[Elecraft] KAT100 General Failure

[Don Wilhelm]

Jonathan,

Yes, replacing KAT100 U1 would be the prudent first step.  But if you 
can, first determine if the resonator Z1 is providing clock pulses to U1 
pins 13 and 14.  Without those clock pulses, U1 will not be functional.

If you have a local ham who also has a KAT100, see if you can swap U1 
from his KAT100 to see if U1 is the problem in yours.

If you do not have a local who is willing to swap, then your best bet is 
to order both the firmware and the resonator from Elecraft.

OTOH, if you have a 4 MHz resonator on hand, try replacing Z1 first to 
see if it comes back to life.  The resonator is inexpensive, but the 
firmware IC is costly.

When the firmware is working, it will be recognized by the K2, 
regardless of any other problems that may be present with the KAT100 
operation.

73,
Don W3FPR

On 1/4/2020 10:49 AM, Jonathan Taylor, K1RFD wrote:
> Thanks Don.
>
> I had the same thought about U1, but unfortunately the symptoms remain
> after re-seating it a couple of times.
>
> Regarding AUXBUS, I believe continuity is good, since a logic probe on
> the KAT100 side shows activity when certain K2 controls are
> manipulated such as Power, Tune, and Band. It is "high" at all other
> times. I checked this all the way to pin 40 of U1.
>
> Should I conclude that the next step would be to replace U1?
>
>