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K3 assembly issue

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KJ7SOY

K3 assembly issue

Hi everyone! I’m new to the list and to Elecraft radios and HAM in general. Thanks for bearing with me while I learn!

I picked up an unassembled K3 at an auction three weeks ago. It’s been sitting in a box with most of the boards sealed in their anti-static bags since 2009. I’ve hit a snag and I’m hoping someone here can help.

I have the rev B RF board and I’m doing the manual’s resistance tests. Voltage regulators U12 and U13 are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87 ohms. This unit has never been powered up so I suspect it has to be a bad regulator. I can solder a board just fine and assemble PCB’s but I’m not overly comfortable with hardware debugging. I’ve removed the side cover and checked for loose boards, bad connections, etc. with no success. Anyone have any ideas how I should proceed? Do I just replace the regulator? Do some other debugging?

Thanks!
73
-Adrian
KJ7SOY
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Bill Frantz

Re: K3 assembly issue

When I have had issues like this, I have gotten excellent support from <[hidden email]>.

73 Bill AE6JV

On 2/14/21 at 4:32 PM, [hidden email] (KJ7SOY) wrote:

> I have the rev B RF board and I’m doing the manual’s resistance tests. Voltage regulators U12 and U13
> are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87 ohms. This unit has never been
> powered up so I suspect it has to be a bad regulator. I can solder a board just fine and assemble
> PCB’s but I’m not overly comfortable with hardware debugging. I’ve removed the side cover and checked
> for loose boards, bad connections, etc. with no success. Anyone have any ideas how I should proceed?
> Do I just replace the regulator? Do some other debugging?

---------------------------------------------------------------------------
Bill Frantz | Re IOT: "How many access control systems does it take
www.pwpconsult.com | to change a light bulb?" - Dean Tribble

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Gwen Patton

Re: K3 assembly issue

Just don't scream "ham". It's not an acronym, and there's no reason to put
it in all caps. I have no idea why people keep insisting on capitalizing
it? I know it's off-topic, but why do people do that? Does anyone know?

-=-=-=-=-=-=-=-=-
73,
Gwen, NG3P

On Sun, Feb 14, 2021 at 5:26 PM Bill Frantz <[hidden email]> wrote:

> When I have had issues like this, I have gotten excellent support from <
> [hidden email]>.
>
> 73 Bill AE6JV
>
> On 2/14/21 at 4:32 PM, [hidden email] (KJ7SOY) wrote:
>
> > I have the rev B RF board and I’m doing the manual’s resistance tests.
> Voltage regulators U12 and U13
> > are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87
> ohms. This unit has never been
> > powered up so I suspect it has to be a bad regulator. I can solder a
> board just fine and assemble
> > PCB’s but I’m not overly comfortable with hardware debugging. I’ve
> removed the side cover and checked
> > for loose boards, bad connections, etc. with no success. Anyone have any
> ideas how I should proceed?
> > Do I just replace the regulator? Do some other debugging?
>
> ---------------------------------------------------------------------------
> Bill Frantz | Re IOT: "How many access control systems does it take
> www.pwpconsult.com | to change a light bulb?" - Dean Tribble
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

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Julia Tuttle

Re: K3 assembly issue

Same as "MAC" for the computer, or an urban legend -- they picked it up
somewhere and repeated it and someone else picks it up from them.

On Sun, Feb 14, 2021, 17:31 Gwen Patton <[hidden email]> wrote:

> Just don't scream "ham". It's not an acronym, and there's no reason to put
> it in all caps. I have no idea why people keep insisting on capitalizing
> it? I know it's off-topic, but why do people do that? Does anyone know?
>
> -=-=-=-=-=-=-=-=-
> 73,
> Gwen, NG3P
>
>
> On Sun, Feb 14, 2021 at 5:26 PM Bill Frantz <[hidden email]> wrote:
>
> > When I have had issues like this, I have gotten excellent support from <
> > [hidden email]>.
> >
> > 73 Bill AE6JV
> >
> > On 2/14/21 at 4:32 PM, [hidden email] (KJ7SOY) wrote:
> >
> > > I have the rev B RF board and I’m doing the manual’s resistance tests.
> > Voltage regulators U12 and U13
> > > are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87
> > ohms. This unit has never been
> > > powered up so I suspect it has to be a bad regulator. I can solder a
> > board just fine and assemble
> > > PCB’s but I’m not overly comfortable with hardware debugging. I’ve
> > removed the side cover and checked
> > > for loose boards, bad connections, etc. with no success. Anyone have
> any
> > ideas how I should proceed?
> > > Do I just replace the regulator? Do some other debugging?
> >
> >
> ---------------------------------------------------------------------------
> > Bill Frantz | Re IOT: "How many access control systems does it
> take
> > www.pwpconsult.com | to change a light bulb?" - Dean Tribble
> >
> > ______________________________________________________________
> > 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
> > Message delivered to [hidden email]
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

John Oppenheimer

Re: K3 assembly issue

In reply to this post by KJ7SOY

Hi Adrian, welcome to the hobby and to the Elecraft list,

Wow, that's quite a collector's item! I'd consider asking Elecraft what
they'd charge to assemble and align for you.

John KN5L

On 2/14/21 3:32 PM, KJ7SOY wrote:

> Hi everyone! I’m new to the list and to Elecraft radios and HAM in general. Thanks for bearing with me while I learn!
>
> I picked up an unassembled K3 at an auction three weeks ago. It’s been sitting in a box with most of the boards sealed in their anti-static bags since 2009. I’ve hit a snag and I’m hoping someone here can help.
>
> I have the rev B RF board and I’m doing the manual’s resistance tests. Voltage regulators U12 and U13 are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87 ohms. This unit has never been powered up so I suspect it has to be a bad regulator. I can solder a board just fine and assemble PCB’s but I’m not overly comfortable with hardware debugging. I’ve removed the side cover and checked for loose boards, bad connections, etc. with no success. Anyone have any ideas how I should proceed? Do I just replace the regulator? Do some other debugging?
>
> Thanks!
> 73
> -Adrian
> KJ7SOY

Alan Bloom

Re: K3 assembly issue

Unassembled Heathkits have sold for amazing amounts of money. (I use
the past tense because I doubt there any of those treasures left these
days.)

I have even heard of people "making" an unassembled kit by buying a
built one, taking it apart, unsoldering all the components, and
replacing the soldered parts with new ones. Apparently it is
financially worthwhile to do that. :=)

Alan N1AL

On 2/14/2021 4:20 PM, John Oppenheimer wrote:

> Hi Adrian, welcome to the hobby and to the Elecraft list,
>
> Wow, that's quite a collector's item! I'd consider asking Elecraft what
> they'd charge to assemble and align for you.
>
> John KN5L
>
> On 2/14/21 3:32 PM, KJ7SOY wrote:
>> Hi everyone! I’m new to the list and to Elecraft radios and HAM in general. Thanks for bearing with me while I learn!
>>
>> I picked up an unassembled K3 at an auction three weeks ago. It’s been sitting in a box with most of the boards sealed in their anti-static bags since 2009. I’ve hit a snag and I’m hoping someone here can help.
>>

gt-i

Re: K3 assembly issue

In reply to this post by KJ7SOY

The resistance checks are meant to measure at U13 after being placed and
soldered. It is not a component check, but it will check if you have
done the placement and soldering of all the connected stuff correctly.
IAW, a different value could mean you did a mistake somewhere else.
Visually inspect the boards, solder joints etc before you pull out the
component. In case you already did it, then just test the 7808 outside
of the board. Put 12V to Pin1, GND to Pin 2 and check if you get 8V at
Pin 3.

Happy building,
Gernot DF5RF

Am 14.02.2021 um 22:32 schrieb KJ7SOY:

KJ7SOY

Re: K3 assembly issue

In reply to this post by KJ7SOY

Thanks Gernot. The RF board was already assembled when I bought the unit - I didn’t do any soldering.

I’ve spent two days going through the boards with a fine tooth comb (aka strong magnifier) and I can’t find any solder bridges or poorly seated components. I did wake up with an idea in my head at 3am though, so I have another avenue of attack to try this afternoon.

Thanks for the suggestions everyone! I’ll post when I’ve tested my idea.

73
-Adrian KJ7SOY

> On Feb 16, 2021, at 7:10 AM, [hidden email] wrote:
>
> The resistance checks are meant to measure at U13 after being placed and soldered. It is not a component check, but it will check if you have done the placement and soldering of all the connected stuff correctly. IAW, a different value could mean you did a mistake somewhere else. Visually inspect the boards, solder joints etc before you pull out the component. In case you already did it, then just test the 7808 outside of the board. Put 12V to Pin1, GND to Pin 2 and check if you get 8V at Pin 3.
>
> Happy building,
> Gernot DF5RF
>
>> Am 14.02.2021 um 22:32 schrieb KJ7SOY:
>> Hi everyone! I’m new to the list and to Elecraft radios and HAM in general. Thanks for bearing with me while I learn!
>> I picked up an unassembled K3 at an auction three weeks ago. It’s been sitting in a box with most of the boards sealed in their anti-static bags since 2009. I’ve hit a snag and I’m hoping someone here can help.
>> I have the rev B RF board and I’m doing the manual’s resistance tests. Voltage regulators U12 and U13 are both supposed to test at > 150 ohms. U12 passes but U13 tests at 87 ohms. This unit has never been powered up so I suspect it has to be a bad regulator. I can solder a board just fine and assemble PCB’s but I’m not overly comfortable with hardware debugging. I’ve removed the side cover and checked for loose boards, bad connections, etc. with no success. Anyone have any ideas how I should proceed? Do I just replace the regulator? Do some other debugging?
>> Thanks!
>> 73
>> -Adrian
>> KJ7SOY
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

wa6vab

Re: K3 assembly issue

In reply to this post by Gwen Patton