Any owner of a Sony ICF-2010/2001D should be aware of the problem involving a blown front-end FET. It is (or at least was) a very common problem for these radios. The problem typically manifests as reduced sensitivity.

I discovered the problem existed in my 2010 when I was with a group of radio enthusiasts and several people were reporting hearing a station I was unable to hear on my radio. Later on, while I was attending an ODXA DX camp, all of the 2010's that had been brought to the camp were tested. It turned out that about half of the 2010's at the camp had a blown front-end FET and the owners of those radios had not been aware of the problem.

Subject: How to detect and fix common Sony 2010 problem
Summary: Fried JFET easily replaced with Radio Shack MPF102

HOW TO DETECT AND REPAIR THE COMMONLY BLOWN TRANSISTOR IN THE SONY 2010

Michael Covington, N4TMI

(Free distribution; you are welcome to copy and distribute this document.)


As is well known, transistor Q303 in the front-end of the Sony ICF-2010
general coverage receiver is easily damaged by static electricity.
Here is information on how to diagnose and fix this problem.

WHAT ARE THE SYMPTOMS?

   A 10- to 20-dB loss of sensitivity on AM (longwave, medium wave, short
   wave). If you have a good antenna you may not even notice the loss.
   In all other respects the radio functions normally.

HOW DO I TEST IT?

   If you buy a used 2010 it's a good idea to perform this test even if you
   do not notice a performance problem.

   Remove the back cover and locate transistor Q303, near the antenna input.
   Identify its three terminals (D, G, and S).

   Now measure the voltage from each of those terminals to ground, with the
   receiver turned on and receiving shortwave.  (A convenient ground connec-
   tion is the outer part of the antenna jack.)

   The voltages should be:  S  0.2V    G 0.0 V    D 2.9 V

   Note especially the drain (D) voltage.  If it is substantially lower than
   2.9V, the transistor is leaky.  (Mine measured 1.6V when defective.)
   If it's substantially higher (like 4.5V), the transistor is open.

HOW DO I FIX IT?

   The popular MPF-102 transistor, available at Radio Shack, is a suitable
   replacement.  (Sony used a 2SK152, not widely available in the U.S.A.)
   Simply unsolder the old transistor and install the new one, then check
   voltages again.   No alignment is necessary.

HOW DO I PREVENT FURTHER TROUBLE?

   By connecting the shortwave antenna through a protective diode network,
   as shown below.

   \|/ Antenna
    |
    +-----------+--------+----------------------------> tip of plug
                |        |
               \ /      ---                                   Sony 2010
               ---      / \      Four 1N914 or                antenna
                |        |       1N4148 diodes                jack
               \ /      ---      (do not substitute)
               ---      / \
                |        |
    +-----------+--------+----------------------------> sleeve of plug
    |
 -------
  -----
   --- Ground (optional)

    The diodes limit all voltages going into the receiver.  Use the
    specified types; other kinds would produce loss of signal, signal
    mixing (resulting in image frequencies), or both.

    The 2010 has a built-in protective diode network connected to the
    built-in telescoping antenna but not the antenna jack.
--
==========================================================================
Michael A. Covington, Ph.D. | mcovingt at uga cc uga edu | ham radio N4TMI
Artificial Intelligence Programs | U of Georgia | Athens, GA 30602  U.S.A.
==========================================================================

My thanks to Michael (N4TMI) who sent me an e-mail on January 13, 2008 pointing me to the above information and suggesting I might want to post a copy of it.