[Elecraft] K2 S/N 4023 saga

[Rich Haendel]

Continuing saga of S/N 4023. =20

Current consumption steady an all bands at 0.22 amps.=20

1. Ref page 45,  keyer test.  I don't get sidetones when I try and key =
the rig with a keyer (bug).  I AM in CW mode !!.  However when I do the =
menu entry to set sideone, I get control of and hear both the level =
change and the sidetone frequency change, so U8 pins 1 and 4, and Q5 on =
the control board are working.

2.  Checking Q1 and Q2 on the control board.  When I try and key, the =
voltage 8R goes to zero, the voltage for 8T goes high for about 20 =
milliseconds, then drops.   I do hear a blip in the headphones. If I set =
the keyer to HAND, and hold the key down, the DOT/PTT line to pin 29 of =
U6 on the control board goes to zero and stays as long as I hold the key =
down.  U6 pin 27 goes high for about 20 milliseconds and repeats the =
cycle similar to  voltage 8T. =20

3. I've checked the  resistance with power off and voltage 8T is above =
2.5K ohms.=20

4. Voltage checks around U6 and referencing the table on page 15 show =
some differences.=20
Pin 10 should be 5 volts, it is 0 volts
Pin 18 should be 0 volts, it is 5 volts
Pin 25 should be 0 volts, but is 5 volts. =20
Pin 33 should be 5 volts it is 0 volts.=20
Front panel was plugged in and LCD set to CAL FCTR mode from menu as =
indicated.=20

5, I pulled U6 and checked the PC board for shorts to ground and shorts =
to 5 volts on the above pins with the control board out of the rig.  =
everything checks OK.=20

What next anyone?=20

Rich  W3ACO


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