[Elecraft] K3 Current Drain When Off

[Stephen Prior]

Not wishing to take this thread too much offf course, but the dollar
equivalent cost of 1 kWh in the UK is about 24 cents US and soon about to
rise and we don't have the most expensive elecrical energy in Europe by a
long way.  So I turn off whatever I can!

73 Stephen G4SJP


On 16 October 2013 22:05, Ken K3IU <kenk3iu at cox.net> wrote:

> 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<elecraft-bounces at mailman.qth.net>
>> [mailto:elecraft-bounces@**mailman.qth.net<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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