[Elecraft] K2 Build: Voltmeter Probe Assembly help

[Don Wilhelm]

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?
>
>