[Elecraft] Help with K2 recieve troubleshooting

[Brian]

Don, 

I had some incorrect voltages on D1, D2, and D3.  I reheated the solder from
the top and that fixed my problem.  Everything looks good.  Before I
couldn't hear WWV on 10mhz. Now I'm hearing both stations at 20db over S9.
It may not be perfect yet but It's good enough for now.  

Thank you so much

Brian 
N1WNC


-----Original Message-----
From: Don Wilhelm [mailto:w3fpr at earthlink.net] 
Sent: Monday, April 30, 2007 8:48 PM
To: Brian
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Help with K2 recieve troubleshooting

Brian,

You had a good signal at the junction of D2 and D3, but it dropped 
substantially at the junction of D3 and D4 (and also the remaining 
places closer to the antenna).  That alone should indicate that there is 
a problem with the T/R switch.

First, check the orientation of the diodes - that is most easily done by 
comparing with the parts placement diagram at the back of the manual. 
Of course, remove the heat sink (if it is attached) and check the 
soldering carefully.

Next, refer to the RF Board DC Voltages chart at the back of the manual 
and check the beginning of the leftmost column (D1 thru D7 and Q2).

If you find all the above in proper order, it *should* work (or at least 
you should not still have the severe dropoff in signal between the D2/D3 
junction and the D3/D4 junction).

73,
Don W3FPR

Brian wrote:
> Hello everyone, 
> 
>  
> 
> I am having trouble figuring out where to go next with my troubleshooting.
> Here is what I have so far.  
> 
> I have poor receive on all bands.  The 1st thing I did was check my
> soldering. Then I did the cheap and dirty signal tracing as suggested by
> N0SS.  Here are my results from that.  
> 
> I tuned into a loud broadcast station on 7256 khz.  I was receiving 5 led
> lights with the antenna plugged in normally.  (this station was 60db over
s9
> on my TS-2000)
> 
> Using the recommended probe I got the following:
> 
... SNIP
> 
> 7 RF Board (3 of 4), Jumper W6, input to BPF.
> 
>             9 led lights
> 
> 8 RF Board (3 of 4), junction of D2 & D3, part of the T-R switch
> 
>             9 led lights
> 
> 9 RF Board (3 of 4), junction of D3 & D4, part of the T-R switch
> 
>             Flux from 4-6 led lights
> 
> 10 RF Board (3 of 4), Jumper W1, output of LPF (Low-Pass Filter)
> 
>             5 led lights
> 
> 11 RF Board (3 of 4), C225, wiper of K12a, output of 40M LPF
> 
>             5 led lights
> 
...