From cbfsb!att!pacbell.com!ames!elroy.jpl.nasa.gov!usc!wupost!uunet!gsm001!gsm Fri Jan 31 10:29:59 EST 1992 Article: 13165 of rec.radio.shortwave Newsgroups: rec.radio.shortwave Path: cbfsb!att!pacbell.com!ames!elroy.jpl.nasa.gov!usc!wupost!uunet!gsm001!gsm From: gsm@mendelson.com (Geoffrey S. Mendelson) Subject: How to reapir your 2010 (reprint) Message-ID: <1992Jan31.022116.1878@mendelson.com> Organization: Mendelson Computer Consulting Date: Fri, 31 Jan 92 02:21:16 GMT The following was posted on 12 Dec 1991 by: nash@ucselx.sdsu.edu (Ron Nash) In article jpd@presto.ig.com.UUCP (Jean-Pierre Dautricourt) writes: >In article <91345.075622AMELMN02@ysub.ysu.edu> AMELMN02@ysub.ysu.edu writes: >>If a 2010 has been attached to a long wire or other bigger outside antenna >>it may have received TOO much signal. There is no protection of the FETs in >>the front end. There are three and when the first one goes you think >>performance is down so you try and feed it more signal. When the second one >>goes the radio becomes VERY deaf. Sony added that external antenna jack as >>an after thought. There is no diode to protect it from signals that are too >>strong. The whip does have a protection diode. End of my input... > >Is there a way to test if any of the FET's are out (besides just suspecting >some performance loss)? Here is how to test and fix your 2010 from my moldy archives. 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 (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 -- ------------------------------------------------------- Michael A. Covington | Artificial Intelligence Programs The University of Georgia | Athens, GA 30602 U.S.A. ------------------------------------------------------- -- Copyright (C) 1992, Geoffrey S. Mendelson. All Rights Reserved. Except for usenet followups, may not be reproduced without permsission. ---------------------------------------------------------------------------- | | Computer Software Consulting | | ---------------------------------------------------------------------------- Geoffrey S. Mendelson Israel geoffrey@mendelson.com or mwcbbs!mailgsm!geoffrey Bust! (215) 242-8712 Looks like August now :-(