When did Philco switch from cloth to rubber line cords?
Terry
The switch appears to have been made during the 1937 season. Some 1937 Philcos have been found with cloth line cords, but most seem to have rubber.
Did Philco use a standard color code for the chaiss wiring like RMA?
Terry
They did, but I do not remember when they adopted the RMA color codes. I saw that information somewhere, but right now I don't remember where I saw it. I really must be getting old.
Chuck can probably answer this. My copies of
Philco Serviceman are put away right now.
Well, Green was for 6 volt filaments, Yellow was for 5 volt filaments, Red for B+, Grey was for A.C. mains, White was for I.F., yellow was for cathodes, and black was for B- which was sometimes but not always the chassis ground. Striped colors were usually for center taps of power transformers ( on any windings) or bias battery leads, blue and brown were many times output transformer plate connections, and white and purple was reserved for "other." Output transformer secondaries were equally obfuscated, but generally the black was at B- potential or ground, and yellow was 4, green was 8 ohms, and after that it's anyone's guess.
Nobody followed the standards faithfully, and after all those years, most of the colors have faded anyway.
I'm sure someone will come up with a better list, if that helps.
From The Philco Serviceman, May, 1934, p.4
Red......................Filaments and odd wires
Brown...................Cathodes and grounds
White...................B+ and screens of output pentodes
White & Black..........Plates (Wht with blk tracer)
Black & White..........Plates (Blk with wht tracer)
Green....................Grids and screen-grids
This scheme was not strictly adhered to in many following years, it seems and not post-WWII.
Probably valid up through 1936-37 model years, at least.
No revised color codes found in any of the later Serviceman bulletins that I have.
Chuck
Thanks very much for posting this info, Chuck. I for one sincerely appreciate the effort on your part. Saved me a lot of time digging out my copies of
Serviceman. I
knew you'd come through for us!
That's why you pay me the big bucks, Ron! ;)
The binder was handy next to me on the archives shelves.
Igor
Oh! You mean they were colored? All mine have been the same tannish color - yuk, yuk
Well I'm glad we all agree. Just like our old hair, if we have any left , they all are the same color, and we no longer remember what color it was in the first place. When Ling gives me a haircut, I always ask her why she only cuts the white ones.
Just worked on a "modern" guitar amp, and the B+ windings AC windings were red, the 6 volt windings were green, cathode wires were yellow, ground wires were black, primary ac wires were grey, PP outputs were brown and blue, and all the miscellaneous B+ were also red. Miscellaneous was white, and a few purple ones too. Mostly signal and tone control stuff. The acronym NEMA comes to mind, but I'll be d**ned if I remember what it meant.
I just learned I have to stay up another hour until the madman comes to pick up his Pignose Amp. Talk about rework!
So some things live on. Don't rely on it though.
Thanks Chuck!
I still haven't gotten around to pulling out the rf sub chaiss from that 37-675. I was thinking I might do some rewiring at least to the ones that connect from the sub chaiss to other points in the set. Thought I would get some white cloth covered wire from AES and do a little paint job to it. So now I know what colors to whip up.
Terry