[Elecraft] K1 Filter Board Resistance Checks

[Don Wilhelm]

Joe,

First check your meter - does it show zero ohms (or a very very low 
value) when you touch the probes together?

The last two checks indicate the resistance through the low pass filter 
toroids only, did you strip and tin the toroid leads adequately.

If you look at the schematic for the 2 band filter board, you will see 
that the 1st 3 checks should indicate the resistance of the relay coil - 
which is near 270 ohms, and the 4th reading should indicate the value of 
R1.  Do you read 270 ohms between pins 1 and 10 of any of the relays? 
And can you read the resistance of a 100 ohm resistor properly with your 
meter?

Again, look at the schematic and you will see that these are simple 
resistance checks - if the relays are oriented correctly (your photo 
indicates they are, and the soldering is good (can't tell from the 
photos), and your meter is working right, these checks should give the 
expected readings.

73,
Don W3FPR

Joseph M. Durnal wrote:
> I have completed soldering the components for the K1 2 band filter
> board, but when I performed the resistance checks, there was a
> problem.
> 
> XX - U1 pin 6, U1 pin 7 230-270 ohms --- >100k
> XX - U1 pin 6, U1 pin 8 230-270 ohms --- >100k
> XX - U1 pin 6, U1 pin 12 230-270 ohms --- >100k
> XX - U1 pin 13, P2 pin 6 90-110 ohms --- >100k
> OK - P1 pin 1, P1 pin 3 > 100 k
> OK - P1 pin 2, P1 pin 3 > 100 k
> OK - P1 pin 3, P1 pin 4 > 100 k
> OK - P1 pin 3, P1 pin 6 > 100 k
> OK - P2 pin 1, P2 pin 2 > 100 k
> OK - P2 pin 7, P2 pin 8 > 100 k
> XX - K3 pin 2, K3 pin 9 < 5 ohms --- >100k
> XX - K3 pin 4, K3 pin 7 < 5 ohms --- >100k
> 
> Basically, everything that but the P1 & P2 checks seemed well out of
> range, like I have an open somewhere.  I guess an open is better than
> a short!  I took the time to fix some weak looking solder points, but
> that didn't fix it.
> 
> Does anyone on the list have any advice for troubleshooting this?  So
> far, I've thought about trying a different meter :) and as I
> mentioned, fixing up some solder points that didn't look so good.
> 
> High res photos here:
> 
> Bottom
> http://picasaweb.google.com/joseph.durnal/ElecraftK1TransceiverBuild/photo#5063510917493130034 
> 
> 
> Top
> http://picasaweb.google.com/joseph.durnal/ElecraftK1TransceiverBuild/photo#5063510883133391650 
> 
> 
> Thanks to all
> 73
> Joe
> NE3R
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