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Re: FT-736R power supply

-----Original Message-----
From: JC_Smith@designlink.com <JC_Smith@designlink.com>
To: w4sm@cstone.net <w4sm@cstone.net>
Cc: amsat-bb@AMSAT.Org <amsat-bb@AMSAT.Org>
Date: Thursday, September 16, 1999 8:13 PM
Subject: Re: [amsat-bb] FT-736R power supply

>==== snip ====
>A lot of the Yaesu internal power supplies in FT-736's seem to go bad after
>a few years.  I believe this topic may have been covered here before, but
>is there a usual failure point for these?  Trouble shooting tips, etc.??
>==== snip ====
>If you get any knowledgable replys would you please pass them on?  It has
>definately been covered before, but all I recall hearing were the problems,
>the specific causes or solutions (other that to power from another source,
>which I do).

The issue is apparently a heat problem in which one or more components can
lose a solder joint.  In some of the later models of the transceiver, Yaesu
raised some resistors higher off the PC board to relieve this problem.
However, as a precaution, KD2JF and I installed 80486-type 12V brushless IC
cooling fans on the power supply.  The power supply has a perforated sheet
metal cover to which we bolted the fans.  The air flow should prevent the
excessive heating that could otherwise result from stagnant air in the

Ken Ernandes

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