[Elecraft] RE: K1 Output problems

[Mike Morrow]

It sure appears that K5 is stuck in the 20m/17m position.  I'd check closely the soldering connections on the filter board at pins 1 and 8 of relay K5 (the coil), C42, and U1 pin 1 to make sure there are no bridged or open connections.   Check pin 1 on U1 to make sure that pin isn't bent at the socket.  All that would keep K5 from shifting from the 20m/17m position to the 40m/30m position.

Install your filter board and select 40m or 30m, which should latch K5 to the 40m/30m position.  You can then remove the filter board and determine that K5 is NOT in the 40m/30m position by measuring the resistance to ground at K5 pin 4, and again at K5 pin 5.  If the resistance is very high to infinity in each case, then K5 is most likely still in the 20m/17m position.  That also verifies the CN and CP aren't shorted.   A low resistance to ground at pin 2 and pin 7 would also verify that K5 is still in the 20m/17m position.

Measuring resistance from K5 pin 4 to K5 pin 5 when K5 is in the **20m/17m** position and getting high resistance would verify that CK isn't shorted.

If low resistance is measured from K5 pin 4 to ground, that means one or more of the following is true:
1.  K5 is in the 40m/30m position, or
2.  CN is shorted, or
3.  CE is shorted.

If low resistance is measured from K5 pin 5 to ground, that means one or more of the following is true:
1.  K5 is in the 40m/30m position, or
2.  CP is shorted, or
3.  CF is shorted.

But I'd bet my money on the connections associated with the K5 coil, or less likely, a problem with K5 itself.

73,
Mike / KK5F

-----Original Message-----
From: Don Wilhelm <w3fpr at isp.com>
Sent: May 29, 2004 5:35 PM
To: Richard Klingensmith <klingen2 at hotmail.com>, elecraft at mailman.qth.net
Subject: Re: [Elecraft] RE: K1 Output problems

Rick,

Looking at the schematic, there is only a bandpass filter between P2 pin 1
and P2 pin 8.  First check all soldering, then check again, and finally
re-check the soldering - I'd bet you will find the problem.
If there is a bad component, with the behavior that you stated, it must be
something common to 30 and 40 meters that is not used on 20 and 17 meters.
That leaves only Cn, Cp, Ck and the contacts of relay K5 as suspects.  I
doubt that it is the variable caps themselves because they would all have to
fail to give the symptoms you describe.

73,
Don W3FPR

----- Original Message ----- 
>After my late night testing I've started with a little more discipline this
>morning following the Cheap and Dirty Signal Tracing steps. I've found that
>I have a good signal on all bands at P2 pin1. I can also peak the signal on
>all bands in the premix Band-Pass Filter when the signal is injected at P2
>pin1. Now when I move the signal to P2 pin 8 I can peak the signal for 20
>and 18 meters in the RF Band-Pass filter but capacitors CE and CF for 30
>meters and CG and CH for 40 meters do nothing to peak the signal.