Hi Patrick.
I have restored a similar radio, the 42PT94 and 48-205. There are several restoration techniques:
The simplest is to just lift one end of the wire and slip heat shrink over the defective wire, shrink and reconnect and resolder. Not the prettiest but it works.
If rewiring, any wire 24 gauge through 18 gauge meeting UL1007 (300V, 105 Deg C) or UL1015 (600V, 105 Deg C) will work fine for AA5 AC- DC Sets like yours. If the set has a power transformer, use a heavier gauge for the filaments and use 600V UL1015 for the higher B+ and Rectifier filament wiring. Use stranded for lines to antenna loop and to speaker if they are separate from the chassis. Within the chassis, use stranded or solid, your choice. Solid is easier to hook up to socket terminals, etc.
Please note that not all "hookup wire" or "primary wire" available at hardware or auto parts stores will meet this spec. I like Remington Industries as a supplier. They make a nice kit of wire in about 6 or 10. different colors in a cardboard "dispenser". Their website is
https://www.remingtonindustries.com/hook...ectronics/
Some of the "experts" on the Phorum may have sources of exact replacement rubber wire. This is only needed if you are attempting to make an exact restoration (stuffing capacitors, exact wire match, etc.). This is usually reserved for the rarest and most desirable high end sets such as Zenith Stratospheres, Scott, etc. As to color, you can match the original. Over the years, different manufacturers used different color schemes. I use the following which approximates what most radios of the 1950s use for AA5 AC - DC sets like yours:
Red- B+ (higher value, from rectifier
Orange- B+ (lower value after a resistor)
Blue- Plate
Green- Grid
White- AVC
Black- Common B- and 1st AF end of filament string
Brown or Grey - Filament or Heater
Please note that your Philco may not have followed the above scheme.
Note that the order of tubes in the filament (heater) string is to a particular design to minimize hum and to meet specs for maximum voltage difference between heater and cathode. Generally, the Rectifier filament is at the "high" or "hot" end of the string, followed by the AF Output tube. the detector / 1st AF tube is always at the low (ground) end of the string.
Try to keep the wire routing exactly as the original.
One other word of warning:
These sets are referred to as "hot chassis", as the common B- (ground) is grounded to the chassis through a capacitor and resistor. The switch is in the line connecting to common B- and 7C6 end of the filament string. refer to the schematic for a clearer picture. If the power cord is plugged in to house power so that the switch is connected to the "hot conductor" of the house power, then one can receive a shock with the switch on but no shock with the switch off. If the power cord is plugged in so that the switch is connected to the "neutral" conductor, then the opposite happens, that with the switch on, the chassis is at ground potential, but with the switch off, the chassis becomes hot through the tube filaments that are low resistance. therefore, when rewiring, most restorers change the wiring to put the switch on the "Hot (rectifier input and 35Z3 end of the filament string)" end of the circuit and use a polarized power cord. When installing a polarized power cord or plug, the wider plug prong connects to the "Neutral" leg of power and to the "common B- and 7C6 end of the filament string" of the radio. The Hot (rectifier input) end connects to the power switch, then through the switch to the rectifier input and 35Z3 end of the filament string.
An expert on the forum may have an article on this.
Hope that all of this helps.
Best regards,
John, MrFixr55
