[Elecraft] KAT500 tuning problem

[Bill]

For the past month I have been experiencing tuning problems with the 
KAT500.

The antenna in question is a simple 75 meter dipole fed with coax. You 
tune the antenna at 3922, 2955 and 3975 - just for example. When you 
return to those frequencies, a few hours later, the tuning is all off 
and the KPA500 demos its displeasure by beeping and flashing lights. 
Retuning will again hold for a few hours, then all goes haywire again.

I have given shake test to the antenna/halyards -  with an analog SWR 
bridge in line - and see nothing to indicate breaks or damage. I 
replaced the feed line and it still does everything the same. All coax 
lines inside have also been changed out - to no avail.

I should mention that this problem exists on an alternate antenna also. 
The alternate is also a dipole type. No remote baluns, nothing other 
than simple center insulators. Chances are they are built properly - 
been doing it for over 55 years and have never experienced anything like 
this.

I have reset the KAT500 to default a couple of times - reinstalled the 
software - all the things you do with black boxes - went through the 
training thing. I spoken with Elecraft and followed their instructions 
to the letter also (which were the same as what I had been doing). It 
all holds well for a few hours, then goes wacko.

If I have to push the buttons every time I QSY, there is little reason 
to continuing using the KAT500. Of course that makes using the KPA500 
more difficult or impossible.

Shipping is expensive and so are service charges - the tuner is way out 
of warranty.

Anyone have experiences such as these or suggestions?

I am seriously considering regressing to a manual tuner.

Thanks,

Bill W2BLC K-Line