[Elecraft] K2 - signal loss in band-pass filter

[TF3KX]

Interesting.

In my case I never resolved if the MC1350 actually was bad.  I soldered the
entire assembly out of the circuit, but managed to find an original "full
size" chip at a local store, put it in and it simply worked.  So, the
problem - whatever it really was - might have been the same as yours, and
the SMD assembly might have worked if I had put it back into the rig the
second time.

At any rate, good that you are on track, and hope others may learn from
this.  My K2 (#6425) is working perfectly, aside from the fact that my 8V is
low (about 7,56V), and as a result the S-meter can not be calibrated
properly.  I will ask Elecraft to send me a new regulator.

73 and good luck!  - Kristinn, TF3KX


Are LB3SA wrote:
> 
> It was actually one of your earlier posts (thanks!) that prompted me to
> inject the IF signal before and after the IF Amp. At that point I had
> pulled out lot of hair and lost sleep over a low sensitivity K2.
> 
> As to when the solder bridge got there... I'm not 100% certain that a
> bridge was the problem. But after I realized that the IF Amp was not
> amplifying I went over the solder points around the chip (I actually
> removed the chip and installed it again). The radio then started to work.
> It was actually a bit of a surprise since I never saw the problem -
> especially since I looked very closely at all the points through an
> amplifying glass many times before AND since all the voltages at MC1350
> measured at specs while I had the problem. It was just the IF signal that
> wasn't amplifying leading me to at first think that the chip itself was
> defect.
> 
> I only assume it was a solder bridge. And if that's the case it was
> probably made by me.
> 
> Are - LB3SA
> 
> 
> 
> TF3KX wrote:
>> 
>> Just out of curiosity...
>> 
>> Where was that solder bridge on the MC1350?  Was it already on the SMD
>> assembly when you received it, or was it something you caused by your
>> soldering?
>> 
>> The reason I ask is that I had a problem with my SMD MC1350, never found
>> out what caused it, and just replaced it.  If there is something there to
>> watch out for, it may help others...
>> 
>> 73 - Kristinn, TF3KX
>> 
> 
> 

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