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From cbfsb!att!emory!athena.cs.uga.edu!mcovingt Mon Jul 15 15:45:45 EDT 1991
Article: 8311 of rec.radio.shortwave
Xref: cbfsb rec.radio.shortwave:8311 sci.electronics:17778
Path: cbfsb!att!emory!athena.cs.uga.edu!mcovingt
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: rec.radio.shortwave,sci.electronics
Subject: How I Fixed My Sony 2010
Summary: How to replace FET that commonly fails.
Keywords: Sony 2010 shortwave receiver sensitivity FET
Message-ID: <1991Jul15.044316.2141@athena.cs.uga.edu>
Date: 15 Jul 91 04:43:16 GMT
Organization: University of Georgia, Athens
Lines: 43
(Somebody please save this in an archive somewhere... it's a
frequently asked question.)
The most common component failure in the Sony ICF-2010 (ICF-2001D)
receiver is probably Q303, the AM front end transistor.
The symptom is loss of sensitivity (either sudden, or gradual and
insidious).
In previous net discussion people have said that the failure is due to
static electricity, but mine went kaput while I was using an antenna
well protected by diodes. Personally, I suspect Sony got a bad batch
of transistors.
Anyhow, the repair is easy and does not involve any adjustments or
alignment. Here is the procedure:
(1) Remove the back cover by removing the 7 screws that are marked with
arrows. (One is inside the battery compartment.) Leave the computer
batteries in place.
(2) Locate Q303, which is well marked on the small circuit board near the
antenna jack. The terminals are G(ate), S(ource), and D(rain), in that
order. G is marked.
(3) If you care to make a test, operate the radio in AM mode and measure
the voltage from the drain of Q303, to the sleeve of the antenna jack (which
is circuit ground). If substantially below 2.9V it indicates that Q303 is
leaky.
(4) Replace Q303 with the readily available MPF102 or any other low-noise
N-channel JFET, making sure to get D, S, and G connected correctly.
(5) That's all; put the radio back together and evaluate sensitivity.
73 de N4TMI
--
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Michael A. Covington | Artificial Intelligence Programs
The University of Georgia | Athens, GA 30602 U.S.A.
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