[Elecraft] K1 RF board DC checks failing

[Don Wilhelm]

Mike,

U3 pin 6 is the output voltage of the 8 volt regulator - it is lower 
than usual, but not in excess of the regulator specs (+/-10%).  Pin 5 is 
an output from U3 and will depend on the voltage applied to pin 6.
So bottom line - all is OK.

73,
Don W3FPR

Mike Clarke wrote:
> Hi all,
>
> Having received and fitted the replacement voltage regulator that
> solved my previous K1 problem, I've moved on to the first DC checks on
> the RF board (page 30 in my manual.)
>
> I'm performing the checks with the board connected to a stable supply
> at 13.8 volts.
>
> The first two checks pass fine, but the second two state that I should
> be reading between 3.8 and 4.2 volts on U3 pin 5, and between 7.6 and
> 8.7 volts on U3 pin 6.  I'm actually measuring 3.66 volts and 7.54
> volts, respectively.
>
> Normally these might count as 'close enough', but given the quality of
> the manual (and my soldering!) I'm inclined to think I've gone wrong
> somewhere!  Can anyone offer a suggestion as to what I might have
> done?
>   
>