Need KXAT1 troubleshooting help

[Mike M-4]

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:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Mike M-4]

Don -
Thanks. Right after I sent the email I figured it out. I soldered the
IC socket onto the wrong side of the board. Once I got it soldered
onto the correct side of the board it worked perfectly!

This is the second time I've had a problem with ICs that turned out to
be my own fault.

73,
Mike, KL7MJ
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html