[R-390] What gives here!?

[Barry Hauser]

Might be as simple as an outright error.  That was the initial motivation 
behind doing the Y2K book - errors in the originals.

One thing that seems to cause inconsistencies in resistance charts is the 
use of unused tube or connector terminals as convenient tie-points.  In 
addition, because these were arbitrary, they might vary from one batch of 
radios to the next.

Then there's the question of how the resistance and voltage charts were 
compiled -- from a careful read of the (usually early) schematic? -- or live 
readings -- from a prototype?  Either way, there can be errors.

Barry

----- Original Message ----- 
From: "Barry" <n4buq at knology.net>
To: "R-390-List" <R-390 at mailman.qth.net>
Sent: Tuesday, March 07, 2006 10:14 PM
Subject: [R-390] What gives here!?


> Paragraph 56 (page 96) of TM 11-856A shows various table for the 
> resistance
> values for each pin on the various subchassis connectors.  Table "a" is 
> for
> the RF Subchassis and shows the resistance for pin "E" to ground to be
> Inf(inite); however, if I trace the schematic, there are two resistors, 
> R201
> (270K) and R234 (1.5M) in series to GND.  I'm getting about 1.8M so my
> reading agrees with the schematic.
>
> I wonder where they came up with "Inf" for this pin??
>
> Barry - N4BUQ
>
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