kpa1500 new issue

[Elecraft mailing list]

In the last few days I have made about 21 Qso's with the new amp casually and about 75 Q's in a few contests over the weekend.  The first night I had a problem that seemedto disappear.  It only happened on 40mtrs.  I was xmitting and the power dropped like I went into stby but no indications on the front panel other than the power LED's showinga power drop.  I chalked it up to maybe not having things setup right as it hasn't happened again.
But tonite I was making some 40 mtr Q's and everything looked normal except the temp was jumping from 6 to 8 degrees low, meaning the temp was climbing normally then itwould fluctuate rapidly down about 6 degrees.  If I stopped xmitting the temp was stabile but xmitting it would jump down and back up quickly.  And now as I'm typing this postthe temp has gone down to normal but the same thing is now happening.  Every time I xmit the temp jumps down about 6 degrees and fluctuates back and forth.
I checked on 20 mtrs and it doesn't happen there so either I've got some rf floating around on 40 or there is a problem in the amp.  I ran the power down and it happens all theway down to about 500 watts out but only fluctuates about 4 degrees.  Just checked on 80 and its OK there.  So will look into this tmrw some more.
BillK3WJV
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[Elecraft mailing list]

 Well, I just spoke with Elecraft and it appears this problem was one they had run across in early engineering.  I sent them the config file which might have some indicatorsthey can look at and make some determinations.  But if it turns out to be what the engineer said it might, there might be a fix that is needed to cure this if the temp swing istoo much.
Film at eleven.
BillK3WJV

    On Monday, May 21, 2018, 12:58:37 AM EDT, Bill Stravinsky via Elecraft <[hidden email]> wrote:  
 
 In the last few days I have made about 21 Qso's with the new amp casually and about 75 Q's in a few contests over the weekend.  The first night I had a problem that seemedto disappear.  It only happened on 40mtrs.  I was xmitting and the power dropped like I went into stby but no indications on the front panel other than the power LED's showinga power drop.  I chalked it up to maybe not having things setup right as it hasn't happened again.
But tonite I was making some 40 mtr Q's and everything looked normal except the temp was jumping from 6 to 8 degrees low, meaning the temp was climbing normally then itwould fluctuate rapidly down about 6 degrees.  If I stopped xmitting the temp was stabile but xmitting it would jump down and back up quickly.  And now as I'm typing this postthe temp has gone down to normal but the same thing is now happening.  Every time I xmit the temp jumps down about 6 degrees and fluctuates back and forth.
I checked on 20 mtrs and it doesn't happen there so either I've got some rf floating around on 40 or there is a problem in the amp.  I ran the power down and it happens all theway down to about 500 watts out but only fluctuates about 4 degrees.  Just checked on 80 and its OK there.  So will look into this tmrw some more.
BillK3WJV
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