K1 2427 operational, but a quick question

I finished K1 #2427 and actually made a contact to Austria with it Friday.
Today I added the KAT1 antenna tuner which seems to work as well (after I
remembered to move the jumper to get the power readings from the tuner...)  
Overall a very nice package, but I have one issue I would appreciate some
advice on. During the voltage checks in the first part of the RF board
assembly:  the voltage on pin 5 of U3 was 3.73, slightly less than the
specified 3.8-4.2 range.  Other voltages were in the lower part of the
specified ranges.  I checked with two different dvm's and got very similar
results, though admittedly neither are high accuracy...  Everything else
looked good, and I decided to continue on.   As I said, the radio worked
perfectly when completed, but should I be worried about the low voltage.

Bernie
W1AZ
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[Mike Morrow-3]

Bernie wrote:

>During the voltage checks in the first part of the RF board
>assembly:  the voltage on pin 5 of U3 was 3.73, slightly less
>than the specified 3.8-4.2 range.

It's all OK and within expected circuit variations.

Pin 5 of U3 is the audio output signal of the AF preamplifier, and there will be variations in the DC voltage levels at that point.  The output of the 8 volt regulator U5 (feeds U3 pin 6) and the strength of input signal (U3 pins 2 and 3) will affect voltages measured elsewhere on U3.

You have no problems.  Enjoy the K1.  Mine is more than seven years old, and it remains my favorite QRP rig of all time.  It's great to see something other than "K3" (especially delivery status report complaints) on the Elecraft list.

73,
Mike / KK5F
K1 SN 175
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