04-19-2019, 04:27 PM
Hi again to everyone on the Phorum. I'm new to the Phorum. I've repaired power supplies for tube amplifiers for Amateur Radio use and for a transmitter and a receiver but it will be a new endeavor to work on this Philco. I am starting on my Grandparents Philco Model 41-285 code 121 radio. I'll try and get some pictures posted soon as soon as I figure out the best way to do so.
Anyone familiar with this model knows the rubber wiring needs to be replaced, although there is a lot of wiring that appears okay and is cloth covered. I was not expecting to see the cloth covered wiring which I believe to be original wiring. I do plan on replacing or sleeving all the rubber coated wiring to avoid any future problems with cracking or crumbling. This will also involve the wiring in the band switch, which appears to only have rubber coated and crumbling wiring.
I am not looking to restore this to exactly how the chassis looked when new, but want to restore it to working condition. I have not heard this radio since the mid 1950's.
I say this is a dream/nightmare radio because there have been repairs done in the 1940's-1950's and a relative had someone "tinker" with it to surprise me with a working radio. I am unsure of what the tinkerer actually did and since the capacitors weren't replaced, I do not intend to plug it into line voltage. An inline fuse has been added to the chassis, but there is no polarized cord, so I believe if it were plugged in, even with a blown fuse, the chassis could be hot.
I can see the on-off push button switch has been completely disconnected and there is no continuity with the switch when the on/off pushbutton is pressed. There has been an on-off volume potentiometer wired to turn on the radio and also adjust the volume.
It looks like the power transformer was replaced. There are three wires from the transformer secondary that are not connected to anything and the ends of these wires have electrician's tape wrapped around their free ends. I am going to trace each wire in the chassis as I go to insure they are soldered to the correct places according to the schematic.
The power transformer is a Thordarson T13R12 ID4. I looked this up and it is a 350-0-350@70mA, output is 5V@2A, and 6.3V@2.5A. I know, from reading the Phorum, the original was 525V CT@65mA and 6.4V@3.0A. Will I need to replace the Thordarson transformer? I am guessing the power transformer is good, but I will check it to make sure. I will also need to check the secondary wiring to make sure the transformer was wired correctly. I'll also need to check the audio output transformer. I'm not sure what resistance reading I'm looking for to check the Thordarson primary and secondary wiring.
Looking at the underside of the chassis, I see several solder joints which look dull and may be cold solder joints. I will make sure to re-heat all the solder joints to make sure there are no cold joints while replacing some of the wires.
I have started to work on the top of the chassis to clean it and have removed the ganged tuning capacitors. I did note a wire on the top of the tuning capacitor which had broken and will need replaced. This wire went from the left side of the capacitor and was looped back through an opening on the bracket on the right side of the capacitor to the capacitor bracket in the center top of the variable capacitor. It looks like it was soldered to the top center bracket where it it broke free.
I have one light bulb socket which has a small split at the base and I was unable to remove the bulb. I finally got the bulb free of the socket by destroying the bulb. This is the socket and bulb that lights the push buttons. I will have to repair this socket because the rubber sleeve which acts as a spring is very hard and is no longer resilient and is immovable. I saw a reference to rebuilding a socket on the old Phorum, but the link wasn't any good.
I know I'll have a candohm resistor that will probably need to be replaced.
I've also discovered a pin socket for one of the type 41 output tubes is no longer attached to the fiberboard (?) socket and I will need to repair the socket or install a new one. I know the 41 tube will not fit into the socket and make contact with pin 6. Pin 1 and pin 6 are the heater sockets for the tube.
I have been reading the Phorum on anything to do with this model and am already learning a lot but have a steep learning curve ahead. I want to thank everyone for all the great information on this Phorum.
I know I will have questions as I tackle restoring this radio to operating condition. I'm tackling the chassis first before even thinking about the cabinet which has endured eight moves by indifferent movers, over the past 60 plus years. Wow, do I have a big project to do, since this will be my first broadcast radio restoration. Looking forward to this learning experience.
Roger
Anyone familiar with this model knows the rubber wiring needs to be replaced, although there is a lot of wiring that appears okay and is cloth covered. I was not expecting to see the cloth covered wiring which I believe to be original wiring. I do plan on replacing or sleeving all the rubber coated wiring to avoid any future problems with cracking or crumbling. This will also involve the wiring in the band switch, which appears to only have rubber coated and crumbling wiring.
I am not looking to restore this to exactly how the chassis looked when new, but want to restore it to working condition. I have not heard this radio since the mid 1950's.
I say this is a dream/nightmare radio because there have been repairs done in the 1940's-1950's and a relative had someone "tinker" with it to surprise me with a working radio. I am unsure of what the tinkerer actually did and since the capacitors weren't replaced, I do not intend to plug it into line voltage. An inline fuse has been added to the chassis, but there is no polarized cord, so I believe if it were plugged in, even with a blown fuse, the chassis could be hot.
I can see the on-off push button switch has been completely disconnected and there is no continuity with the switch when the on/off pushbutton is pressed. There has been an on-off volume potentiometer wired to turn on the radio and also adjust the volume.
It looks like the power transformer was replaced. There are three wires from the transformer secondary that are not connected to anything and the ends of these wires have electrician's tape wrapped around their free ends. I am going to trace each wire in the chassis as I go to insure they are soldered to the correct places according to the schematic.
The power transformer is a Thordarson T13R12 ID4. I looked this up and it is a 350-0-350@70mA, output is 5V@2A, and 6.3V@2.5A. I know, from reading the Phorum, the original was 525V CT@65mA and 6.4V@3.0A. Will I need to replace the Thordarson transformer? I am guessing the power transformer is good, but I will check it to make sure. I will also need to check the secondary wiring to make sure the transformer was wired correctly. I'll also need to check the audio output transformer. I'm not sure what resistance reading I'm looking for to check the Thordarson primary and secondary wiring.
Looking at the underside of the chassis, I see several solder joints which look dull and may be cold solder joints. I will make sure to re-heat all the solder joints to make sure there are no cold joints while replacing some of the wires.
I have started to work on the top of the chassis to clean it and have removed the ganged tuning capacitors. I did note a wire on the top of the tuning capacitor which had broken and will need replaced. This wire went from the left side of the capacitor and was looped back through an opening on the bracket on the right side of the capacitor to the capacitor bracket in the center top of the variable capacitor. It looks like it was soldered to the top center bracket where it it broke free.
I have one light bulb socket which has a small split at the base and I was unable to remove the bulb. I finally got the bulb free of the socket by destroying the bulb. This is the socket and bulb that lights the push buttons. I will have to repair this socket because the rubber sleeve which acts as a spring is very hard and is no longer resilient and is immovable. I saw a reference to rebuilding a socket on the old Phorum, but the link wasn't any good.
I know I'll have a candohm resistor that will probably need to be replaced.
I've also discovered a pin socket for one of the type 41 output tubes is no longer attached to the fiberboard (?) socket and I will need to repair the socket or install a new one. I know the 41 tube will not fit into the socket and make contact with pin 6. Pin 1 and pin 6 are the heater sockets for the tube.
I have been reading the Phorum on anything to do with this model and am already learning a lot but have a steep learning curve ahead. I want to thank everyone for all the great information on this Phorum.
I know I will have questions as I tackle restoring this radio to operating condition. I'm tackling the chassis first before even thinking about the cabinet which has endured eight moves by indifferent movers, over the past 60 plus years. Wow, do I have a big project to do, since this will be my first broadcast radio restoration. Looking forward to this learning experience.
Roger
