[Elecraft] K1 Filter Board Test Points ?

[Morrow, Michael A.]

Bill wrote of the KFL1-4:

> Problems with P1,P2,P3 test points.
> 
> P1 pin 1, P1 pin 2 reads 0 (nothing)
> P1 pin 3, P1 pin 4 reads 0
> P2 pin 2, P2 pin 4 reads 1.212 m
> P3 pin 1, P3 pin 3 reads 0
> P3 pin 8, P3 pin 6 reads 0

As Tom noted, it's very hard to tell whether the "0 (nothing)" you report is
meant to tell us whether you mean that a SHORTED (zero ohm) condition is
being shown by your ohm-meter, or an OPEN (infinite or very high ohm)
condition is being shown.

If "0" indicated above actually means you have a OPEN condition between the
test points, then ALL the values you report above are OK except for:

> P1 pin 1, P1 pin 2 reads 0 (nothing)

Here, there should be almost zero ohms (SHORT) shown by your meter.  If not,
then you need to check if there's near zero ohms shown between the PCB
solder pads for the green winding (terminals 1 and 2) on T1.  If there is
instead a high resistance at these two points on the PCB, then you've likely
not adequately removed the insulation from and tinned T1's green leads.  You
should probably make the same checks between the solder pads for the red
windings, then the green windings, on ALL toroids on the PCB.  There should
be a short shown in EVERY case.

On the other hand, if you really really really meant that a short in being
shown with

> P1 pin 3, P1 pin 4 reads 0
> P3 pin 1, P3 pin 3 reads 0
> P3 pin 8, P3 pin 6 reads 0

then you've got some unwanted solder bridges in three different circuits,
and the value you reported with

> P1 pin 1, P1 pin 2 reads 0 (nothing)

is OK.

These are less likely, which is why I think you're actually indicating high
or open resistance rather than the "0" ohms you report.

73,
Mike / KK5F