[Boatanchors] And Now for Something Competely Different: Zenith

[Glen Zook]

Tubes have been good (others tried with same results) and other components either changed or verified as to value, etc.  Remember, several manufacturers did some "strange" things in circuit design to get around patents, etc., so as not to have to pay royalties and that, in turn, made for some very interesting situations.  The major manufacturers such as Philco, Crosley, and Atwater-Kent had designs that were pretty much straight forward.  But, during the 1920s and 1930s there were quite a number of very small manufacturers and their products ranged from excellent to absolutely dismal in both design and performance.  

I have run into situations where a grid leak resistor was not even included or even no resistor from the cathode to ground, just a bypass capacitor!  In those situations a leaky capacitor would have to exist for the circuit to even think of working!  Proper design?  I think not!  However, the radio did work with the "olde tyme" capacitors.

Many of those companies are referenced in Langley's "Set Catalog and Index" and in the 23 volumes of Rider's (which can be found on the Internet at http://www.nostalgiaair.org/Resources/  )
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: Al Klase <ark at ar88.net>
To: boatanchors at mailman.qth.net 
Sent: Sunday, March 31, 2013 9:08 AM
Subject: Re: [Boatanchors] And Now for Something Competely Different: Zenith
 
I agree with Dennis.  I've recapped many dozen receivers, and I've never seen a problem related to new cap versus old cap as far as bypass and coupling paper caps are concerned.

Glen, can you be more specific about which capacitor?  I'd expect that at the heart of your oscillator problem was another bad component, like a weak tube or an oscillator grid resistor that had aged to a higher value.