[R-390] Resistor Tolerances

Sun, 28 Jul 2002 19:44:59 -0700

Scott -

I assume the resistors used in R-390x's are carbon composition.  Moisture
absorption alone will shift their tolerance up to about +-20%.

When they were more commonly used (20 years ago), I occasionally had to
educate customer incoming inspection departments claiming to have received
"out of tolerance" product with the proper method for measuring the
resistance value of carbon composition resistors.

Among other requirements, before measuring resistance, they must be baked
for a specific period of time at a specific temperature to eliminate
absorbed moisture.

- Greg

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of scott
Sent: Sunday, July 28, 2002 5:32 PM
To: [email protected]
Subject: [R-390] Resistor Tolerances

I got my "A" IF deck recapped today.  Probably half the resistors are more
than 10% high  but less than 20%.  I did not replace any of these.  Does
anyone know if there are any resistors that I should hold to 10% or less?  I
would think that 15%, of which most were, would be OK.
I tried tuning in to 14.283 and BARELY was able to hear mention of
satellites.  I then tuned down to 14.279 and was able to hear nothing.  I
tried this using a SX-71 and a DX-160.  The DX-160 performed better BTW.  So
now I really want to get this "a" back together so I can eavesdrop on future
Sunday afternoons.  :-)

Scott

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