[Elecraft] Need KXAT1 troubleshooting help

[Don Wilhelm]

Mike,

Well, that is a case where the KX1 microprocessor is not seeing a 
response from the KXAT1 microprocessor.

How are you for digital path troubleshooting?  Have a digital 'scope?  
To troubleshoot in detail is cumbersome.
One thing that you can do is check to be certain the data paths between 
the two microprocessors is intact.  Be certain that is continuity 
between KX1 U1 pin 2 and KXAT1 U1 pin 17.

If your 'scope has a 10X probe on it, you can check at U1 pins 15 and 16 
to see if you can detect 4 MHz oscillation.  If there is none, then 
either the KAT1 firmware chip is defective or the resonator (Z1) is 
defective.  If you do not have a 10X probe, ignore this test because the 
'scope probe can load the circuit and oscillation will cease.

Check the soldering at KXAT1 P3, Z1 and U1, and also at KXAT1 J6 and 
U1.  Make certain the U1 chip is inserted correctly and there are no 
pins bent under the chip (you will have to move the chip up a bit out of 
its socket to see any bent under pins).

73,
Don W3FPR

Mike M wrote:
> I just finished building a KXAT1 for my KX-1.  When I got to the first  
> step of testing, I got "---" in the menu.  I have reseated the IC, and  
> resoldered a few joints that looked a little questionable, but no  
> change in the menu.  It looks ok to me, are there any other tests that  
> I can do to see where the problem is?  Thanks.
>
> 73,
> Mike, KL7MJ
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>