[amsat-bb] Re: Help needed for my FT-736
ab4ab at aol.com
Mon Feb 14 20:52:23 PST 2011
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
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
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.
> To: amsat-bb at amsat.org
> Date: Tue, 31 Aug 2010 18:19:44 -0400
> From: ab4ab at aol.com
> Subject: [amsat-bb] Help needed for my FT-736
> My FT-736 suddenly lost all audio (apart from the scanning beep).
> like the Q06 opamp in the AF Unit failed and shorted out the
> resistor (fuse), 13.8V at the supply side, 2.4V at pin 5. Could
> that the 2200μF cap. is shot. I can hear low level noise and
> using an old AF amp. connected to the J02 AF in plug so the rest
> rig incl. the TX appears fine. Any hints how to cure this sick
> will be appreciated. Searched for a NEC μPC2002H replacement but
> joy. Found a possible solution at:
> where the data sheet includes a Single Supply Typical Application
> Circuit, Fig. 3 in the pdf file @:
> Any feedback is welcome, guess Yaesu does not carry any spare
> spare parts for this old rig.
> Thanks and 73 de AB4AB
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