode and center tap of transformer secondary. the cap labeled 40 (likely in the same "can" as 40 A should remain at 4uF or 5uL. Don't go much higher or this will put too much load on R42.
Keep asking questions if you need help. Good Luck!
Best Regards,
John, MrFixr55
I am way too wordy, but please read through the entire post and take the advice of any "Expert" that posts.
The instructions below are given assuming that you have a schematic diagram and can recognize the parts described. These instructions are also based on you having either "recapped" the radio or that the radio successfully functioned. If you have obtained this radio in original, unrepaired condition, then do not power up this radio until all electrolytic caps have been replaced. In fact, all capacitors, including all of the "wax paper" caps should be replaced. Failure to do so can cause failure of other parts, especially transformers and may cause a fire!
There are many good threads and articles on recapping, especially on this "Phorum" If you have no experience in electronics or vacuum tube circuitry, please read through these posts. Do not be discouraged, but do be safe. There are voltages present in this set when the underside of the chassis is exposed that can kill you.
The Schematic is available at Nostalgia Air, a wonderful service that provides "Rider's" Schematics at no charge. Google it. The Website is fairly intuitive. Hopefully, this link will work:
http://www.nostalgiaair.org/PagesByModel...013521.pdf
Look at your old speaker. The 2 solder lugs directly on the frame of the speaker are the "voice coil" connections. The new speaker will have the same thing. Connect the wires from the "secondary" of the Audio Output Transformer" to these solder lugs. Polarity is not important because this is not stereo. There are 2 wires from the frame that go to a "winding" on the Field coil (generates the magnetic field, your new speaker will not have this). Ignore these. These are connections to the "hum bucking coil". As to the 2 long wires on your old speaker, these are for the Field Coil, and don't exist on your new speaker, but must be dealt with. The simplest thing to do, if there is room in the radio (and I bet that there is not) would be to mount the old speaker, or at least the field assembly (after you cut it away from the frame of the old speaker) somewhere inside the radio. For example, if the cabinet is big, mount the entire speaker frame either behind the replacement speaker or ion the underside of the radio. If there is no room for the frame, mount the field coil somewhere on the chassis, near the power supply area and away from the tuner. Consideration must be given to electrical and heat safety issues. If there is no room for the field coil, it can be replaced with a 1600 (1.6K) Ohm 5 watt (or better yet, 10 Watt) resistor. Again, consideration must be given to locating this resistor as to electrical safety and heat. If you can obtain an aluminum encased chassis mount version of this resistor, this will be good. If you replace the field coil with a resistor, change the two power supply electrolytic caps, labeled 57 and 49A to a higher value start with 20uF for both caps. If there is too much hum, increase to 33 uF for cap 40A. Do not exceed 33 uF for the cap labeled 57 between the 7Y4 cathode and center tap of transformer secondary. the cap labeled 40 (likely in the same "can" as 40 A should remain at 4uF or 5uL. Don't go much higher or this will put too much load on R42.
Keep asking questions if you need help. Good Luck!
Best Regards,
John, MrFixr55
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
