Don W3FPR wrote
Gerald,
That certainly sounds like it might be hard to isolate.
I may be wrong, but from the behavior it sounds like you have a relay with
points that are not making good contact - when you put a bit of RF through
it, it becomes OK for a while. Please be aware that this is just
speculation on my part. You may have to work with it a lot to determine
if
it is really fixed. Intermittents are very difficult to troubleshoot.
<snip>
If you can induce the failure and then have it continue while you remove
the
heat sink, you could also check the relay points with a continuity test
between the pins. Check the schematic key for the realy chart and the
schematic itself for the appropriate relay points and pins.
-----------------------------------------------------------------
Gerald,
I agree with Don about a possible problem with relay contacts, I had a relay
problem with my K2 some time ago which caused the receiver's sensitivity on
40m to decrease but which could be restored by either changing the band from
40m and back again, or transmitting a couple of dits. The cause of my
problem was K1's contacts which switch in the 40m bandpass filter,
specifically those of K1A.
With all due respect to Don, making a continuity test might fool you unless
the relay contacts have failed and are not just 'dirty', because the current
from a DMM etc when reading low ohms might be enough to 'clean' a dirty
contact just as a little bit of RF would, but certainly worth trying and
would expose a more severe problem.
If the problem is a 'dirty' contact sometimes the slightest vibration or
movement of the rig / relay can 'cure' the problem - for a very short time.
Since I am obliged to QRT for a several hours, please let me know if you
would like to hear more.
73,
Geoff
GM4ESD
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