Tom,
Yes, that plug offset would have put 12 volts on the VRFDET signal line
into the KAT2, which would most likely fry U1.
You can avoid that problem in the future by 'keying' the P4 and KAT2
plug - remove P4 pin 4 (it is not used) and push a blocking piece of
wire or toothpick into pin 4 of the plug - carefully put a dab of glue
on it if the blocking object is loose. That 'keying' is used for the
ribbon cable for the KPA100 - so if you are not following my words,
download that manual and take a look. With that keying, it is not
possible to plug it incorrectly.
73,
Don W3FPR
On 8/1/2013 1:09 AM, Tom Field wrote:
I was reaching the final stages of installing the KAT2 to my K2. When I
added power, I heard some sizzling and smelled smoke, This didn't happen
with previous power up testing and the build and testing seemed to go
without problems. I noticed that U1 was warm.
Careful inspection showed that when I plugged J8 into the Control Board of
the k2, I inadvertently shifted the plug up one space, causing the wrong
signals/voltage to go down the wire. Corrected that and proceeded to test.
The menu for the ATU appeared without problems and the Ant1/2 cycled on and
off appropriately. When Checking voltage on U4, during TUNE at 5 , I only
get 0.3 to 0.4 volts.
The manual suggests that there is a problem with the build of the SWR
bridge. Will check that, but my question is did I fry U1 and could that be
the cause of what I see?
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