K2 Build: Voltmeter Probe Assembly help

[Mick Hall]

Hi

I have been progressing through the tests on my K2 build (7587), and have assembled the voltmeter probe as per instructions on page 44 of the manual, and engaged the crimp pin in the upper part of the housing as per the diagram.

When I touch the tinned end of the wire on pin 1 of the I/O controller, U1 on the RF board, I get a reading of zero volts on the K2 LCD. It is meant to be 6V approx.

I have tested with my DMM that their are no breaks in the probe. All other tests, before and after, have been fine up to the start of Assembly Part II .

Is this anything to worry about?

Best Regards
Mick

______________________________________________________________
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]

[Don Wilhelm-4]

Mick,

Since you have a DMM, read the voltage on RF Board U1 pin 1 to ground
with your DMM.  If it is something other than a nominal 6 volts, then
you have a problem with the voltage regulator or something else on the
voltage regulator output.  This is the first step of your testing - make
sure you have a valid voltage there to measure.

If all that is correct, then you can proceed to evaluate the voltage probe.
Make certain the jumper on the P7 header is set to EXT.
Use your DMM (with K2 power off) to measure the resistance between the
probe 'tip' and the center pin of P7 (measure on the back of the Control
Board).  You should see near zero ohms.  If it is not zero, then check
that the crimp pin in the probe is inserted and seated correctly.  Those
crimp pins give many builders trouble.

Then power up the K2 and again touch the 'probe' to RF U1 pin 1.  If it
does not indicate something near 6 volts, check the soldering of CB R9,
R10, U3, and U6 pin 5.

If you do not resolve this problem, then there is a chance that you will
be plagued by "LO BAT" messages.

73,
Don W3FPR


On 2/8/2015 4:37 PM, Mick Hall wrote:

> Hi
>
> I have been progressing through the tests on my K2 build (7587), and have assembled the voltmeter probe as per instructions on page 44 of the manual, and engaged the crimp pin in the upper part of the housing as per the diagram.
>
> When I touch the tinned end of the wire on pin 1 of the I/O controller, U1 on the RF board, I get a reading of zero volts on the K2 LCD. It is meant to be 6V approx.
>
> I have tested with my DMM that their are no breaks in the probe. All other tests, before and after, have been fine up to the start of Assembly Part II .
>
> Is this anything to worry about?
>
>

______________________________________________________________
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]

[Mick Hall]

Hi Don

I feel a little embarrassed about this.

After having built the control board and front board with no issues, I have built kits before and know the pain when placing a component wrongly and then having to remove and replace said component, and being extremely careful not to make this mistake with the K2.
 
This is such a silly mistake, and I only thought about it as I was getting my DMM out, I had noticed before that there is the same component markings on more than one board so I checked again, and sure enough I was plugging the  probe into P5 on the RF board and not the control board.
Voila, 5.9 volts at pin 1 on U1 on the RF board.

I am glad it was such a simple thing.

Again, many thanks for your quick response and my sincere apologies.

Best regards
Mick
--------------------------------------------
On Mon, 9/2/15, Mick Hall <[hidden email]> wrote:

 Subject: Re: [Elecraft] K2 Build: Voltmeter Probe Assembly help
 To: [hidden email]
 Date: Monday, 9 February, 2015, 9:16
 
 Hi Don
 
 Thanks for the quick
 response.
 I will go through these steps this
 evening when I get home from work and let you know how I get
 on.
 
 Regards
 Mick
 --------------------------------------------
 On Sun, 8/2/15, Don Wilhelm <[hidden email]>
 wrote:
 
  Subject: Re: [Elecraft] K2
 Build: Voltmeter Probe Assembly help
  To:
 "Mick Hall" <[hidden email]>,
 [hidden email]
  Date: Sunday, 8 February, 2015, 23:48
 
  Mick,
 
  Since you have a DMM, read the voltage on
 RF
  Board U1 pin 1 to ground
  with your DMM. 
  If it is
 something other than a nominal 6 volts, then
  you have a problem with the voltage
 regulator
  or something else on the
  voltage regulator
  output. 
 This is the first step of your testing - make
  sure you have a valid voltage there to
  measure.
 
  If
 all that is
  correct, then you can proceed
 to evaluate the voltage
  probe.
  Make certain the jumper on the P7
  header is set to EXT.
  Use
 your DMM (with K2
  power off) to measure the
 resistance between the
  probe 'tip'
 and the center pin of P7
  (measure on the
 back of the Control
  Board).  You should
 see near zero ohms.  If
  it is not zero,
 then check
  that the crimp
 
 pin in the probe is inserted and seated correctly. 
 Those
 
  crimp pins give
 many builders trouble.
 
 
 Then power up the K2 and again
  touch the
 'probe' to RF U1 pin 1.  If it
 
 does not indicate something near 6 volts, check
  the soldering of CB R9,
  R10,
 U3, and U6 pin
  5.
 
  If you do not resolve
  this
 problem, then there is a chance that you will
  be plagued by "LO BAT" messages.
 
  73,
  Don
  W3FPR
 
 
  On
  2/8/2015 4:37 PM, Mick
 Hall wrote:
  >
  Hi
  >
  > I have been
  progressing through the tests on my K2 build
 (7587), and
  have assembled the voltmeter
 probe as per instructions on
  page 44 of the
 manual, and engaged the crimp pin in the
 
 upper part of the housing as per the diagram.
  >
  > When I touch the
  tinned end of the wire on pin 1 of the I/O
 controller, U1 on
  the RF board, I get a
 reading of zero volts on the K2 LCD.
  It is
 meant to be 6V approx.
  >
  > I have tested with my DMM that their
 are
  no breaks in the probe. All other
 tests, before and after,
  have been fine up
 to the start of Assembly Part II .
  >
  > Is this anything to
 
 worry about?
  >
  >
 
 
______________________________________________________________
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]