[amsat-bb] Re: FT-847 Disaster - THE PAIN!
donmc at xtra.co.nz
Wed Dec 26 20:41:13 PST 2007
Hi Dave, and the group:
I quite understand your frustration, particularly after what you
probably think you did to cause the problem seems so dumb in retrospect.
Be rest assured you aren't the first and probably not the last to hook
up the power supply leads the wrong way.....being mere humans it's real
easy to do. Other things, like your problem are easily caused as well.
In the commercial world of radio's (R/T) the Tait/Motorola/etc rigs have
all sorts of "idiot proofing" built in....the most useful ones being
FAST blow fuses or circuit breakers combined with a very large (>100
amp) suicide diode in the main power leads to remove power really,
really fast in the event of a major problem.
In all my amateur installations I have included a similar system
utilising high current diodes removed from old car alternators and an
inline fuse rated at only a few amps above the rigs maximum current
requirements, all this placed in the main power line to the rig.
It saved my '817 from instant suicide when I hooked it up in a mates
boat, not realising that it was a 24 volt system. the (5 amp) fuse blew
almost instantly and saved the rig. This system also has a thyristor and
15 volt zener to guard against over voltage since I was told that the
finals can die real fast with over voltage. It (the '817) is still
So I would recommend that a similar system should be provided for ANY
rig that has an external power source, why yaekencom don't do this as a
matter of course is beyond me!
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