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K3 suddenly died

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Lewis Phelps

K3 suddenly died

I'm looking for troubleshooting ideas.

My K3-10 suddenly died while in use. Here's what happened:

I was listening and transmitting on 15 meters. Heard a station in Kansas 5-9 calling into the California QSO Party. I couldn't reach him despite a strong signal from him. SWR 1.1:0 outputting 12 watts.

Beginning to think I was having some kind of problem, I decided to power off the K3 and turn it back on to reset it. When I hit the power switch, the rig shut off with a fairly loud "pop" from the speakers.

Then it wouldn't turn back on at all.

Power supply is fine; 13.98 volts from 50 amp Astron linear supply. Power cable is fine; full voltage at rig end of power cord.

Disconnected all peripherals (speakers, straight key, transverter control cable and RF coax cables to xv432, and mic (Kenwood MC-90 into front panel). Still no joy.

Any suggestions, other than packing it to send to the Mother Ship?

Lew N6LEW

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10
Yaesu FT-7800
[hidden email]
www.ntlew.us

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Lewis Phelps

Re: K3 suddenly died

Belay my last.

K3 resurrected itself after about an hour.

Is this a thermal shutoff issue? What might be the underlying cause?

Lew

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10
Yaesu FT-7800
[hidden email]
www.ntlew.us

On Oct 5, 2013, at 1:16 PM, Lewis Phelps <[hidden email]> wrote:

> I'm looking for troubleshooting ideas.
>
> My K3-10 suddenly died while in use. Here's what happened:
>
> I was listening and transmitting on 15 meters. Heard a station in Kansas 5-9 calling into the California QSO Party. I couldn't reach him despite a strong signal from him. SWR 1.1:0 outputting 12 watts.
>
> Beginning to think I was having some kind of problem, I decided to power off the K3 and turn it back on to reset it. When I hit the power switch, the rig shut off with a fairly loud "pop" from the speakers.
>
> Then it wouldn't turn back on at all.
>
> Power supply is fine; 13.98 volts from 50 amp Astron linear supply. Power cable is fine; full voltage at rig end of power cord.
>
> Disconnected all peripherals (speakers, straight key, transverter control cable and RF coax cables to xv432, and mic (Kenwood MC-90 into front panel). Still no joy.
>
> Any suggestions, other than packing it to send to the Mother Ship?
>
> Lew N6LEW
>
>
>
> Lew Phelps N6LEW
> Pasadena, CA DM04wd
> Elecraft K3-10
> Yaesu FT-7800
> [hidden email]
> www.ntlew.us
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

mikerodgerske5gbc

Re: K3 Suddenly died

In reply to this post by Lewis Phelps

Not to pick on anyone but do I remember wrong?

I've never seen Elecraft recommend running a K3/10 at 12w or a K3/100 at 120.

Maybe I missed it?

I don't this caused the problem but I see this 12/120 pretty frequently.

73
Mike R

m: Lewis Phelps <[hidden email]>
To: "[hidden email] List" <[hidden email]>
Subject: [Elecraft] K3 suddenly died
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

I'm looking for troubleshooting ideas.

My K3-10 suddenly died while in use. Here's what happened:

I was listening and transmitting on 15 meters. Heard a station in Kansas 5-9 calling into the California QSO Party. I couldn't reach him despite a strong signal from him. SWR 1.1:0 outputting 12 watts.

Beginning to think I was having some kind of problem, I decided to power off the K3 and turn it back on to reset it. When I hit the power switch, the rig shut off with a fairly loud "pop" from the speakers.

Then it wouldn't turn back on at all.

Power supply is fine; 13.98 volts from 50 amp Astron linear supply. Power cable is fine; full voltage at rig end of power cord.

Disconnected all peripherals (speakers, straight key, transverter control cable and RF coax cables to xv432, and mic (Kenwood MC-90 into front panel). Still no joy.

Any suggestions, other than packing it to send to the Mother Ship?

Lew N6LEW

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10
Yaesu FT-7800
[hidden email]
www.ntlew.us

Georgia Mules and Country boys are fading fast away
- The Osborne Brothers
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wayne burdick

Re: K3 Suddenly died

Administrator

The K3 can safely be set to its maximum QRP/QRO power levels. If any operating limit is exceeded (temperature, voltage, current drain, SWR, reflected power, etc.), power will automatically be rolled back.

While this protects the radio 99.9% of the time, things can happen -- lightning, ESD, component failure, Acts of God, pet disasters, 8-year-old-boys, etc.

In the present case, some quick resistance or voltage checks might reveal what's going on. Check the Troubleshooting section of the manual, which is pretty extensive and can help you solve most problems. If that doesn't do it, call customer support.

73,
Wayne
N6KR

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mikerodgerske5gbc

Re: K3 Suddenly died

Yes, but what about IMD?

73
Mike R

Georgia Mules and Country boys are fading fast away
- The Osborne Brothers

On Oct 6, 2013, at 12:38 PM, Wayne Burdick <[hidden email]> wrote:

Lewis Phelps

Re: K3 Suddenly died

In reply to this post by wayne burdick

Thanks for input. We can all stand down on this one.

The problem turned out to be a power cable after all.

I was using a 3' power cable assembled with fairly light wire (16 gauge). Over time, the wire had flexed sufficiently at the exit from the APP pin that it began to fray. Fraying let to higher resistance, which led to more voltage drop under load, which led to further decay of the wire-pin joint.

At the point I reported the problem, the power cord was still showing nominal voltage when not connected to the rig. But (apparently) resistance had risen to the point where the K3 wasn't getting sufficient voltage. All this eventually became clear when the wire was completely cooked, broken, and charred on the end.

I shudda tried a different power cord sooner.

Lesson learned: don't use 16 smaller gauge wire with Anderson Power Pole connectors, even if you double the wire to fill up the void in the pin. It's still a single stranded wire where it exits from the pin, and the smaller wire size is more vulnerable to flexing, no matter how low the current demand of the load it's carrying. Eventually, this wire can (and did) become a 1 amp fuse.

73,

Lew N6LEW

PS I don't know the answer to Mike Roger's question about IMD, but I'm willing to bet that the answer is, "not a problem." I trust Elecraft's engineers to pay attention to that sort of thing.

lew

Lew Phelps N6LEW
Pasadena, CA DM04wd
Elecraft K3-10
Yaesu FT-7800
[hidden email]
www.ntlew.us

On Oct 6, 2013, at 10:38 AM, Wayne Burdick <[hidden email]> wrote:

> The K3 can safely be set to its maximum QRP/QRO power levels. If any operating limit is exceeded (temperature, voltage, current drain, SWR, reflected power, etc.), power will automatically be rolled back.
>
> While this protects the radio 99.9% of the time, things can happen -- lightning, ESD, component failure, Acts of God, pet disasters, 8-year-old-boys, etc.
>
> In the present case, some quick resistance or voltage checks might reveal what's going on. Check the Troubleshooting section of the manual, which is pretty extensive and can help you solve most problems. If that doesn't do it, call customer support.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Grant Youngman

Re: K3 Suddenly died

In reply to this post by mikerodgerske5gbc

What about it?

Sent from my iPhone

> On Oct 6, 2013, at 2:28 PM, [hidden email] wrote:
>
> Yes, but what about IMD?
>
> 73
> Mike R
>
> Georgia Mules and Country boys are fading fast away
> - The Osborne Brothers
>
>> On Oct 6, 2013, at 12:38 PM, Wayne Burdick <[hidden email]> wrote:
>>
>> The K3 can safely be set to its maximum QRP/QRO power levels. If any operating limit is exceeded (temperature, voltage, current drain, SWR, reflected power, etc.), power will automatically be rolled back.
>>
>> While this protects the radio 99.9% of the time, things can happen -- lightning, ESD, component failure, Acts of God, pet disasters, 8-year-old-boys, etc.
>>
>> In the present case, some quick resistance or voltage checks might reveal what's going on. Check the Troubleshooting section of the manual, which is pretty extensive and can help you solve most problems. If that doesn't do it, call customer support.
>>
>> 73,
>> Wayne
>> N6KR
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

george fritkin

Re: K3 Suddenly died

In case anybody is interested, electronic equipment does just suddenly fail. Even stuff built by our beloved Elecraft

George, W6GF

________________________________
From: Grant Youngman <[hidden email]>
To: "[hidden email]" <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Sunday, October 6, 2013 1:45 PM
Subject: Re: [Elecraft] K3 Suddenly died

What about it?

Sent from my iPhone

> On Oct 6, 2013, at 2:28 PM, [hidden email] wrote:
>
> Yes, but what about IMD?
>
> 73
> Mike R
>
> Georgia Mules and Country boys are fading fast away
> - The Osborne Brothers
>
>> On Oct 6, 2013, at 12:38 PM, Wayne Burdick <[hidden email]> wrote:
>>
>> The K3 can safely be set to its maximum QRP/QRO power levels. If any operating limit is exceeded (temperature, voltage, current drain, SWR, reflected power, etc.), power will automatically be rolled back.
>>
>> While this protects the radio 99.9% of the time, things can happen -- lightning, ESD, component failure, Acts of God, pet disasters, 8-year-old-boys, etc.
>>
>> In the present case, some quick resistance or voltage checks might reveal what's going on. Check the Troubleshooting section of the manual, which is pretty extensive and can help you solve most problems. If that doesn't do it, call customer support.
>>
>> 73,
>> Wayne
>> N6KR
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:
>
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> Please help support this email list: http://www.qsl.net/donate.html

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Nr4c

Re: K3 Suddenly died

In reply to this post by Lewis Phelps

Well it won't do 120 watts, only goes to 110.

And , page 9 of the manual details the by band output power with a warning that IMD and spurious products are specified at 100 watts. Read between the lines.

...bill nr4c

Sent from my Verizon Wireless 4G LTE DROID

[hidden email] wrote:

>
>Not to pick on anyone but do I remember wrong?
>
>I've never seen Elecraft recommend running a K3/10 at 12w or a K3/100 at 120.
>
>Maybe I missed it?
>
>I don't this caused the problem but I see this 12/120 pretty frequently.
>
>73
>Mike R
>
>
>
>m: Lewis Phelps <[hidden email]>
>To: "[hidden email] List" <[hidden email]>
>Subject: [Elecraft] K3 suddenly died
>Message-ID: <[hidden email]>
>Content-Type: text/plain; charset=us-ascii
>
>I'm looking for troubleshooting ideas.
>
>My K3-10 suddenly died while in use. Here's what happened:
>
>I was listening and transmitting on 15 meters. Heard a station in Kansas 5-9 calling into the California QSO Party. I couldn't reach him despite a strong signal from him. SWR 1.1:0 outputting 12 watts.
>
>Beginning to think I was having some kind of problem, I decided to power off the K3 and turn it back on to reset it. When I hit the power switch, the rig shut off with a fairly loud "pop" from the speakers.
>
>Then it wouldn't turn back on at all.
>
>Power supply is fine; 13.98 volts from 50 amp Astron linear supply. Power cable is fine; full voltage at rig end of power cord.
>
>Disconnected all peripherals (speakers, straight key, transverter control cable and RF coax cables to xv432, and mic (Kenwood MC-90 into front panel). Still no joy.
>
>Any suggestions, other than packing it to send to the Mother Ship?
>
>Lew N6LEW
>
>
>
>Lew Phelps N6LEW
>Pasadena, CA DM04wd
>Elecraft K3-10
>Yaesu FT-7800
>[hidden email]
>www.ntlew.us
>
>
>
>
>
>Georgia Mules and Country boys are fading fast away
> - The Osborne Brothers
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html
>

Gary Gregory-2

Re: K3 Suddenly died

Actually, both outputs are correct. When first released the K3 did go to
120w but was later reduced to 110 by a FW revision which is maintained in
all FW versions from that date if my memory serves me correctly.

In the interest of keeping IMD to a minimum, best practice is to set the k3
output to sub-100w.

The amount of signal loss when using a setting of say 95w is arguably not
to be noticed other than with test equipment.

My AUD 2 cents worth..I get short changed on the exchange rate anyway...:-)

Gary

On 7 October 2013 12:08, bill conkling <[hidden email]> wrote:

> Well it won't do 120 watts, only goes to 110.
>
> And , page 9 of the manual details the by band output power with a warning
> that IMD and spurious products are specified at 100 watts. Read between
> the lines.
>
> ...bill nr4c
>
> Sent from my Verizon Wireless 4G LTE DROID
>
> [hidden email] wrote:
>
> >
> >Not to pick on anyone but do I remember wrong?
> >
> >I've never seen Elecraft recommend running a K3/10 at 12w or a K3/100 at
> 120.
> >
> >Maybe I missed it?
> >
> >I don't this caused the problem but I see this 12/120 pretty frequently.
> >
> >73
> >Mike R
> >
> >
> >
> >m: Lewis Phelps <[hidden email]>
> >To: "[hidden email] List" <[hidden email]>
> >Subject: [Elecraft] K3 suddenly died
> >Message-ID: <[hidden email]>
> >Content-Type: text/plain; charset=us-ascii
> >
> >I'm looking for troubleshooting ideas.
> >
> >My K3-10 suddenly died while in use. Here's what happened:
> >
> >I was listening and transmitting on 15 meters. Heard a station in Kansas
> 5-9 calling into the California QSO Party. I couldn't reach him despite a
> strong signal from him. SWR 1.1:0 outputting 12 watts.
> >
> >Beginning to think I was having some kind of problem, I decided to power
> off the K3 and turn it back on to reset it. When I hit the power switch,
> the rig shut off with a fairly loud "pop" from the speakers.
> >
> >Then it wouldn't turn back on at all.
> >
> >Power supply is fine; 13.98 volts from 50 amp Astron linear supply. Power
> cable is fine; full voltage at rig end of power cord.
> >
> >Disconnected all peripherals (speakers, straight key, transverter control
> cable and RF coax cables to xv432, and mic (Kenwood MC-90 into front
> panel). Still no joy.
> >
> >Any suggestions, other than packing it to send to the Mother Ship?
> >
> >Lew N6LEW
> >
> >
> >
> >Lew Phelps N6LEW
> >Pasadena, CA DM04wd
> >Elecraft K3-10
> >Yaesu FT-7800
> >[hidden email]
> >www.ntlew.us
> >
> >
> >
> >
> >
> >Georgia Mules and Country boys are fading fast away
> > - The Osborne Brothers
> >______________________________________________________________
> >Elecraft mailing list
> >Home: http://mailman.qth.net/mailman/listinfo/elecraft
> >Help: http://mailman.qth.net/mmfaq.htm
> >Post: mailto:[hidden email]
> >
> >This list hosted by: http://www.qsl.net
> >Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

--
*Gary - VK1ZZ
Skype: Gary.VK1ZZ
http://www.qsl.net/vk1zz
Motorhome Portable*
*"Grumpy's House"*
*Elecraft K3
KPA500FT
KAT500FT**

*
______________________________________________________________
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Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Lewis Phelps

When we think of wire gauge requirements for amperage needs, we need to
remember the amperage rating for wire is given for house voltage, typically
~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need larger
wire
size (smaller gauge number). What often saves us is short lead lengths.
Still, if one measures the voltage drop of a conductor under load by using
a DMM with a test lead at each end of the wire, a drop will be seen if the
wire size is not adequate for the load. (Emphasis on 'under load'.)

The voltage drop across a resistance (in this case a conductor) is directly
proportional to the amount of current flow through the resistance. At idle
current, very little voltage drop will be measured in the resistance of the
conductor.

The 12V jack on the back of the radio cannot be used to accurately measure
voltage drop in the power cable, but the voltage measured during key-down
will be approximately 1.4 volts less than the PS voltage if the cable is
good.
An RCA plug can be wired to make the test connections safely.

Dick, n0ce

-----Original Message-----
From: Lewis Phelps
Sent: Sunday, October 06, 2013 2:43 PM
To: [hidden email] List
Subject: Re: [Elecraft] K3 Suddenly died

Thanks for input. We can all stand down on this one.

The problem turned out to be a power cable after all.

I was using a 3' power cable assembled with fairly light wire (16 gauge).
Over time, the wire had flexed sufficiently at the exit from the APP pin
that it began to fray. Fraying let to higher resistance, which led to more
voltage drop under load, which led to further decay of the wire-pin joint.

At the point I reported the problem, the power cord was still showing
nominal voltage when not connected to the rig. But (apparently) resistance
had risen to the point where the K3 wasn't getting sufficient voltage. All
this eventually became clear when the wire was completely cooked, broken,
and charred on the end.

I shudda tried a different power cord sooner.

Lesson learned: don't use 16 smaller gauge wire with Anderson Power Pole
connectors, even if you double the wire to fill up the void in the pin.
It's still a single stranded wire where it exits from the pin, and the
smaller wire size is more vulnerable to flexing, no matter how low the
current demand of the load it's carrying. Eventually, this wire can (and
did) become a 1 amp fuse.

73,

Lew N6LEW

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
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Jim Brown-10

Re: K3 Suddenly died

Nonsense alert!

73, Jim K9YC

On 10/6/2013 10:22 PM, Richard Fjeld wrote:

> When we think of wire gauge requirements for amperage needs, we need to
> remember the amperage rating for wire is given for house voltage,
> typically
> ~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need
> larger wire
> size (smaller gauge number). What often saves us is short lead lengths.
> Still, if one measures the voltage drop of a conductor under load by
> using
> a DMM with a test lead at each end of the wire, a drop will be seen if
> the
> wire size is not adequate for the load. (Emphasis on 'under load'.)
>
> The voltage drop across a resistance (in this case a conductor) is
> directly
> proportional to the amount of current flow through the resistance. At
> idle
> current, very little voltage drop will be measured in the resistance
> of the
> conductor.
>
> The 12V jack on the back of the radio cannot be used to accurately
> measure
> voltage drop in the power cable, but the voltage measured during key-down
> will be approximately 1.4 volts less than the PS voltage if the cable
> is good.
> An RCA plug can be wired to make the test connections safely.

N8MSA

[K3] [P3]For Sale: K3/100 P3/SVGA

In reply to this post by Richard Fjeld

For Sale:

Loaded Elecraft K3/100 and P3/SVGA panadapter. Both are in excellent cosmetic and functional condition.

Below is the complete list of options and filters:
K3/100 - 100w Transceiver Serial Number 4841
KAT3- antenna tuner
KBPF3 - gen coverage bandpass filter
KDVR3 - digital voice recorder
KFL3A-500 - 500 Hz 5-pole filter
KFL3A-6K - 6 kHz 8-pole filter
KFL3B-FM - 13 kHz filter
KFL3A-2.8 2.8 kHz 8-pole filter
KFL3A-1.8 1.8kHz 8-pole filter
KRX3- second receiver with KFL3A-2.7 2.7 kHz 5-pole filter
KTCXO3-1 - TCXO 0.5PPM
KXV3A - K3 RX ant, IF out, Xvtr interface

P3- Panadapter Serial Number 1840
Includes P3-SVGA card.

New cost is $5559; I will sell it for $4050 plus shipping. Willing to demo the radio for anyone willing to drive to my QTH. Payment via cash or cash equivalent (bank check), would rather not use PayPal and am not looking to trade.

Please respond off-list to the email address below.

Thanks for looking and 73,

Mike Alexander - N8MSA

[hidden email]

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Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Richard Fjeld

My comments about using the 12V jack for measuring were directed to a
K3/100.
I should have added that.

-----Original Message-----
From: Richard Fjeld
Sent: Monday, October 07, 2013 12:22 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Suddenly died

When we think of wire gauge requirements for amperage needs, we need to
remember the amperage rating for wire is given for house voltage, typically
~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need larger
wire
size (smaller gauge number). What often saves us is short lead lengths.
Still, if one measures the voltage drop of a conductor under load by using
a DMM with a test lead at each end of the wire, a drop will be seen if the
wire size is not adequate for the load. (Emphasis on 'under load'.)

The voltage drop across a resistance (in this case a conductor) is directly
proportional to the amount of current flow through the resistance. At idle
current, very little voltage drop will be measured in the resistance of the
conductor.

The 12V jack on the back of the radio cannot be used to accurately measure
voltage drop in the power cable, but the voltage measured during key-down
will be approximately 1.4 volts less than the PS voltage if the cable is
good.
An RCA plug can be wired to make the test connections safely.

Dick, n0ce

-----Original Message-----
From: Lewis Phelps
Sent: Sunday, October 06, 2013 2:43 PM
To: [hidden email] List
Subject: Re: [Elecraft] K3 Suddenly died

Thanks for input. We can all stand down on this one.

The problem turned out to be a power cable after all.

I was using a 3' power cable assembled with fairly light wire (16 gauge).
Over time, the wire had flexed sufficiently at the exit from the APP pin
that it began to fray. Fraying let to higher resistance, which led to more
voltage drop under load, which led to further decay of the wire-pin joint.

At the point I reported the problem, the power cord was still showing
nominal voltage when not connected to the rig. But (apparently) resistance
had risen to the point where the K3 wasn't getting sufficient voltage. All
this eventually became clear when the wire was completely cooked, broken,
and charred on the end.

I shudda tried a different power cord sooner.

Lesson learned: don't use 16 smaller gauge wire with Anderson Power Pole
connectors, even if you double the wire to fill up the void in the pin.
It's still a single stranded wire where it exits from the pin, and the
smaller wire size is more vulnerable to flexing, no matter how low the
current demand of the load it's carrying. Eventually, this wire can (and
did) become a 1 amp fuse.

73,

Lew N6LEW

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Scott Manthe-2

Re: K3 Suddenly died

In reply to this post by Jim Brown-10

I know this is the Internet and therefore anything goes, but on this
list, can we at least make an attempt at being polite?

Scott, N9AA

On 10/7/13 2:04 AM, Jim Brown wrote:

> Nonsense alert!
>
> 73, Jim K9YC
>
> On 10/6/2013 10:22 PM, Richard Fjeld wrote:
>> When we think of wire gauge requirements for amperage needs, we need to
>> remember the amperage rating for wire is given for house voltage,
>> typically
>> ~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need
>> larger wire
>> size (smaller gauge number). What often saves us is short lead lengths.
>> Still, if one measures the voltage drop of a conductor under load by
>> using
>> a DMM with a test lead at each end of the wire, a drop will be seen
>> if the
>> wire size is not adequate for the load. (Emphasis on 'under load'.)
>>
>> The voltage drop across a resistance (in this case a conductor) is
>> directly
>> proportional to the amount of current flow through the resistance.
>> At idle
>> current, very little voltage drop will be measured in the resistance
>> of the
>> conductor.
>>
>> The 12V jack on the back of the radio cannot be used to accurately
>> measure
>> voltage drop in the power cable, but the voltage measured during
>> key-down
>> will be approximately 1.4 volts less than the PS voltage if the cable
>> is good.
>> An RCA plug can be wired to make the test connections safely.
>

Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Jim Brown-10

To those who replied on, and off line, I don't mind factual disagreement,
but aren't we above insults? It doesn't get much simpler than this.

R is the resistance of the conductor (wire).
I is the current flow.
E is the Electromotive Force, or voltage.

Ohms law is E=IR, and with simple algebra is I=E/R

If a conductor (wire) is rated for 20 amps at 120 volts for a given length
(due to it's R),
and we want to use that same wire for 20 amps at 13.8 volts,
we must reduce R by either increasing the wire size, decreasing the length,
or a combination of both.

Dick, n0ce

-----Original Message-----
From: Jim Brown
Sent: Monday, October 07, 2013 1:04 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Suddenly died

Nonsense alert!

73, Jim K9YC

On 10/6/2013 10:22 PM, Richard Fjeld wrote:

> When we think of wire gauge requirements for amperage needs, we need to
> remember the amperage rating for wire is given for house voltage,
> typically
> ~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need larger
> wire
> size (smaller gauge number). What often saves us is short lead lengths.
> Still, if one measures the voltage drop of a conductor under load by using
> a DMM with a test lead at each end of the wire, a drop will be seen if the
> wire size is not adequate for the load. (Emphasis on 'under load'.)
>
> The voltage drop across a resistance (in this case a conductor) is
> directly
> proportional to the amount of current flow through the resistance. At
> idle
> current, very little voltage drop will be measured in the resistance of
> the
> conductor.
>
> The 12V jack on the back of the radio cannot be used to accurately measure
> voltage drop in the power cable, but the voltage measured during key-down
> will be approximately 1.4 volts less than the PS voltage if the cable is
> good.
> An RCA plug can be wired to make the test connections safely.

Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Richard Fjeld

Using the 12V out jack for measuring voltage can be used as a fault check of
the
power pole continuity as well. It can remove doubt if test okay.

-----Original Message-----
From: Richard Fjeld
Sent: Monday, October 07, 2013 8:18 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Suddenly died

My comments about using the 12V jack for measuring were directed to a
K3/100.
I should have added that.

-----Original Message-----
From: Richard Fjeld
Sent: Monday, October 07, 2013 12:22 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 Suddenly died

When we think of wire gauge requirements for amperage needs, we need to
remember the amperage rating for wire is given for house voltage, typically
~117 volts AC (in the US). For lower voltage at 13.8 VDC, we need larger
wire
size (smaller gauge number). What often saves us is short lead lengths.
Still, if one measures the voltage drop of a conductor under load by using
a DMM with a test lead at each end of the wire, a drop will be seen if the
wire size is not adequate for the load. (Emphasis on 'under load'.)

The voltage drop across a resistance (in this case a conductor) is directly
proportional to the amount of current flow through the resistance. At idle
current, very little voltage drop will be measured in the resistance of the
conductor.

The 12V jack on the back of the radio cannot be used to accurately measure
voltage drop in the power cable, but the voltage measured during key-down
will be approximately 1.4 volts less than the PS voltage if the cable is
good.
An RCA plug can be wired to make the test connections safely.

Dick, n0ce

-----Original Message-----
From: Lewis Phelps
Sent: Sunday, October 06, 2013 2:43 PM
To: [hidden email] List
Subject: Re: [Elecraft] K3 Suddenly died

Thanks for input. We can all stand down on this one.

The problem turned out to be a power cable after all.

I was using a 3' power cable assembled with fairly light wire (16 gauge).
Over time, the wire had flexed sufficiently at the exit from the APP pin
that it began to fray. Fraying let to higher resistance, which led to more
voltage drop under load, which led to further decay of the wire-pin joint.

At the point I reported the problem, the power cord was still showing
nominal voltage when not connected to the rig. But (apparently) resistance
had risen to the point where the K3 wasn't getting sufficient voltage. All
this eventually became clear when the wire was completely cooked, broken,
and charred on the end.

I shudda tried a different power cord sooner.

Lesson learned: don't use 16 smaller gauge wire with Anderson Power Pole
connectors, even if you double the wire to fill up the void in the pin.
It's still a single stranded wire where it exits from the pin, and the
smaller wire size is more vulnerable to flexing, no matter how low the
current demand of the load it's carrying. Eventually, this wire can (and
did) become a 1 amp fuse.

73,

Lew N6LEW

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Mark Bayern

Re: K3 Suddenly died

In reply to this post by Richard Fjeld

> If a conductor (wire) is rated for 20 amps at 120 volts for a given length
> (due to it's R),

1 -- The voltage rating of a conductor has to do with its insulation.
It has nothing to do with the potential current flow or what you're
calling the wire's "R".

2 -- The applied voltage has no effect on the voltage drop of a
conductor. Look at Ohm's Law again. The voltage drop is due to the
resistance of the conductor (wire) and the current flowing through
that conductor. A conductor with a 2 ohm resistance will have 2 volt
drop when 1 amp flows. That 2 volts is the same for any applied
voltage as long as there is 1 amp flowing. It can be a 12 volt system,
a 120volt system or a 1200 volt system. One amp flowing through a
conductor that has a 2 ohm resistance will have a 2 volt drop.

> ... and we want to use that same wire for 20 amps at 13.8 volts,
> we must reduce R by either increasing the wire size, decreasing the length,
> or a combination of both.

Wrong. If the conductor is good for 20amps it is good for 20amps
_at_any_voltage_. This is probably what activated Jim's "Nonsense
Alert!" beacon.

So ... why use larger conductors at lower voltages? Because for most
uses we want to transfer power. To keep the power the same, we need
more current at lower voltages. Example: A cable that supplies 120
watts at 120Volts needs to conduct 1 amp of current flow. (Power =
current times voltage. P = I * E ). To get the same 120watts from a
12V system you will need 10 amps of current flow. If we tried to use
the same cable at 10 times the current we would have 10 times the
voltage drop. To avoid that we use a larger diameter conductor.

Mark AD5SS
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Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Richard Fjeld

I stated the voltage drop across a resistance (the wire conductor) is
directly proportional to the amount of current flow (amperage) through it.

For a given resistance, as the current increases through it, the voltage
drop increases in it.

Changing the supply voltage will change the current flow through the same
conductor resistance and affect the voltage drop in it.

-----Original Message-----
From: Walter Underwood
Sent: Monday, October 07, 2013 10:20 AM
To: Elecraft Reflector
Subject: Re: [Elecraft] K3 Suddenly died

There is a point which could be made -- the percentage voltage drop is
bigger at 12V than at 120V.

If the voltage drop on your power supply wire is 2V for a given current,
that is the same regardless of the supply voltage. With a 120V supply, the
wire will deliver 118V and with 13.8V it will deliver 11.8V.

So the same voltage drop can matter more at lower supply voltages.

Note that I'm ignoring the difference between AC and DC and skin effect.

wunder
K6WRU

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Richard Fjeld

Re: K3 Suddenly died

In reply to this post by Mark Bayern

Mark,

You said; "If we tried to use the same cable at 10 times the current we
would have 10 times the
voltage drop. To avoid that we use a larger diameter conductor."

Yes!

People interpret statements differently. There is a problem with brevity
on a reflector such as this.
My opening statement of my original post would have been better as this;
Our house wiring codes in my area say that #12 wire can be used for 20 Amp
max (with certain conditions) for 120 Volt circuits.
I said 'typically ~117 volts'. (There are other factors for this rating.)

When I think of 20 amps of current in a 13.8 volt circuit, I first think 12
gauge wire, but if voltage drop is a concern, then it may
be necessary to go with a larger diameter conductor. I mentioned short lead
lengths often save us (from voltage drop).

The real point of my post was how to measure the voltage drop in each
conductor at key-down (load). It seems to have been missed.
You can do this with one DMM lead at the power supply end, and the other
lead at the radio end* for each conductor.
You will measure the actual voltage drop in each conductor, one at a time.
The total drop will be the sum of the two conductor drops.

*For this measurement, the 12V out jack will not show an accurate voltage
drop on each conductor. However, the 12V out jack can be
used for a quick and convenient fault check of the power cable and power
pole connector continuity by measuring the voltage during
key-down at the 12V out jack. I caution folks to wire up a plug for making
fault-free connections to this jack.
My K3/100 at the 12V out jack reads approx. 1.4 volts less than my power
supply voltage with adequate cabling at 100 watts key-down.

Sorry for so much band-width, but it is necessary to avoid
mis-understanding.

Dick, n0ce

-----Original Message-----
From: Mark Bayern
Sent: Monday, October 07, 2013 10:57 AM
To: Richard Fjeld
Cc: [hidden email] ; Elecraft Reflector
Subject: Re: [Elecraft] K3 Suddenly died

> If a conductor (wire) is rated for 20 amps at 120 volts for a given length
> (due to it's R),

1 -- The voltage rating of a conductor has to do with its insulation.
It has nothing to do with the potential current flow or what you're
calling the wire's "R".

2 -- The applied voltage has no effect on the voltage drop of a
conductor. Look at Ohm's Law again. The voltage drop is due to the
resistance of the conductor (wire) and the current flowing through
that conductor. A conductor with a 2 ohm resistance will have 2 volt
drop when 1 amp flows. That 2 volts is the same for any applied
voltage as long as there is 1 amp flowing. It can be a 12 volt system,
a 120volt system or a 1200 volt system. One amp flowing through a
conductor that has a 2 ohm resistance will have a 2 volt drop.

> ... and we want to use that same wire for 20 amps at 13.8 volts,
> we must reduce R by either increasing the wire size, decreasing the
> length,
> or a combination of both.

Wrong. If the conductor is good for 20amps it is good for 20amps
_at_any_voltage_. This is probably what activated Jim's "Nonsense
Alert!" beacon.

So ... why use larger conductors at lower voltages? Because for most
uses we want to transfer power. To keep the power the same, we need
more current at lower voltages. Example: A cable that supplies 120
watts at 120Volts needs to conduct 1 amp of current flow. (Power =
current times voltage. P = I * E ). To get the same 120watts from a
12V system you will need 10 amps of current flow. If we tried to use
the same cable at 10 times the current we would have 10 times the
voltage drop. To avoid that we use a larger diameter conductor.

Mark AD5SS

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