Don,
Thanks much for the help. I hope the problem is now fixed.
I learned a lot in the process, both about the inner workings of the
K2 and, more importantly, about troubleshooting intermittent problems.
The culprit (hopefully the only one) was a poorly soldered connection
on RFC1 in the T-R Switch, the lead that connects to C107 and D1.
Thanks again and 73.
John N8ELR
On May 5, 2007, at 5:25 PM, Don Wilhelm wrote:
John,
That certainly sounds like the behavior of an unsoldered connection.
We can trace everything from end to end through the power control
circuits if need be, but for now, look at the schematic and find
the VRFDET signal line and check any components that connect to
that line. Then check the capacitors that you added to the back of
the control board for proper placement and good soldering. The
VPWR and VALC signals are also involved in the power control circuits.
Do you have the basic K2 or do you have the KPA100 attached? How
about a KAT2 or KAT100? Those add circuitry to the power control
loop.
73,
Don W3FPR
John Lamoreaux wrote:
I'm hoping someone can point me in the right direction for
starting to troubleshoot a K2 (no options installed).
I was in the middle of a QSO yesterday, when my power output
started fluctuating. Up to this point, I've had no troubles since
I finished building the rig. It may not be relevant, but I had
just installed a new run of coax. The antenna's SWR showed fine
on my antenna analyzer and on another rig, though.
Here's the situation now. Receive works fine. When I try to
transmit, however, the power out jumps all over the place, way up
or way down, sometimes giving me a high current warning. The
current being drawn is also jumping all over the place.
It is not being caused by a mismatched antenna. The same happens
into a dummy load. A meter connected to the dummy load, by the
way, shows that the actual power out is also fluctuating.
So starting from section 160 of the troubleshooting guide (Power
output fluctuates), I'm not sure where to go next, as the causes
there listed are either the antenna or build errors.
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