[Boatanchors] A military boatanchor resistor question.

Tue, 27 Apr 2004 20:39:46 -0700

"M" is definately an alternate symbol for "1000".   Like you  I have seen it
on numerous older schematics and context tells you that it is 1000 and not
1,000,000.  Pretty sure that it is tied to the old roman number system in
which "M" was the roman numeral for 1000 (thus the terms millennia and
millenium) and so 50M is 50 * 1000 or 50,000.

Rob

----- Original Message ----- 
From: "John Schmitz" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 27, 2004 7:59 PM
Subject: RE: [Boatanchors] A military boatanchor resistor question.

Phil,
I've noticed this on some schematics as well. I have a schematic of an SX-28
that had the resistors labeled with M and when I compared it to another
schematic of and SX-28, sure enough, every where they had an M should have
been a K. I always thought that it was some type of typo, but now you got me
wondering if there was actually something behind it.

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Philip Atchley
Sent: Tuesday, April 27, 2004 9:01 PM
To: [email protected]
Subject: [Boatanchors] A military boatanchor resistor question.

Hi,
In anticipation of a BC-342 arriving here in the not too distant future,
I've downloaded and printed the military manual on this set (1946).  This is
apparently an "early" version of the set, making it circa 1944.

Today I printed an extra copy of the parts list and am going through the
schematic, hand writing in the values of the capacitors and resistors into
the parts list as it only shows military part numbers.  I expect that I have
most of the capacitors and plan on putting together a "kit" of capacitors
before I dig into the set.  The capacitors haven't proven to be a problem as
I "know" that 100 mmF is actually 100pF (yes, my experience goes back to
"pre-puff" days).

Where I am having a slight problem is in resistors.  There are a lot of them
labeled on the schematic as 50M, 40M, 25M etc.  I am CERTAIN that in this
case "M" DOESN'T stand for MegOhms.  Looking at the locations of these
resistors (grids, screen grids etc) I'd guess that MAYBE a 50M resistor
might actually be a 50K (50,000 Ohms)  resistor, but it could also
conceivably be 500K (500,000 Ohms).

I checked the page in the manual that shows how to read the resistor color
code (something I know by heart) but it said NOTHING about what 40M would
actually mean.  I presume that this is a term that any radio tech of around
1944 would learn in tech-school or Elmers, by the time I came on the scene
in the 50's resistors were already measured in K for K-Ohms or M for
MegOhms.

HELP!
73 from the "Beaconeers Lair".
Phil, KO6BB

DX begins at the noise floor!
Merced, Central California
37.18N  120.29W  CM97sh

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** For Assistance: [email protected] **
$$ For vintage radio info, see the HCI web site $$
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