[Elecraft] Re: K2 Transmitter Alignment Problems

[Scheidler, Dale A.]

Serial #5230 is now on the air!  I have repaired the K2 lack of
transmission on half of the bands by replacing the C20 capacitor (47 pf)
on the RF board.  Notes made at the time of initial installation made me
suspect that it may have been faulty.   It puts out good power on all
bands and my 10 meter CW contact last night said it sounded great.  As
per the manual, I am going to wait a bit and learn the radio functions
before installing the other options (ssb, noise blanker, and 160 meter
boards).  The calibration of the 4 MHz master oscillator with the Ft.
Collins time station (10.000.00 MHz) went well.  Prior to this
calibration, the readout was 10.000.17 to dial in this station.  Now the
dial reads 10.000.00.

73,

Dale, kc9cwb 

 

 

Thread-index: 

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Thread-topic: 

K2 Transmitter Alignment Problems

 

 

 

 

I have completed up to page 77 and can get one half of the bands to put

out power.  80, 40, 17, and 15 meters will show power output on the

internal watt meter.  30, 20, 12, and 10 meters will not show power

output.  Adjusting the variable inductors has no effect on wattage

output.  The PA transistors (Q7 and Q8) test good voltages.  What

appears faulty in the RF Board sheet of voltage measurements on page 17

are U4 pin 7 and U5 pin 1.  These test 5 volts and are supposed to test

0 volts.  Pins 7 and 1 are connected to each by looking at the pc board.

Each of these pins is next to a pin on their IC containing 5 volts.

Does this indicate that the problem may likely be a faulty IC?  Q24 is

testing about 75% of the specified at S & D pins while Q18 tests 0 at G

instead of -1.0. I have removed low pass wound filter inductors for two

nonfunctioning bands and reinstalled and this did not correct the

problem on these bands.  I would like to correct myself and not send

away for repair.  Your thoughts would be appreciated.

 

 

 

Thank you,

 

Dale, kc9cwb