The PHILCO Phorum
Recommendations for wires - Printable Version

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Recommendations for wires - patrickdickey52761 - 01-14-2023

Hi, everyone,

I have a few radios that I need to start restoring. One is a Philco 42-322 and another is a Philco 42-321. On the 42-322, the wires are all cracked up and the insulation is falling off in places. So, my question is what wire would you recommend to replace all of them? And, if you've restored one of these radios, what colors did you use? If I can, I want to keep the color scheme as close as possible.

Thanks in advance, and have a great day. Icon_smile
Patrick.

RE: Recommendations for wires - morzh - 01-14-2023

Gage-wise, anything from 24 to 18 is good.
Coth-covered is sold by Radio Daze and other places.

RE: Recommendations for wires - klondike98 - 01-15-2023

There is an article in our library about the rubber coated wires and their replacement in our library.
https://philcoradio.com/library/index.php/shop-talk/techniques/rubber-covered-wiring-1939-1942-philcos/

RE: Recommendations for wires - promocom - 01-15-2023

I just got some from Antique Radio Supply in 22ga sizes I might get the 20ga next time but not 24ga at least for topside.  It is very close to original look too.

RE: Recommendations for wires - patrickdickey52761 - 01-15-2023

I'm thinking that I might go the heat shrink route this time through. Especially since it sounds like the wiring has to be precise, and this is my first time restoring a radio. Plus, it minimizes the number of things that I have to desolder and resolder.

Quick question on this. Would it be smarter to heat shrink each wire as I go, or get all of the heat shrink on and just run the hot air gun over the entire chassis at one time? I can see the advantages and disadvantages of both techniques. Or, am I overthinking this?

Have a great day. Icon_smile
Patrick.

RE: Recommendations for wires - MrFixr55 - 01-15-2023

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-up-wire/electronics/

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

RE: Recommendations for wires - RodB - 01-15-2023

Hello Patrick,

I've done the heat shrink and lifting one end cuts the time to do it by almost half. What you want to do is identify all the wires you want to cover for each color then mark the schematic so you can check off each one as you go. The major lines are B+, B- and AVC. I usually go with red, black and yellow respectively. Then use white or blue for others. Once you identify the three major ones you'll find it much easier to find test points later on. The busy spots you will have to go with the flow and get to a color you're not working on. GL with the project.

RE: Recommendations for wires - GarySP - 01-15-2023

I've gotten cloth covered 20 gauge wire from vendors at swap meets in just white braided cloth insulation. To color code the wire I use an appropriately colored Sharpie dry marker and draw a "trace color line" on the outside of the wire end to end. As John stated above, I prefer solid core wire to stranded as it will take routing easier with its' rigidity, and proves a lot easier to fit into solder lugs, especially when numerous wires are connected in the same solder point. I use stranded wire only in situations where the wire needs to 'move' with the operation. Take care and BE HEALTHY! Gary