Supreme 450 set tester schematic

Iam trying to figure out why diodes are shown

On this schematic where the pin jacks are. They have

Continuity.

Attachments:

• Schematic (296 KB)
• Picture (352 KB)
• Picture chassis (168 KB)
• Picture schematic (108 KB)

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Hello Dave.

Supreme instruments manufactured in the 1920s had the ability to carry out tests on radios by analyzing the valves pins in their actual operation.

I think that the use of the two diodes connected in parallel and in opposite polarity were for circuit protection.

About the continuity you mentioned: when we measure diodes connected in the way shown in the diagram with a multimeter, the "continuity" occurs through one of them...

Take a look at the links below to understand their testing method.

stevenjohnson.com/supreme/freepoint.htm

stevenjohnson.com/supreme/catalog1938page18.htm

Greetings,

Meyer

 

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I dont think diodes small enough to fit in that area were even invented until the 1960s. The diodes back in the day were large and stacked.

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Dear Dave.
The diodes shown in the diagram are... probably the old selenium ones.
But this is just a guess based on what we see in the schematic.
Below is the link for you to download the instruction manual for using this instrument.

stevenjohnson.com/supreme/data/supreme450-manual.pdf

P.S. 

I've never had one of these on hand to examine. That's why we have to draw conclusions with the reference documentation we have available.

Cheers.

Meyer

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