Posts: 136
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Joined: Dec 2016
City: portland, OR
The electrolytics, nos. 60 and 62, on the Rider schematic for Model 37-620 look backwards to me.
http://www.nostalgiaair.org/PagesByModel...013212.pdf
And opposite to those [nos. 66 and 69] on the schematic for the 37-640
http://www.nostalgiaair.org/PagesByModel...013216.pdf
Which is right? Or possibly both?? Or does it matter???
Posts: 755
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Joined: Feb 2013
City: Shenandoah,
State, Province, Country: Pennsylvania
The schematic for the 37-620 electrolytics 60 & 62 are wrong. The schematic for model 37-640 electrolytics 66 & 69 are correct but cap# 66A is wrong. The negative should go to the PT center tap and the positive to chassis ground!
Ron
Bendix 0626. RCA 8BX5. RCA T64
Philco 41-250. Philco49-500
GE 201. Philco 39-25
Motorola 61X13. Philco 46-42 Crosley 52TQ
Philco 37-116. Philco 70
AK 35 Philco 46-350
Philco 620B. Zenith Transoceanic B-600
Philco 60B. Majestic 50
Philco 52-944. AK 84
Posts: 7,215
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
I don't know that I see anything "wrong" with the two different designs. One uses a cap to filter the negative leg of the power. One cost a little more but so does the set.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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City: S. Dartmouth
State, Province, Country: MA
Neither schematic identifies filter capacitor polarity using "+ or -"..
However the "draftsman" uses the symbol of a bar inside of a cup, a symbol intended not only to represent a liquid filled electrolytic but also its polarity, the bar is the "+" and the cup is "-". The wrong schematic has the symbols upside down (connection), not only a polarity error but the electrolyte will run out
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
Posts: 7,215
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
To be honest I don't look at the outside edges or whether it's cupped or not to determine the polarity. They all look like non polarized jobs and I just figure it out.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 18
Threads: 2
Joined: Dec 2021
City: Grafton
State, Province, Country: ON
I can't tell you how many times I have come across this capacitor symbol being incorrectly illustrated in this manner and like Terry, I just find the appropriate ground points and move on but this is the first time that I have seen this pointed out where the misuse of this symbol is also a causing serious secondary violation of the most basic fundamental in physics.
Will have to keep an eye on this moving forward. Thanks Chas, made my day
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City: Roseville, MN
It's such a simple thing to put a plus in the correct place then there's no question to debate.
Great comment on the electrolyte leak, Chas. Good Monday morning pick-me-up.
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Joined: Apr 2018
City: S. Dartmouth
State, Province, Country: MA
It has been so long ago that I serviced a chassis and turned it over to have some of the electrolyte actually run out of the condensers... Yeech...
There was only the smallest standardization of symbols used in schematics. Often a radio brand could be recognized by seeing just a portion of the schematic. RCA had some quirks in early battery sets in using a diagrammatic, then using fillets on lines followed by tube elements numbered within a circle. Tuning condensers often indicating the rotor.
The practice of introducing new symbols as electronics evolved has become more common. Ideally, a "device" schematic should follow a flow of some sort.
For "our" radios signal left to right, impedance high at top and low at bottom of active devices and support (power) feeds under active devices, power sources some lower left some in the lower middle most in lower right.
All that is often confusing when trying to follow signal paths in a diagrammatic, that, is the pictorial of the schematic represented by actual component placement.
In a very recent post in ARF was of a convoluted PA and power supply. More like a corn maze...
https://www.antiqueradios.com/forums/vie...6&t=432631
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
