[Elecraft] KX-1 Q1 Bad - Now no received signal / RF Gain

["RC" KC5WA]

I believe that the J309 is pretty much interchangeable with a J310 or 
MRF102. At least I've done this with no change in other circuits and 
operation did not seem to suffer
"rc" kc5wa

Rich Holoch wrote:

>I had my KX-1 receiver working beautifully through the first 2 stages (up
>through getting the receiver to work), then I added the last components -
>for the transmitter. I turned it on to complete Test III, and there was no
>received signal. Everything but the RF Gain control works. The audio gain
>and  and filter control respond just like before, keyer works, strong
>sidetone and audio, frequency encoder works, bands switch just fine, etc. 
>
> 
>
>I checked all components and sure enough - Q1 was in backwards. I tried to
>unsolder and put it back in, but I am sure it was fried. After putting it in
>correctly, voltage was OK on 2 or the 3 connections - the third was zero
>volts. So the JFET must have opened. 
>
> 
>
>I'm hoping that just by replacing JFET Q1, the receiver will work again. Is
>it possible that by having a bad Q1 that that could cause no signal to be
>detected in the receiver? When I look at the schematic, I almost think that
>the receiver should still work even with Q1 out of the circuit - is this a
>correct or wrong assumption? If it still should work, then there might be
>more wrong than just Q1.
>
> 
>
>Thanks in advance.
>
> 
>
>73,
>
> 
>
>Rich
>
>KY6R
>
> 
>
>P.S - I called my local electronics store and they can't cross reference
>J309 - does anyone know what would cross reference this part number?
>
> 
>
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