11-27-2016, 11:04 AM
I've been trying to increase my understanding of power transformers lately, and in the process began looking at the schematics for a couple of radios I have around here with bad transformers in them. The biggest oddball I have is this Stewart Warner 01-SK1 set. It has the dreaded 6X5 tube as a rectifier and a set of 12 volt tubes in the rf/if stages, then a 25 volt tube as output.
The voltages at the rectifier are 160 volts at the plates and 110 volts at the heaters and cathode. The power transformer has three secondary windings, so that would mean one HC with a CT and a winding for the rectifier filaments (is that a 5 volt or what?). The third winding has a tap on it, so one lead in the third winding supplies 25 volts to the output, and the tap supplies...what about 12.5 volts to the rf/if tubes?
That seems really specific, doesn't it? What are the chances that I would ever find a PT with those specs?
I really love the cabinet for this table top radio. It has some inlay copper separating diagonal grained from horizontal grained panels in an almost blonde tone.
The Stewart Warner 01-SK1 schematic: http://www.nostalgiaair.org/pagesbymodel...019838.pdf
The data sheet for the 6X5GT: https://frank.pocnet.net/sheets/127/6/6X5.pdf
The data sheet for the 25L6GT: https://frank.pocnet.net/sheets/093/2/25L6GT.pdf
The voltages at the rectifier are 160 volts at the plates and 110 volts at the heaters and cathode. The power transformer has three secondary windings, so that would mean one HC with a CT and a winding for the rectifier filaments (is that a 5 volt or what?). The third winding has a tap on it, so one lead in the third winding supplies 25 volts to the output, and the tap supplies...what about 12.5 volts to the rf/if tubes?
That seems really specific, doesn't it? What are the chances that I would ever find a PT with those specs?
I really love the cabinet for this table top radio. It has some inlay copper separating diagonal grained from horizontal grained panels in an almost blonde tone.
The Stewart Warner 01-SK1 schematic: http://www.nostalgiaair.org/pagesbymodel...019838.pdf
The data sheet for the 6X5GT: https://frank.pocnet.net/sheets/127/6/6X5.pdf
The data sheet for the 25L6GT: https://frank.pocnet.net/sheets/093/2/25L6GT.pdf
Charlie in San Antonio
