Elecraft

K3 Current Drain When Off

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Rob May-2

Re: K3 Current Drain When Off

Another data point:
K3 1417 measures 4.0 mA when turned off.

Rob
NV5E

> Date: Wed, 16 Oct 2013 21:35:37 -0400
> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Current Drain When Off
>
>
> > I'm measuring with a cute little inline meter that looks at volts,
> > amps, Ah, etc. Called Watts Up. Several ham vendors, including Power
> > Werx, sell it, in the range of $65, with Power Poles on both ends.
>
> I would suspect a display problem with the Watts Up ... like showing
> the wrong range. I *measure* 4.4 mA and 4.2 mA respectively on my K3s
> - s/n 622 and 1450 - with my trusty Fluke 85.
>
> It's either a display problem in the Watts Up or your PAs have problems
> - unplug one wire from the circuit breaker and measure again.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/16/2013 8:42 PM, Jim Brown wrote:
> > On 10/16/2013 2:46 PM, Mike Harris wrote:
> >> FWIW #345 draws 39mA.
> >
> > The two radios I measured are s/n 935 and 1606. They've got a lot of
> > good miles on them. :)
> >
> > I'm measuring with a cute little inline meter that looks at volts, amps,
> > Ah, etc. Called Watts Up. Several ham vendors, including Power Werx,
> > sell it, in the range of $65, with Power Poles on both ends. Bought a
> > second one at Pacificon for $59, tax included.
> >
> > 73, Jim K9YC
> > ______________________________________________________________
> > Elecraft mailing list
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> >
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Jim Brown-10

Re: K3 Current Drain When Off

In reply to this post by wayne burdick

On 10/16/2013 1:33 PM, Wayne Burdick wrote:
> Here's one possible explanation:

Thanks Wayne. Battery voltage is in the range of 12 - 13.8 V, depending
on what the solar panels are doing.

As to residual on accessories -- I've got I/O for the Yankee Clipper
SO2R box plugged into both radios. That has a WinKey emulator, which
feeds the Key input, a paddle which it switches to the paddle input, a
CM500 mic, which it switches to the rear panel input (and for which the
K3 is providing bias), and headphones, switched to the rear panel phones.

I tried unplugging it from one of the radios and nothing changed.

73, Jim K9YC
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tom armour

Re: K3 Current Drain When Off

In reply to this post by Jim Brown-10

Get the one from Hobbyking for $24 instead of from Power Werx. It is the exact same Turnigy 130A meter without the power poles.http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080You can buy a lot of power poles for $40.
73, Tom - wa4ta

> Date: Wed, 16 Oct 2013 17:42:34 -0700
> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Current Drain When Off
>
> On 10/16/2013 2:46 PM, Mike Harris wrote:
> > FWIW #345 draws 39mA.
>
> The two radios I measured are s/n 935 and 1606. They've got a lot of
> good miles on them. :)
>
> I'm measuring with a cute little inline meter that looks at volts, amps,
> Ah, etc. Called Watts Up. Several ham vendors, including Power Werx,
> sell it, in the range of $65, with Power Poles on both ends. Bought a
> second one at Pacificon for $59, tax included.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Bill Frantz

Re: K3 Current Drain When Off

In reply to this post by Jim Brown-10

With my old Fluke 97 in series with the PowerPole input to my
K3/10 (#6299), I saw 0 as the parasitic current. I couldn't even
measure anything on the microamp scale.

When I turned the K3 and P3/SVGA on, the current readings were
much higher on the meter than on the K3 internal meter. (On the
order of 1.8A vs 0.75A.) Turning the P3 off with the front panel
switch reduced the difference to something on the order of 200
milliamps. It sounds like most of the parasitic current is being
drawn by the 100 watt option (or the internal turner).

FWIW, my K3 has the 2M internal transverter and a bunch of
crystal filters as the only significant internal options. (My
XYL, KI6SLX, is giving me the 100 watt internal amp this Christmas.)

Cheers - Bill, AE6JV

On 10/16/13 at 8:06 PM, [hidden email] (Ron D'Eau Claire) wrote:

>I disconnected the PA in my K3 at the circuit breaker and the parasitic
>current from the 13.8V supply dropped from 38mA to nearly zero.
-------------------------------------------------------------------------
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Josh Fiden

Re: K3 Current Drain When Off

In reply to this post by Jim Brown-10

Hi Jim,

A couple of thoughts.... I have a Kill A Watt meter for measuring line
power consumption and discovered it is VERY inaccurate at the low end of
its range. I was measuring an unloaded DC linear supply and at values of
a few mA it was high by a factor of 10 (!) compared to a Fluke 87V. I
haven't used the Watts Up meter, but you might want to check its
accuracy in this range. Also, if the K3 is dissipating 4-5W when powered
off, I'd expect that to be a noticeable amount of heat.

73,
Josh W6XU

On 10/16/2013 5:42 PM, Jim Brown wrote:

> On 10/16/2013 2:46 PM, Mike Harris wrote:
>> FWIW #345 draws 39mA.
>
> The two radios I measured are s/n 935 and 1606. They've got a lot of
> good miles on them. :)
>
> I'm measuring with a cute little inline meter that looks at volts,
> amps, Ah, etc. Called Watts Up. Several ham vendors, including Power
> Werx, sell it, in the range of $65, with Power Poles on both ends.
> Bought a second one at Pacificon for $59, tax included.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>

Geoffrey Downs-3

Re: K3 Current Drain When Off

In reply to this post by Bill Frantz

Re Wayne's possible explanation: My K3 (#266) draws around 39ma when it's
off and the 13.8v psu is on. It seems to be working normally in all
respects. Of course when my K3 is turned off the psu still delivers 13.8v
unless it, too, is turned off so if K3s do not turn off all the way when
there is still voltage on the supply lines it's probably not surprising that
current is still drawn. However, apparently some K3s draw 5ma or less when
off and at least two (Jim K9YC's) a lot more than mine. I am puzzled. Am I
misunderstanding something?

73 to all

Geoff
G3UCK

On October 16 Wayne wrote:

"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."

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Jim Brown-10

Re: K3 Current Drain When Off

In reply to this post by Joe Subich, W4TV-4

On 10/16/2013 6:35 PM, Joe Subich, W4TV wrote:
>
> I would suspect a display problem with the Watts Up ... like showing
> the wrong range. I *measure* 4.4 mA and 4.2 mA respectively on my K3s
> - s/n 622 and 1450 - with my trusty Fluke 85.

You're right, Joe. I pulled out my Fluke and an adapter I had made years
ago for a current probe and measured both radios. Both are drawing 4 mA
when off, about 1.2A when on with one RX, about 1.5A with both RX on.

Thanks for the sanity check.

73, Jim K9YC
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Ralph Parker

Re: K3 Current Drain When Off

In reply to this post by Jim Brown-10

>>I would suspect a display problem with the Watts Up ...

>I pulled out my Fluke and an adapter I had made years ago for a current probe
>and measured both radios. Both are drawing 4 mA when off...

I had a 'current drawn when off' incident a few years ago myself.
K3 'current when off' was over 1 amp when measured with a Watts Up right at
the back of the K3.
The problem turned out to be an anomalous reading on the Watts Up, caused
by an IC-756 ProIII that was running, mounted on the shelf above the K3.
The HV from the display was affecting the reading of the Watts Up. I turned
the Pro3 off, and the reading on the Watts Up dropped to around the 4ma mark.

Ralph, VE7XF

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Jim Brown-10

Re: K3 Current Drain When Off

On 10/18/2013 2:57 PM, Ron D'Eau Claire wrote:
> That only explains the apparent drain of several amperes Jim noticed.

If you're talking about me, the false readings I was getting from the
Watts Up meter were in the range of 40 mA, and a Fluke measured 4 mA in
the positive lead. There may, however, be something happening on the
negative lead that is causing the false readings. I don't have a fixture
yet to put a Fluke there. I should do that.

73, Jim K9YC

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Bill Frantz

Re: K3 Current Drain When Off

When I tried measuring in the negative lead, I found zero amps.
The problem is that the grounding system in my station setup
bypasses the negative lead, probably in several ways, letting me
power the K3 up with no connection to the negative power supply
lead at all.

Cheers - Bill, AE6JV

On 10/18/13 at 4:51 PM, [hidden email] (Jim Brown) wrote:

>If you're talking about me, the false readings I was getting
>from the Watts Up meter were in the range of 40 mA, and a Fluke
>measured 4 mA in the positive lead. There may, however, be
>something happening on the negative lead that is causing the
>false readings. I don't have a fixture yet to put a Fluke
>there. I should do that.
-----------------------------------------------------------------------
Bill Frantz | Concurrency is hard. 12 out | Periwinkle
(408)356-8506 | 10 programmers get it wrong. | 16345
Englewood Ave
www.pwpconsult.com | - Jeff Frantz | Los Gatos,
CA 95032

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Stephen G4SJP

Re: K3 Current Drain When Off

My Fluke 73 reads 4.3mA on the 300mA range and 40mA on the 10A range, which
just goes to show that you can't trust the reading on an instrument when
the 'full scale' value is so very much higher than the current that you are
trying to measure.

73 Stephen G4SJP

On 19 October 2013 07:45, Bill Frantz <[hidden email]> wrote:

> When I tried measuring in the negative lead, I found zero amps. The
> problem is that the grounding system in my station setup bypasses the
> negative lead, probably in several ways, letting me power the K3 up with no
> connection to the negative power supply lead at all.
>
> Cheers - Bill, AE6JV
>
>
> On 10/18/13 at 4:51 PM, [hidden email] (Jim Brown) wrote:
>
> If you're talking about me, the false readings I was getting from the
>> Watts Up meter were in the range of 40 mA, and a Fluke measured 4 mA in the
>> positive lead. There may, however, be something happening on the negative
>> lead that is causing the false readings. I don't have a fixture yet to put
>> a Fluke there. I should do that.
>>
> ------------------------------**------------------------------**
> -----------
> Bill Frantz | Concurrency is hard. 12 out | Periwinkle
> (408)356-8506 | 10 programmers get it wrong. | 16345 Englewood Ave
> www.pwpconsult.com | - Jeff Frantz | Los Gatos, CA 95032
>
>
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Ken Wagner K3IU

Re: K3 Current Drain When Off

In reply to this post by wayne burdick

G'morning, all:

To correct my previous posting, I re-measured the current in
the pos(+) lead again... correctly this time. On a Triplett
2200 DMM, a Radio Shack 22-174B, and a Fluke 77, the reading
is 40-42ma. This is with the KPA3 installed and connected. I
have not opened up the K3 to disconnect the KPA3, but other
postings suggest that the parasitic draw would significantly
drop if I did.

73, Ken K3IU
K3 #202
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On 10/16/2013 5:05 PM, Ken K3IU 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
>>
>>

Ken Wagner K3IU

Re: K3 Current Drain When Off

G'morning, Dave:
My purpose in the posting below was to
correct an error I had made earlier.
You are probably not missing anything,
but IMHO this subject is far more
germane to the purpose of this reflector
than many postings which result in
extraordinarily long lives here.
73, Ken K3IU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On 10/19/2013 7:22 AM, Dave Wright wrote:

> Maybe I'm missing something here, and
> I'm not trying to be a jerk, but we're
> talking about 40ma. Most electronic
> devices these days don't use a "hard"
> power down, but rather a "soft"
> power-off state in order to maintain
> settings/calibration, allow for rapid
> startup/remote control usage, etc.
>
> Elecraft has stated that the K3 will
> draw a minimal amount of power when
> shutdown; although I don't recall that
> they have stated what that amount is;
> so it should be no surprise that the
> K3 is drawing power when shutoff.
>
> It sure seems like there is a lot of
> traffic about something can be solved
> simply by pulling the plug if you're
> worried about breaking the bank over
> 40ma. So, what am I missing?
>
> Dave
> K3DCW
>
> "Real radio bounces off the sky"
>
>
> On Sat, Oct 19, 2013 at 6:09 AM, Ken
> K3IU <[hidden email]
> <mailto:[hidden email]>> wrote:
>
> G'morning, all:
>
> To correct my previous posting, I
> re-measured the current in the
> pos(+) lead again... correctly
> this time. On a Triplett 2200 DMM,
> a Radio Shack 22-174B, and a Fluke
> 77, the reading is 40-42ma. This
> is with the KPA3 installed and
> connected. I have not opened up
> the K3 to disconnect the KPA3, but
> other postings suggest that the
> parasitic draw would significantly
> drop if I did.
>
> 73, Ken K3IU
> K3 #202
>
>

Jim Brown-10

Re: K3 Current Drain When Off

In reply to this post by Bill Frantz

On 10/18/2013 11:45 PM, Bill Frantz wrote:
> When I tried measuring in the negative lead, I found zero amps. The
> problem is that the grounding system in my station setup bypasses the
> negative lead, probably in several ways, letting me power the K3 up
> with no connection to the negative power supply lead at all.

That suggests that the negative terminal is bonded to the chassis in
your DC power supply. There are some good reasons to NOT do that, and
many power supplies are built with DC- not bonded to the chassis. It
also suggests that all the gear in your station is properly bonded
together.

With all equipment bonded together, one might think that the bonding
could carry DC-, and no "black wire" was needed. That's wrong -- while
DC follows Ohm's Law, AC current (and RF) finds the path of lowest
impedance, which includes the loop inductance of a path. So if there
were no black wire, RF would couple into the resulting loop, putting it
on the red wire.

What we fail to realize is that parallel wire cable (like the red/black
glorified zip cord we use for power, and that is sold as speaker cable)
is a sitting duck for RF. Far better to use twisted pair, which has
about 30 dB better RF rejection. I've fixed a lot of RFI to audio system
problems by replacing that zip cord with twisted pair.

73, Jim K9YC

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Jim Brown-10

Re: K3 Current Drain When Off

In reply to this post by Ken Wagner K3IU

Dave,

The reason this matters is that because Wayne comes from the world of
QRP and backpacking, he has always worked very hard to minimize the
current drain on a battery that you have lugged up a mountain (or
charged from solar panels at home). That's one benefit of owning an
Elecraft radio.

I have my SO2R station powered from batteries that are solar charged,
with the addition of an AC charger for contest weekends. All that wiring
is behind an operating desk that is attached to the wall. "Pulling the
plug" on the radios sounds simple, but it means adding a switch to the
DC power line of each radio, in which a design parameter is to minimize
the voltage drop with a 20A load. That means a beefy relay in series
with each radio, and a switch to control it. Now that I know it's a 4mA
drain, I probably won't bother. with 40 mA per radio, I would. :) And
the relay probably draws 50-100 mA when the radios are on.

73, Jim K9YC

On 10/19/2013 4:40 AM, Ken Wagner K3IU wrote:

> G'morning, Dave:
> My purpose in the posting below was to correct an error I had made
> earlier.
> You are probably not missing anything, but IMHO this subject is far
> more germane to the purpose of this reflector than many postings which
> result in extraordinarily long lives here.
> 73, Ken K3IU
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> On 10/19/203 7:22 AM, Dave Wright wrote:
>> Maybe I'm missing something here, and I'm not trying to be a jerk,
>> but we're talking about 40ma. Most electronic devices these days
>> don't use a "hard" power down, but rather a "soft" power-off state in
>> order to maintain settings/calibration, allow for rapid
>> startup/remote control usage, etc.

alsopb

Re: K3 Current Drain When Off

Of course there are car "battery terminal" switches which can handle
100+ amps. They are not expensive. They have insignificant voltage
drop. They draw zero current on or off.

It used to be that having a master power switch for a station was
considered a necessity.
Low voltage stuff these days has somewhat bent that rule. It still
seems like a good idea.

73 de Brian/K3KO

On 10/19/2013 7:11 AM, Jim Brown wrote:

> Dave,
>
> The reason this matters is that because Wayne comes from the world of
> QRP and backpacking, he has always worked very hard to minimize the
> current drain on a battery that you have lugged up a mountain (or
> charged from solar panels at home). That's one benefit of owning an
> Elecraft radio.
>
> I have my SO2R station powered from batteries that are solar charged,
> with the addition of an AC charger for contest weekends. All that
> wiring is behind an operating desk that is attached to the wall.
> "Pulling the plug" on the radios sounds simple, but it means adding a
> switch to the DC power line of each radio, in which a design parameter
> is to minimize the voltage drop with a 20A load. That means a beefy
> relay in series with each radio, and a switch to control it. Now that
> I know it's a 4mA drain, I probably won't bother. with 40 mA per
> radio, I would. :) And the relay probably draws 50-100 mA when the
> radios are on.
>
> 73, Jim K9YC
>
> On 10/19/2013 4:40 AM, Ken Wagner K3IU wrote:
>> G'morning, Dave:
>> My purpose in the posting below was to correct an error I had made
>> earlier.
>> You are probably not missing anything, but IMHO this subject is far
>> more germane to the purpose of this reflector than many postings
>> which result in extraordinarily long lives here.
>> 73, Ken K3IU
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> On 10/19/203 7:22 AM, Dave Wright wrote:
>>> Maybe I'm missing something here, and I'm not trying to be a jerk,
>>> but we're talking about 40ma. Most electronic devices these days
>>> don't use a "hard" power down, but rather a "soft" power-off state
>>> in order to maintain settings/calibration, allow for rapid
>>> startup/remote control usage, etc.
>
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Stephen G4SJP

Re: K3 Current Drain When Off

In reply to this post by Jim Brown-10

Ron,

I'm not sure if your posting was directed at me or not, but I didn't
mentally move the decimal point :-) It was a fundamental limitation of the
(good, I thought) DMM I was using.
It just goes to show that you can't always believe what your measuring
instrument is telling you, as I tell my students frequently!

73, Stephen G4SJP

On 19 October 2013 18:24, Ron D'Eau Claire <[hidden email]> wrote:

> Yes, that was my mistake (mentally moving the decimal point!)
>
> However, several others including me have measured a real parasitic drain
> of
> almost 40 mA (38 mA in my case) that is produced by the KPA3. I
> disconnected
> the power to the KPA3 at the circuit breaker and the drain dropped to
> virtually zero.
>
> The measurement was made by placing an ammeter in the positive lead from
> the
> power supply. Nothing at all connected to the K3 except for the power
> cable.
>
>
> It's not an issue to me because I switch off the dc supply when leaving the
> shack, but there are a significant number of Hams who run from batteries
> and
> solar panels even at home. 40 mA can be very significant to them if the rig
> is left connected to the battery.
>
> 73 Ron AC7AC
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Jim Brown
> Sent: Friday, October 18, 2013 4:52 PM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Current Drain When Off
>
> On 10/18/2013 2:57 PM, Ron D'Eau Claire wrote:
> > That only explains the apparent drain of several amperes Jim noticed.
>
> If you're talking about me, the false readings I was getting from the Watts
> Up meter were in the range of 40 mA, and a Fluke measured 4 mA in the
> positive lead. There may, however, be something happening on the negative
> lead that is causing the false readings. I don't have a fixture yet to put
> a
> Fluke there. I should do that.
>
> 73, Jim K9YC
>
>
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Phil Kane-2

Re: K3 Current Drain When Off

In reply to this post by Stephen G4SJP

On 10/19/2013 1:40 AM, Stephen Prior wrote:

> My Fluke 73 reads 4.3mA on the 300mA range and 40mA on the 10A range, which
> just goes to show that you can't trust the reading on an instrument when
> the 'full scale' value is so very much higher than the current that you are
> trying to measure.

U.S. Federal Communications Commission rules for broadcast station
transmitters (sec. 73.1215) require that the full scale range of a
linear meter be no more than five times the lowest normal indication
being measured, i.e. readings must be more than 20% of full-scale to be
relied upon, and meter accuracy must be greater than 2% of full-scale.

73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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