K3 - Intermittent Loss of RF Output

[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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[GW0ETF]

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

J.A. Wolf, MD, K6JW wrote

   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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[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

J.A. Wolf, MD, K6JW wrote

   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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Post: mailto:[e-mail]

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