[Elecraft] K3 12VDC OUT increased current mod available soon

[Joe Subich, W4TV]

On 3/15/2012 3:13 PM, Wayne Burdick wrote:
> The only easy thing to change in this regard is the 1N4007. It
> probably drops close to a volt, and could be replaced with a 1N5817,
> etc.

That would minimize the drop but is D34 even necessary?  You already
have a shunt diode (D35) across the supply side of the fuse that should
protect the K3 if the user applies negative voltage to the 12V Out.

73,

    ... Joe, W4TV


On 3/15/2012 3:13 PM, Wayne Burdick wrote:
> The only easy thing to change in this regard is the 1N4007. It probably
> drops close to a volt, and could be replaced with a 1N5817, etc. But if
> you want to pull more current, you also have to change the choke and the
> self-resetting fuse. We're working on that.
>
> Wayne
>
> On Mar 15, 2012, at 11:53 AM, Joe Subich, W4TV wrote:
>
>>
>> Instead of simply raising the current limit, you should be addressing
>> the voltage issues as well. With 1.7V (SB530 and 1N4007) of diode
>> drop plus I^2*R losses in two chokes and the switch, the "+12V" is
>> already low (11.8V) with a 13.8V supply. Run the K3 on battery or
>> figure in a typical 0.8V-1.2V sag in the input supply in transmit and
>> the "+12V" output is less than 10.5V.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>> On 3/15/2012 12:18 PM, Paul Saffren N6HZ wrote:
>>> Many of you have asked if there is a way to modify your K3 so that it
>>> can
>>> provide enough current to supply a P3 with the SVGA board. We are
>>> currently
>>> working on a mod kit that will do just that. We'll let you know as
>>> soon as
>>> we have something available.
>>>
>>>
>>> 73,
>>>
>>> Paul (n6hz)
>>>
>>>
>>> --
>>> View this message in context:
>>> http://elecraft.365791.n2.nabble.com/K3-12VDC-OUT-increased-current-mod-available-soon-tp7376146p7376146.html
>>>
>>> Sent from the Elecraft mailing list archive at Nabble.com.
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