[Elecraft] Reversed polarity from car-battery

[Don Wilhelm]

Kurt,

The 25 amp circuit breaker is on the rear panel (fan panel), and that 
protects the 100 watt PA.
The remainder of the 12 volt input for the K3 is shown on the schematic 
for the RF Board sheet 3.  There is an RF choke - RFC6, a 6 amp 
resettable fuse - F1,  a zener diode - D28,  and a series protective 
diode - D6 that would be the first things to check. 
Hopefully the zener conducted in the forward direction from the reverse 
voltage and tripped the fuse, and the series diode did its blocking 
function to stop the flow of current into the K3 low power section.  The 
zener may be shorted, and RFC6 may have opened due to the high current.

The KPA3 is not as well protected for reverse voltage, so do hope that 
the circuit breaker tripped in time to prevent further damage.

73,
Don W3FPR

Kurt Wiksten wrote:
> Using my K3 in a portable/mobile operation with the radio connected to the 13.8 car-battery I made a follish misstake
> and reversed the polarity. Result: Dead rig.
> I suppose no one out there have made the same misstake but perhaps someone knows what I should do to get
> the rig back and functioning again. On the block diagram I do only see the 25A ciruit breaker. Is this one self-resetting?
> What might have been damaged??
> Any help is very much appreciated!!
> 73 de Kurt/SM6BGG
>
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