10-12-2024, 02:05 PM
Hi TN Allen,
Prayers for improvement in your health!
+1 on what Chas said. the 5V power supplies for the 80 and 71A must be separate, because the 80 filament is about 180- 230V (for this radio) above ground. The 71A filament is about 30V above ground. the 27 and 26 filaments are 9V above ground. So both voltage and bias, as well as isolation of the rectifier filament, is why the original power supply has separate filament windings for the 80, the 71A, the 27 and the 26s
Yes, the Radiola 18s can be found on "the Bay" often. However, your building a power supply is a great exercise in electronics troubleshooting. I can't find the article, but years ago, someone actually converted a Radiola 18 to a superheterodyne. He built his own PS but I think that he substituted 24As for the 26s, which made the supply easier to build.
The hardest part of your supply is generating the 1.5VAC, as almost nobody builds a transformer for that value.
You state that you have a 5VDC 10A Power supply. Do you have four UX201A (01A) tubes? If so, you can use that power supply for the 1st AF and the 3 RF tubes. However, you cannot use it for the 01As and the 71A together, and absolutely cannot use this power supply for the '80 filament. The 80 filament MUST be isolated from all other filament supplies.
Looking at the schematic for the radio and the power supply, I would not worry too much about smoking your one good power supply. The only thing that I would worry about are the 2 dual capacitors on the radio chassis, the 2 0.5uF caps that bypass the filaments and the 2 0.5uF caps that bypass the B+ supplies. Best to replace them in all the chassis that you intend to use. You could put fuses in the filament lines, about a 6A fast fuse in the 1.5V circuit for the 26's, a 2 A fuse for the '27 and a 1/4A fuse for the '71A
The following are the "Victor" schematics for the RCA Radiola 16.17. 18 in one document, for comparison purposes:
The following is a link to an article on Nostalgia Air on restoration of a Radiola 18:
http://www.nostalgiaair.org/References/A...la18-2.htm
My grandparents had a Radiola 17 which my Grandmother wanted to give to me for many years. I used to play with it in her basement (the radio worked rather well) but Dad did not want to add it to my junk Oops- collection. When I married and Grandma was selling the house, I could not find the radio. Someone took it. I ended up buying one from eBay back in about 2009, when working ones were going for in excess of $100.00. I think I paid about $75 for the radio and shipping. When I got all of the tubes, lo and behold, it worked. Nowadays, you can't even give these things away, so you should be able to win a power supply rather cheap (except for the shipping). Remember to ensure that it is an 18 power supply, not a 17 power supply. However, the transformers are the same.
Prayers for improvement in your health!
+1 on what Chas said. the 5V power supplies for the 80 and 71A must be separate, because the 80 filament is about 180- 230V (for this radio) above ground. The 71A filament is about 30V above ground. the 27 and 26 filaments are 9V above ground. So both voltage and bias, as well as isolation of the rectifier filament, is why the original power supply has separate filament windings for the 80, the 71A, the 27 and the 26s
Yes, the Radiola 18s can be found on "the Bay" often. However, your building a power supply is a great exercise in electronics troubleshooting. I can't find the article, but years ago, someone actually converted a Radiola 18 to a superheterodyne. He built his own PS but I think that he substituted 24As for the 26s, which made the supply easier to build.
The hardest part of your supply is generating the 1.5VAC, as almost nobody builds a transformer for that value.
You state that you have a 5VDC 10A Power supply. Do you have four UX201A (01A) tubes? If so, you can use that power supply for the 1st AF and the 3 RF tubes. However, you cannot use it for the 01As and the 71A together, and absolutely cannot use this power supply for the '80 filament. The 80 filament MUST be isolated from all other filament supplies.
Looking at the schematic for the radio and the power supply, I would not worry too much about smoking your one good power supply. The only thing that I would worry about are the 2 dual capacitors on the radio chassis, the 2 0.5uF caps that bypass the filaments and the 2 0.5uF caps that bypass the B+ supplies. Best to replace them in all the chassis that you intend to use. You could put fuses in the filament lines, about a 6A fast fuse in the 1.5V circuit for the 26's, a 2 A fuse for the '27 and a 1/4A fuse for the '71A
The following are the "Victor" schematics for the RCA Radiola 16.17. 18 in one document, for comparison purposes:
The following is a link to an article on Nostalgia Air on restoration of a Radiola 18:
http://www.nostalgiaair.org/References/A...la18-2.htm
My grandparents had a Radiola 17 which my Grandmother wanted to give to me for many years. I used to play with it in her basement (the radio worked rather well) but Dad did not want to add it to my junk Oops- collection. When I married and Grandma was selling the house, I could not find the radio. Someone took it. I ended up buying one from eBay back in about 2009, when working ones were going for in excess of $100.00. I think I paid about $75 for the radio and shipping. When I got all of the tubes, lo and behold, it worked. Nowadays, you can't even give these things away, so you should be able to win a power supply rather cheap (except for the shipping). Remember to ensure that it is an 18 power supply, not a 17 power supply. However, the transformers are the same.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
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