[Elecraft] K3 Current Drain When Off

[Ken K3IU]

Same here but only about 31ma on a Triplett 2202 DMM on K3 
s/n 202.
73, Ken K3IU
~~~~~~~~~~~~~~~~~~~
On 10/16/2013 5:01 PM, Ron D'Eau Claire wrote:
> I disconnected everything from my K3 except the power cable and the drain
> when off remains at 38mA.
>
> I don't have the time right now to pull the PA module, but that sounds like
> the next best possible culprit.
>
> I had never noticed the parasitic drain because my station power supply is
> switched off when I leave the shack.
>
> 73, Ron AC7AC
>
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Wayne Burdick
> Sent: Wednesday, October 16, 2013 1:34 PM
> To: jim at audiosystemsgroup.com
> Cc: Reflector Elecraft
> Subject: Re: [Elecraft] K3 Current Drain When Off
>
> Jim,
>
> Here's one possible explanation:
>
> The external power supply must drop all the way to zero V, as must any all
> K3 I/O signals. This may have implications for attached equipment.
>
> If there's any residual voltage on the supply or I/O lines, even 1 V, the K3
> may not turn off all the way. It turns out that the brown-out detection
> circuitry on microcontrollers can be confused at some power levels that are
> low enough to look like a brownout but not high enough to properly power the
> detection circuitry. Under such conditions the MCU may continue to run on
> power-down via the on/off switch, resulting in the radio drawing an
> unpredictable amount of current.
>
> If residual supply or I/O leakage isn't the cause, then I suspect a problem
> with your K3's on/off circuitry or possibly even the PA module. (You could
> test the latter theory by unplugging the KPA3.) Every K3 we've tested drops
> to a very small number of milliamps of current drain when off.
>
> 73,
> Wayne
> N6KR
>
>   
> Jim Brown <jim at audiosystemsgroup.com> wrote:
>
>> Nope. I measured both units several times, and just now repeated the
> measurements.
>> 73, Jim
>>
>> On 10/16/2013 11:23 AM, Eric Swartz - WA6HHQ, Elecraft wrote:
>>> Hi Jim - you must be misreading the meter by several decimal points :-)
>>>
>>> We just measured several K3s in the lab and they both draw less than 5 mA
> when off.
>>> Eric
>>> elecraft.com
>
>
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