[AMRadio] 2 Meg Multiplier Oddity


Jim Wilhite w5jo at brightok.net
Mon Feb 14 12:50:44 EST 2005


This type of construction of resistors and even capacitors is common in the 
old radios of the 20s and 30s.

73  Jim
W5JO

----- Original Message ----- 
From: "Merz Donald S" <merz.ds at mellon.com>
To: "'Amradio (E-mail)" <amradio at mailman.qth.net>; "'Glowbugs (E-mail)" 
<glowbugs at piobaire.mines.uidaho.edu>
Sent: Monday, February 14, 2005 11:27 AM
Subject: [AMRadio] 2 Meg Multiplier Oddity


> Yesterday, I was replacing a 2 megohm meter multiplier that seemed to have 
> failed. It was a single large-bodied resistor stamped "2M 3.5W". I get it 
> unsoldered and it falls apart in my hands--a cardboard tube with two 
> 2-watt, 1 megohm resistors soldered together in the middle. From the 
> outside, you could not tell that this was 2 resistors in series. It was 
> the connection between them that had failed.
> Very strange.
>
> In replacing this, I was trying to use some resistors from my stock of old 
> ex-mil surplus types. These are usually painted brown and stamped with 
> some specific value--like 681K--on them. Some of these have a construction 
> that has metal end caps attached to the hard body of the resistor (not 
> sure what the body is made of). In many cases, I discovered that when 
> these metal end caps were just gently tugged , they came right off. 
> Clearly, this is another component design that was not engineered to last 
> 50 years.
>
> 73, Don Merz, N3RHT





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