[Elecraft] Need K2 troubleshooting suggestions

Thu Dec 12 13:42:00 2002

Thanks to all who shared valuable their valuable advice.  Problem solved.
Since it wasn't identified as one of the many common errors thought you may
want to know what caused this problem.  Once I traced the circuit with the
oscope I found that, sure enough there was about .05v peak-to-peak of BFO
signal on TP2.  Now remember I confirmed that the freq counter and probe
were working by checking TP3 for the VCO signal.  Even could pick up the BFO
freq from U11, so it HAD to be working, right?  I left the probe in TP2 and
unplugged from the control board - stuck the scope probe in the
jack...nuttin.  In the words of that great ancient scholar, Homer - Simpson
that is - DOH!   Yup, the lead had broken off the 10pf cap when I put the
heatshrink on.  Apparently there was enough stray capacitance to couple the
stronger signals to the counter anyway, but it was attenuated enough by the
test point.  So I never had a problem with the BFO after all.  That'll learn
me! :-)

Thanks again and 73
Gil
k1gil

----- Original Message -----
From: "Gil Bishop" <[email protected]>
To: <[email protected]>
Sent: Thursday, December 12, 2002 8:52 AM
Subject: [Elecraft] Need K2 troubleshooting suggestions

> Hello folks.
>
> Assembling K2 #3061 and just hit my first snag.  I'm at Alignment and Test
> Part II and attempting the BFO test.  Connected the internal counter to
TP2
> and got 0000.00.  Figured oscillator wasn't running, but touched the
counter
> probe to end of L33 and got a nice, stable 4913.50.  This all happened too
> late last night to start poking around beyond a cursory check for cold
> solder joints/bridges around the area of the BFO circuit.  My
> troubleshooting skills aren't great, usually tending towards the "shotgun"
> parts replacement approach.  So I was hoping y'all might have some
> suggestions on how you would approach this problem with a more structured
> troubleshooting methodology.  In addition to the internal freq counter, I
> have a DVM and a 50Mhz oscope available.  (Since I have the scope, I
haven't
> built the RF probe assembly but certainly will if it is of value.)  I'll
be
> diving back in tonight...if the XYL isn't too grouchy! hi
>
> Thanks and 73
> Gil
> k1gil
>
>
>
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