[Elecraft] K1 Filter Board Test Points ?

[Morrow, Michael A.]

Bill wrote of his KFL1-4:

> P1 pin1, P1 pin2 00.0

...That is a GOOD EXPECTED reading.  Almost a short, as you would expect
through the primary of T1.  All OK!

> P1 pin3, P1 pin4 .0L

...That is a GOOD EXPECTED reading.  Very high resistance, as expected.
Evidently your meter uses ".OL" to show a high-out-of-range reading, which
is what you'd expect between these terminals.  All OK!

> P2 pin2, P2 pin4 1.201

Yesterday you said that this read "1.212 m" (1.2 meg-ohms).  I don't think
you really mean that it's now showing 1.2 ohms.  If you're still getting a
resistance reading above the 10K called for in the manual, then you're all
OK here too!

> P3 pin1, P3 pin3 .0L

...That is a GOOD EXPECTED reading.  Very high resistance, as expected.  All
OK!

> P3 pin8, P3 pin6 .0L

...That is a GOOD EXPECTED reading.  Very high resistance, as expected.  All
OK!

> Sorry, I am new to even multimeters.  My meter comes
> up .oL and indicates a change by showing oo.o why it
> says .oL on some not sure.

".oL" is just showing you that the resistance is too high to measure on your
meter.  Just what you'd expect for an OPEN circuit.  

"00.0" is what it indicates when the resistance is very low.  Just what
you'd expect for a SHORT circuit.

> T1 leads 1,2 read 00.0
> T1 leads 3,4 read 00.0
> T2 leads 1,2 read 00.0
> T2 leads 3,4 read 00.0

GOOD EXPECTED readings...all OK!

> I did a continuity check, 
> T1 leads 1,2 continuity yes.
> T1 leads 3,4 continuity yes.
> note 1,3 or 2,4 continuity no.

Good EXPECTED readings...all OK!

> T2 has a problem.  All combinations show continuity.

As Tom pointed out, the primary and secondary windings of T2 are tied
together to ground, so there's NO problem with your T2 reading.

It looks like **ALL** of your readings are COMPLETELY NORMAL AND EXPECTED!
I don't see any problem, other than interpretation of what your ohm-meter is
telling you.

> A.  I need to buy more toroid wire, do you know where
> I can get a spool of red and green #26.  I think a
> good investment.

It might come in handy for some other reason, but there seems to be no
problems indicated from your data.  If you order some, you'll probably want
to order the type whose painted insulation will come off with the
application of heat.

> B. I should remove U1 before I de-solder.

I don't think you need to de-solder anything.  But if you were to desolder
any KFL1-4 toroid, U1 could stay put since none of the toroid circuits
connect to U1.  

> I tried to remove coating on toroid via solder iron,
> someone told me to use bic lighter, steel wool or fine
> sand paper.

I use the "run the lead through a heated solder blob" method, followed by a
very light scrapping off of the burnt residue with an Exacto knife.  The
last part is tricky, since the smallest knick of the copper conductor can
set you up for lead separation at the knick.

> I just can't pay to have someone build it.  I will learn
> this if it kills me!

Well, it sounds like you've already put the filter board together all OK!
Follow that manual, including doing EXACTLY what it says to do during the
alignment steps, and you'll do fine.

73,
Mike / KK5F