wire color?
 

I ran out of wire, of all things, the other day when I was working on the Westinghouse. And instead of my usual of buying a single big roll of about 18ga. copper stranded, so I can just use it for everything from my TV to my car, I went and got different color solid wire to match the different colors in the set. Now I know that red and orange always appear to be from different parts of the power supply in the sets I've worked on. But I was wondering if there is consistency between different sets and the other wire colors, blue, white, brown, yellow, etc. I know I could figure this out if I took a couple sets apart at once and compared them, but I'm being lazy. I also thought I might not be the only one wondering about this.

I think that the colors were used to help out techs in tracking problems. i had a number of antique radios that had schematics with labels on the wires that denoted color as a specific purpose.

TVs could be similar, but I'm not certain.

There's a color code for wire indicating its general use. Black is usually a ground or power supply return, red for B+, blue for plates of audio amp tubes, green for control grids, brown for heaters, yellow for cathodes, I think orange is for screen grids. White for AVC circuits? Beyond that, it's pretty much random, depending on what they had on hand that day at the factory.

Power transformers have their own codes. Black is usually the primary, green the 5U4 filament, red the high voltage for B+, brown for heaters, striped wires usually centertaps.

What wa2ise said, except that in any decent manufacturer, it is NOT what was on hand that day in the factory, but maybe what was next in the list of available colors when the set was engineered. The factory would have a prototype in a lucite box that showed everything the way it should be, wire colors and dressing of cables, etc., and deviations would only be allowed if agreed by written order. In cases where some detail really didn't matter, there would still have to be a wirtten agreement to make the change. This might seem picky, but it eliminates liability and reliability issues like substituting the wrong grade of insulation, etc.

This thread would make a good sticky! :yes:

I agree!

From what I see, the video output after the amp to the CRT is usually green or sometimes yellow. In component video, green carried the luma and sync signals.

Jonathan

In Australia yellow was always used for the cathode on CRT's on monochrome sets upto the introduction colour TV in the mid 70's then the cathodes became colour coded, Red for R-Y O/P, Green for G-Y O/P & Blue for B-Y O/P & sometime s White was for the luminace O/P on sets that used CDA drive for the CRT where lumanace was applied to the cathodes & the colour difference was applied to the first grids as was used on early US designs.

This list of EIA color codes was culled from the back of the manual to my Triplett 630NA multimeter...some of this goes way back (i.e. to field-coil speakers):
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EIA Speaker Color Code

Voice-coil:
Green - finish
Black - start

Field Coils:
Black and red - start
Yellow and red - finish
Slate and red - tap (if any)

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EIA Wiring Color Code

B+ - - - - - - - - - - Red
Ground - - - - - - - - Black
Plate - - - - - - - - Blue
Grid - - - - - - - - - Green
Cathode - - - - - - - Yellow
High Heater - - - - - Brown
Low Heater - - - - - - Black
Screen Grid - - - - - Orange
AVC - - - - - - - - - White

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EIA Transformer Color Code

IF Transformers:
Blue - - - - - - - - - Plate Lead
Red - - - - - - - - - "B" + Lead
Green - - - - - - - - Grid (or diode) Lead
Black - - - - - - - - Grid (or diode) Return

NOTE: If the secondary of the i.f.t. is center-tapped,
the second diode plate lead is green-and-black striped,
and black is used for the center-tap lead.

Power Transformers:
1. Primary Leads - - - - - - - - - Black
If tapped: Common - - - - - - - Black
Tap - - - - - - - - - - - - - - Black and Yellow striped
Finish - - - - - - - - - - - - Black and Red striped
2. High Voltage Plate Winding - - Red
Center-tap - - - - - - - - - - Red and Yellow striped
3. Rectifier Fil. Winding - - - - Yellow
Center-tap - - - - - - - - - - Yellow and Blue striped
4. Fil. Winding #1 - - - - - - - - Green
Center-tap - - - - - - - - - - Green and Yellow striped
5. Fil. Winding #2 - - - - - - - - Brown
Center-tap - - - - - - - - - - Brown and Yellow striped
6. Fil. Winding #3 - - - - - - - - Slate
Center tap - - - - - - - - - - Slate and Yellow striped

A.F. Transformers:
Blue -- plate (finish) lead of primary
Red -- "B"+ lead (this applies whether the primary is plain
or center-tapped)
Brown -- plate (start) lead on center-tapped primaries (Blue may
be used for this lead if polarity is not important)
Green -- grid (finish) lead to secondary
Black -- grid return (this applies whether the secondary is plain
or center-tapped)
Yellow -- grid (start) lead on center-tapped secondaries (Green may
be used for this lead if polarity is not important)
NOTE: These markings apply also to line-to-grid and tube-to-line
transformers.

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Now the question is, did the mfr. of your piece of gear adhere to the EIA standards!!!