[Collins] 75S-3C power transformer

[Dr.Gerald Johnson]

I don't remember the DA designation for the wire type. A full Collins 
wire designation would have been something like A22PB91 for a 
pvc insulated wire with color code 91 (white with brown stripe). The 
DAS and DA may have applied to some other insulating type or 
thickness. I'm sure the numbers apply to the wire color codes. 1 
being brown, 0 being black, 9 being white, etc. So the DASJ91 
would be white with a brown stripe. DAS912 would be white with 
brown and red stripes (brown stripe wider than the red stripe). 
DA93 would be white with orange stripe, DA902  would be white 
with black and red stripes, DA903 white with black and orange 
stripes, DA905 white with black and green stripes, DA906 white with 
black and blue stripes, DASJ5 would be solid green. DA95 white 
with green stripe.

The transformers themselves have standard RET MA color coding 
for their leads. Primaries typically black and black/white alternating 
for single voltage. High voltage secondary red or red/yellow for the 
center tap. 6 volt heater green, sometimes with a green and a 
second color for the second lead. Green should have never been 
a line color from the transformer, line leads should be black with 
other colors in alternating patterns, but always predominating 
black. 

The turret terminal labels (these were standard turrets from Vector 
Cop) may have been significant but probably were only shown to 
the assembly line workers in their detailed production drawings. 
Then again maybe only the position in the radio was significant and 
the letters were ignored. I don't think they had any automatic way 
of orienting the A terminal in a certain direction so control of which 
lug was used for a particular circuit may have depend on which 
way the lug pointed, not which letter was next to it.

73, Jerry, K0CQ, Technical Advisor to the CRA

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