[Elecraft] Help with K2 recieve troubleshooting

[Don Wilhelm]

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
> 
...