Ok, now is time to post my first question. I have a Philco 46-1213 that I am going to start working on here real shortly. I have been studying the Schematic for the last few days. I am completely new at reading them, but I have been doing a lot of research and have watched several videos. They're starting to make more sense to me, but I have a long way to go. My first task for this radio is to replace the crumbling 2 prong non-polarized plug. I want to use a 3-wire cord, with an inline fuse. My trouble with reading the Schematic is I don't understand which connection is the neutral wire. I will attach a photo of my schematic. How do you decide which leg is neutral so not to place the power on the chassis?
Larry
Elsberry, MO
Philco 46-1213
Zenith 12S568E
(This post was last modified: 8 hours ago by MissouriLarry.)
Hello Larry. Replacement of the power cord is a priority, but not the first. All paper and electrolytic capacitors need replacement before introducing electricity to the mix. All resistors should also be tested, and all out-of-tolerance replaced. The Bakelite block in your picture has two filter caps that require safely caps when you rebuild it. Several tutorials are available here for rebuilding tips. There is no reason to install a three-pronged plug. Those safety caps provide your path to ground. Hope this helps. Take care, - Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
Usually you'll want to attach the hot side of the power line cord to the power switch. That way when the switch is off there is no source of voltage other than the power switch. Looking at your schematic you have a situation where the line filter caps (75A and 75B) always have power on them when the power cord is plugged in. I always rewire them to the other side of the power switch so they only have power when the switch is on. BTW these caps should be replaced with Y2 safety caps.
Gary,
Thanks for the reply! I have no intention of introducing any electric to my radio until I recap it. I just wanted to pick a place to start, and I figured the cord was a good starting place. My thoughts of a 3 wire were to have a ground on the chassis, but if that is not needed then I would still like to use a polarized 2-prong. Still, I am confused how to choose which side of the terminal is the neutral and which is the load. How does one distinguish from the schematic which is which? I've read that the neutral often is on the switch side of these, but I am not sure. I would like to learn how to decipher this from the schematic for future knowledge if anyone can help.
In the photo of my Chassis, I now have two wires marked "A" and "B", these are my power cord wires. What I am trying to find out is which of these wires should be the neutral wire and which should be the power wire? Looking at the schematic I cannot figure out which is which, and if you do know I would like to know how to figure this by the schematics.
You have to examine the connections to A and B to see which one matches the schematic. It appears there are two white wires on A. If one goes to the transformer and the other goes to the phono power plug then A is the neutral.