[Elecraft] K3: Intermittent Loss of RF Output

2009-10-16 Thread J.A. Wolf, MD, K6JW
Thanks to Stewart and Ignacy for their replies. At least I'm not alone! The 
problem is intermittent and I can go days without its occurrence before, 
suddenly, RF output will abruptly go to zero until I recycle the power or punch 
it in and out of split mode, either of these maneuvers usually solving the 
problem. Because occurrence is so unpredictable, I'm not sure how to 
troubleshoot it. I may need to wait until the problem declares itself more 
consistently. Any other suggestions would be gratefully received. Thanks.
--Jeff, K6JW

**
From Stewart:
Jeff,
Unstable rf power output has often been discussed here. It was a problem in
the early days (I have #145) but in my own experience has now largely
disappeared.  However very occasionally it inexplicably reappears out of the
blue and I'll get a session of unstable output which like stocks and shares
can go up as well as down.
This morning I noticed the display on my Acom 1000 wobbling a bit which is a
sign; just once it suddenly shot up to f/s and then settled back down to
more or less normal. This is the first occurence for literally months. After
so much time I'm convinced it's not hardware/loads or rf getting into the
control circuitry...it's as if the software control has a migraine or
something.
It's never actually been so bad to actually stop me, even early on, so if
your instability is as bad as that on a new build it maybe a
physical/hardware issue. I'm sure the Support crew will help you out there.
Good luck
73.
Stewart Rolfe, GW0ETF

From Ignacy:
There may be many reasons for the same symptom.
In mine, the power decreases intermittently to a very low value, then ERR
TxG appears. It all clears by itself in 5-60 min but then reappears again.
Reinstalling LPA cleared the problem for 2 months but now it is back. I
found recently that the power comes up when when I shake the radio. So it
must be intermittent connection in PRE-LPA stages. Following Gary's advice I
am going to do some troubleshooting but it is not easy because the condition
occurs intermittently.   
Ignacy
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[Elecraft] K3 - Intermittent Loss of RF Output

2009-10-15 Thread J.A. Wolf, MD, K6JW
   I recently completed a K3 kit. All is well except that occasionally and 
unpredictably, RF output drops to zero. This can happen whether I'm operating 
barefoot, driving my Alpha, when simplex, or when split. If simplex, then going 
to split and back to simplex will often result in restoration of RF output, and 
vice versa, i.e., when split, going back to simplex and then split again will 
often help. Cycling the radio's power on and off will resolve the problem 
sometimes, too. This behavior is NOT seen with my other HF radios on the same 
amplifier and antenna system, so it must be something in the K3. Has anyone 
seen this problem and, if so, resolved it? Does anyone have any suggestions 
before I might have to ask the guys at Elecraft to look at it? Thanks in 
advance for any help.
73,
Jeff, K6JW
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