08-18-2024, 09:20 AM
Good morning, folks! This time I am working on an AC-only model, so it's a bit different than my AC-DC model 49-906. I'm looking at the schematic from the Philco library, and I notice that there is a connection to the chassis ground on the primary side of the power transformer.
The line and neutral connections from the AC cord are connected, via C100A and C100B, to chassis ground. My question is, why would that be? In, addition to stepping voltage up or down, isn't part of the purpose of a transformer to remove any DC reference which exists on the primary side? Granted, I know that the intention of C110A and C100B is to remove any DC offset, but I also realize that real-world capacitors do have some minute leakage.
So far as the power supply section is concerned, I also plan to replace the ripple filtering capacitors (C104A and C104B) with fresh Y safety capacitors. Additionally, I plan to install a 1A fuse socket on the primary side of the transformer. This is a 70W radio, meaning that normal conditions will draw 0.583A at 120V. Thus, I feel that a 1A fuse will be a great safety addition. I also typically replace all capacitors, resistors, and wiring in my restorations. I just feel like it's a good idea to freshen up the insulation on wires and it replaces any brittle or out-of-tolerance components.
The line and neutral connections from the AC cord are connected, via C100A and C100B, to chassis ground. My question is, why would that be? In, addition to stepping voltage up or down, isn't part of the purpose of a transformer to remove any DC reference which exists on the primary side? Granted, I know that the intention of C110A and C100B is to remove any DC offset, but I also realize that real-world capacitors do have some minute leakage.
So far as the power supply section is concerned, I also plan to replace the ripple filtering capacitors (C104A and C104B) with fresh Y safety capacitors. Additionally, I plan to install a 1A fuse socket on the primary side of the transformer. This is a 70W radio, meaning that normal conditions will draw 0.583A at 120V. Thus, I feel that a 1A fuse will be a great safety addition. I also typically replace all capacitors, resistors, and wiring in my restorations. I just feel like it's a good idea to freshen up the insulation on wires and it replaces any brittle or out-of-tolerance components.
Joseph
Philco 46-480
Philco 49-906