KPA100 with KAT100 in EC enclosure

[Elliott Lawrence]

I have completed the initial construction of the KPA100 and performed the initial tests using the ribbon cable interface.  All of the resistance checks are within tolerance. All of the voltage measurements are within spec except for U1 pin 27 at 3.92 instead of 5.8.  The value of RP1 is 3.9k so it appears that the 8R line is 3.92v.  It isn't obvious that anything is dragging the line down.  All of the interface checks with the K2 are correct.

Any thoughts on a possible problem or is this within acceptable limits?

73
Elliott WA6TLA
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[Don Wilhelm-3]

Elliott,

That voltage appears to be lower than I would expect - but do you have the
KPA100 mounted in the EC2 enclosure with the KAT100 or are you connecting
the ribbon cable directly to the K2?

You may want to check the continuity on the 8R signal as it comes from the
K2 - it should be close to 8 volts at the K2 end.  Your 'almost 4 volts'
reading will likely work OK, since the KPA100 microprocessor appears to use
this only as a digital signal, and the important thing is that it be high
enough to avoid noise problems on the signal line (and the resulting false
detection of a low state) - so check the resistance of the 8R signal from
the K2 to the KPA100 (you should expect a low value) - if the resistance is
substantial, check your cables and connections carefully.

73,
Don W3FPR

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]]On Behalf Of Elliott Lawrence
> Sent: Monday, May 29, 2006 6:21 PM
> To: Elecraft List
> Subject: [Elecraft] KPA100 with KAT100 in EC enclosure
>
>
> I have completed the initial construction of the KPA100 and
> performed the initial tests using the ribbon cable interface.
> All of the resistance checks are within tolerance. All of the
> voltage measurements are within spec except for U1 pin 27 at 3.92
> instead of 5.8.  The value of RP1 is 3.9k so it appears that the
> 8R line is 3.92v.  It isn't obvious that anything is dragging the
> line down.  All of the interface checks with the K2 are correct.
>
> Any thoughts on a possible problem or is this within acceptable limits?
>
> 73
> Elliott WA6TLA
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
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