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What type of component is this? - Printable Version

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What type of component is this? - mainewolverine - 09-01-2014

I'm restoring a 1976 Mercury 204 "Drugstore" tube tester. I have a schematic which may be from an earlier model and shows a diode in the circuit where I found this component If this is a diode, I've never seen one like this. Does anyone have any ideas? It tested 1.8M ohm in one direction and 900K ohm in the other direction.

Thanks for any help.

Jim
   
   
   

RE: What type of component is this? - morzh - 09-01-2014

I think it could be a selenium rectifier (yes a diode of a sort).
Plus sign usually denotes the positive out, not the P junction side as in diodes (which would be the negative out).

RE: What type of component is this? - sam - 09-02-2014

whats other side of disc look

RE: What type of component is this? - tab10672 - 09-02-2014

Since it comes apart, I believe it is a button cell battery assembly. Are there any bias voltage symbols in that part of the schematic? Some of the old bias cell symbols look like a modern diode symbol except it should have a + and - on either end.

RE: What type of component is this? - sam - 09-02-2014

that's what I was thinking tab but didn`t what to be ridiculed for saying it looked like a battery in tube radio

RE: What type of component is this? - tab10672 - 09-02-2014

I was shocked to find one in a 37-602 philco. I didn't even know they made batteries that small in 1937 let alone use them in a tube type electronics. Although it looks different than modern button cells (acorn shaped) it is about the same diameter as a watch batt.

RE: What type of component is this? - mainewolverine - 09-02-2014

I've found out that it's a copper oxide rectifier and that they rarely go bad, so I'll put it back together carefully and reinstall.

Thanks for the suggestions.

Jim

RE: What type of component is this? - tab10672 - 09-02-2014

Never heard of those before, learn something new every day. Since they "rarely go bad" it's strange that it would be in an easy access/replaceable assembly.

RE: What type of component is this? - Chuck Schwark - 09-02-2014

The copper oxide alloy is not solderable, hence the spring/clip type connections. Be sure you put the "disc" back in the way it came out
so it matches the polarity marking. ;)

Chuck

RE: What type of component is this? - morzh - 09-02-2014

The selenium elements were not solderable either, they came as bolted assembles with solder lugs,
https://en.m.wikipedia.org/wiki/Selenium_rectifier

or in flat boxes with compartmentalized inside plastic spring loaded holders, that held serialized elements.

http://www.bakersfieldads.net/Algoso-/E250C250-250V-bridge-selenium-rectifier-russia-B250C250.JSP
http://oldradio.onego.ru/COMPS/selen_abc.jpg