[amsat-bb] Re: Help needed for my FT-736

Greg D. ko6th_greg at hotmail.com
Mon Feb 14 22:40:27 PST 2011

Yea!  Glad it worked out for you.  

Thanks for following up with the happy ending.


Greg  KO6TH

> To: ko6th_greg at hotmail.com; amsat-bb at amsat.org
> Subject: RE: [amsat-bb]  Help needed for my FT-736
> From: ab4ab at aol.com
> Date: Mon, 14 Feb 2011 23:52:23 -0500
> Greg,
> Finally got to it. Regarding th AF amplifier, indeed, it was the "fuse" 
> 1/4W 1 ohm resistor open circuit. Looked for the email from the VK 
> fellow who had a similar problem and also suggested the "fuse" but 
> could not find it to give him the kudos, hopefully he'll read this post 
> with thanks to him as well. So I'm back in business, in the mean time 
> used an external AF amp as a work around but it's not the same.
> Appreciated the suggestion, thanks.
> 73 de AB4AB
> Ben
> -----Original Message-----
> From: Greg D. <ko6th_greg at hotmail.com>
> To: ab4ab <ab4ab at aol.com>; amsat-bb <amsat-bb at amsat.org>
> Sent: Thu, Sep 9, 2010 3:28 am
> Subject: RE: [amsat-bb]  Help needed for my FT-736
> Hi Ben,
> I haven't looked at the schematic, but I'd be much more suspecting that 
> the cap has shorted out than the OpAmp.  Replace it and the "fuse" and 
> see if that doesn't fix things.  If so, you're lucky.  Usually the $$$ 
> parts go first to save the $.000x ones.
> Greg  KO6TH
> &gt; To: amsat-bb at amsat.org
> &gt; Date: Tue, 31 Aug 2010 18:19:44 -0400
> &gt; From: ab4ab at aol.com
> &gt; Subject: [amsat-bb]  Help needed for my FT-736
> &gt;
> &gt; Hi,
> &gt; My FT-736 suddenly lost all audio (apart from the scanning beep). 
> Looks
> &gt; like the Q06 opamp in the AF Unit failed and shorted out the 
> 1Ω,1/4W
> &gt; resistor (fuse), 13.8V at the supply side, 2.4V at pin 5. Could 
> also be
> &gt; that the 2200μF cap. is shot. I can hear low level noise and 
> signals
> &gt; using an old AF amp. connected to the J02 AF in plug so the rest 
> of the
> &gt; rig incl. the TX appears fine. Any hints how to cure this sick 
> baby
> &gt; will be appreciated. Searched for a NEC μPC2002H replacement but 
> no
> &gt; joy. Found  a possible solution at:
> &gt; http://diyaudioprojects.com/Chip/DIY-TDA2050-Hi-Fi-Chip-Amplifier
> &gt; where the data sheet includes a Single Supply Typical Application
> &gt; Circuit, Fig. 3 in the pdf file @:
> &gt; 
> http://diyaudioprojects.com/Chip/DIY-TDA2050-Hi-Fi-Chip-Amplifier/TDA2050-Datasheet.pdf.
> &gt; Any feedback is welcome, guess Yaesu does not carry any spare 
> boards or
> &gt; spare parts for this old rig.
> &gt; Thanks and 73 de AB4AB
> &gt; Ben
> &gt;
> &gt;
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