[Elecraft] K2 S/N 4023

[Don Wilhelm]

Rich,

Glad you found it was the power supply limiting causing all those
situations.

Check soldering, then check soldering, and finally check soldering!!

Two areas to check first - the output transistors - and the low pass filter
area.  Be certain that the toroid leads were properly tinned.

Then check T1, T2 and T3 for proper number of turns, turns spread correctly,
proper tinning and proper soldering.

One way to check a toroid's leads after it is soldered in is to use the DVM
to read the resistance (it should be zero or VERY close), but do not place
the probe leads directly on the toroid leads, but rather place then at the
edge of the PC board pad.  This gives a first indication of a properly
tinned and soldered toroid (but a first indication only) - you are measuring
the resistance of the wire AND the solder connections too, so placing the
probes directly on the solder will not tell everything one wants to know.  I
have detected several bad solder connections using this technique.

73,
Don W3FPR

----- Original Message ----- 
From: "Rich Haendel" <rhaendel@inav.net>
To: "elecraft reflector" <elecraft@mailman.qth.net>
Sent: Saturday, February 14, 2004 9:39 AM
Subject: [Elecraft] K2 S/N 4023


Continuing Saga of K2 SN 4023
I found out problem about short transmit pulses.  I SENSE was tripping ( U3A
and Q11)  because the 12 volt line was dropping.  My power supply is rated
for 3.6 amps.   I shorted the current sense resistor in my power supply, K2
now display reads Hi Curr,   value is 5.21 amps.  I am not getting the 20
millisecond burst any more.  I get the proper sidetone when I key.  Now I
need to find out why the K2 is drawing so much current.  Power level is set
to 1 watt.  I am continuing

Rich Haendel
W3ACO