[aprssig] D700 blowing power fuses

Ray Wells vk2tv at exemail.com.au
Thu Jul 19 02:42:18 EDT 2007

Doug Younker wrote:

> Hi Joel,
> Have you disconnected the positive lead at the radio and battery to 
> check to see if there is any continuity from the positive power lead 
> to the vehicle chassis?  There should be none, if there is, follow 
> Matt's advice on, inspecting the harness to the radio or, abandon the 
> one your using and reroute a new one, whatever is easier.  Good Luck
> Doug, N0LKK
> Kansas USA inc.
> Joel Kandel wrote:
>> Has anyone run into the D700 blowing the 20 amp fuse on the positive 
>> power lead to the car battery? All cabling seems to check out until 
>> connected to my D700. Then, in random intervals, the fuse blows. It 
>> doesn't seem to correlate to trasmitting times either. Resistance 
>> measurements on the power leads attached  to the radio with battery 
>> power disconnected seem to swing between "open line" and 30 megohms. 
>> Anyone know what the readings should be with power disconnected?
>> Thanks,
>> Joel Kandel, KI4T
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Joel has already said the problem only happens when the radio is 
connected so that would rule out the wiring to the radio from the battery.

What form of reverse-polarity protection does the radio employ? Is it 
perchance a high-wattage zener that's breaking down due to battery volts 
going too high - read spikes or crook voltage regulator. I don't know 
the radio so am making an educated guess based on servicing experience.

Ray vk2tv

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