K3 intermittent low power issue

[K9IR]

My K3 has started intermittently going to lower power--usually around 5W. After some online research, I ran the TX calibration in the K3 utility program, and it failed for both high and low power. So clearly something is amiss. One post said Elecraft support had said to reset the TXGN values back to their defaults. Does anyone know what those default settings are? Any chance this is caused by the oxidation issue? FYI here's the failed results from the TX calibration procedure: K3 Tx Gain Calibration data written on 2012-09-25 at 10:48:22 K3 Serial Number 03093 K3 MCU version 04.51. RS-232 speed 38400 bit/s Elecraft K3 Utility Version 1.12.3.28 01900 kHz TxGain LP 36 03750 kHz TxGain LP 18 05366 kHz TxGain LP 30 07150 kHz TxGain LP 36 10125 kHz TxGain LP 35 14200 kHz TxGain LP 19 18110 kHz TxGain LP 21 21200 kHz TxGain LP 20 01900 kHz TxGain HP 42 03750 kHz TxGain HP 38 05366 kHz TxGain HP 58 07150 kHz TxGain HP 81 10125 kHz TxGain HP 76 14200 kHz TxGain HP 42 18110 kHz TxGain HP 44 21200 kHz TxGain HP 40 Thanks for any help. 73 Paula k9ir

[N8XPQ]

Have you checked the connections of the KPA3 100w amplifier module. I have a friend that was experiencing a similar issue, and discovered that the module had become unseated somewhat causing intermittent RF power output issues. I hope this helps.

best of luck Mike N8XPQ

[K9IR]

Hi Mike--

 

Just saw your reply (in my spam folder!) after returning from a 2 week vacation; thanks very much. I ended up working via email with Elecraft support, but unfortunately we couldn't resolve it, so the rig currently is in CA for repair ;-). I will be very curious to learn from them why the power issue occurred.

 

73 Paula K9IR

From: N8XPQ [via Elecraft] <[hidden email]>
To: K9IR <[hidden email]>
Sent: Thursday, October 4, 2012 4:19 PM
Subject: Re: K3 intermittent low power issue

Have you checked the connections of the KPA3 100w amplifier module. I have a friend that was experiencing a similar issue, and discovered that the module had become unseated somewhat causing intermittent RF power output issues. I hope this helps.

best of luck Mike N8XPQ

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[N4OI - Ken]

K9IR wrote

[...] ended up working via email with Elecraft support, but unfortunately we couldn't resolve it, so the rig currently is in CA for repair ;-). I will be very curious to learn from them why the power issue occurred.
 
73 Paula K9IR

From: N8XPQ -- [...] have you checked the connections of the KPA3 100w amplifier module. I have a friend that was experiencing a similar issue, and discovered that the module had become unseated somewhat causing intermittent RF power output issues. [...]

My K3/100 serial number 6835, which is only about a month old, began having similar intermittent power problems.  For a while it appeared that the "tune" function always worked... but then that also dropped power intermittently.  I just reseated the KPA100 module, the connector board that it plugs into, and that sparsely populated RF board that is used when there is no internal tuner.  So far so good, but too early to tell.  

73 ES GOD BLESS U ES URS DE KEN N4OI

[K9IR]

Ken, thanks for the reply. Preliminary tests indicated I was having the issue with the LPA as well, so reseating the KPA3 wouldn't alone do the trick. My rig came back from Elecraft about a week or so ago. The issue ended up being with the LPA. Something heated up a diode that loosened the soldered connection, creating an intermittent with an associated transistor--which is why at times I would have full power and at other times no power. Usually the transistor fails entirely, so this was a bit more of a challenge--and of interest!--to the Elecraft support crew. But they did resolve it, as well as installing some other upgrades.

 

Nice to have Baby back ;-)!

 

73 Paula k9ir

From: N4OI - Ken [via Elecraft] <[hidden email]>
To: K9IR <[hidden email]>
Sent: Wednesday, November 14, 2012 10:35 AM
Subject: Re: K3 intermittent low power issue

K9IR wrote

[...] ended up working via email with Elecraft support, but unfortunately we couldn't resolve it, so the rig currently is in CA for repair ;-). I will be very curious to learn from them why the power issue occurred.
 
73 Paula K9IR

From: N8XPQ -- [...] have you checked the connections of the KPA3 100w amplifier module. I have a friend that was experiencing a similar issue, and discovered that the module had become unseated somewhat causing intermittent RF power output issues. [...]

My K3/100 serial number 6835, which is only about a month old, began having similar intermittent power problems.  For a while it appeared that the "tune" function always worked... but then that also dropped power intermittently.  I just reseated the KPA100 module, the connector board that it plugs into, and that sparsely populated RF board that is used when there is no internal tuner.  So far so good, but too early to tell.  

73 ES GOD BLESS U ES URS DE KEN N4OI

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[N4OI - Ken]

<quote author="K9IR">
[...] The issue ended up being with the LPA. Something heated up a diode that loosened the soldered connection, creating an intermittent with an associated transistor--which is why at times I would have full power and at other times no power. Usually the transistor fails entirely, so this was a bit more of a challenge--and of interest!--to the Elecraft support crew. [...] 73 Paula k9ir

Thanks for the details, Paula.  My intermittent power problem returned after reseating the boards...  If it occurs at low power, I will check with the Elecraft support folks to see if the likely cause and remedy could be the same as yours.  Thanks again!

73 ES GOD BLESS U ES URS DE KEN N4OI

[K9IR]

Sorry to hear the issues have returned for you, Ken. I know how frustrasting that can be.

 

Rene worked on my rig. He is a really nice guy, provided great explanations and traced out my issues in fairly short order.

 

I'll checlk my paperwork and email you with any other details that might help.

 

73 Paula k9ir

From: N4OI - Ken [via Elecraft] <[hidden email]>
To: K9IR <[hidden email]>
Sent: Wednesday, November 14, 2012 4:01 PM
Subject: Re: K3 intermittent low power issue

<quote author="K9IR">
[...] The issue ended up being with the LPA. Something heated up a diode that loosened the soldered connection, creating an intermittent with an associated transistor--which is why at times I would have full power and at other times no power. Usually the transistor fails entirely, so this was a bit more of a challenge--and of interest!--to the Elecraft support crew. [...] 73 Paula k9ir

Thanks for the details, Paula.  My intermittent power problem returned after reseating the boards...  If it occurs at low power, I will check with the Elecraft support folks to see if the likely cause and remedy could be the same as yours.  Thanks again!

73 ES GOD BLESS U ES URS DE KEN N4OI

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[N4OI - Ken]

<quote author="K9IR">
[...] Rene worked on my rig. He is a really nice guy, provided great explanations and traced out my issues in fairly short order.[...] 73 Paula k9ir

N4OI wrote

[...] My intermittent power problem returned after reseating the boards...  If it occurs at low power, I will check with the Elecraft support folks to see if the likely cause and remedy could be the same as yours. 73 de Ken [...]

Paula, Just to let you know that Rene is not the only wizard at Elecraft support.  Within a few hours of my e-mail, Howard called back, walked me through a few tests, and gave some suggestions.   I tightened the screws on the bottom panel (just like the assembly manual already says to do) and my intermittent power problems seem to have vanished.  I tend to not overtighten to avoid stripping threads, but I squinted hard and used my "screwdriver tight plus a quarter turn" method...  Certainly the folks at Elecraft continue to be "the best Jerry, the best!"  (from Seinfeld...)

73 ES GOD BLESS U ES URS DE KEN N4OI

[K9IR]

Outstanding, Ken. I think Howard also assisted me and one of his suggestions was to verify how tight those screws were. Alas I didn't have your good fortune ;-), and ultimately I needed to send 'er in. But at least I knew Howard had done everything possible to resolve the issues before we were left with that option. Glad to hear you are back in action in short order.

 

The Elecraft support staff--from those who answer the phones and handle the orders to those who provide phone/email assistance and work on the rigs--is simply tremendous.

 

Paula k9ir

From: N4OI - Ken [via Elecraft] <[hidden email]>
To: K9IR <[hidden email]>
Sent: Saturday, November 17, 2012 6:36 AM
Subject: Re: K3 intermittent low power issue

<quote author="K9IR">
[...] Rene worked on my rig. He is a really nice guy, provided great explanations and traced out my issues in fairly short order.[...] 73 Paula k9ir

N4OI wrote

[...] My intermittent power problem returned after reseating the boards...  If it occurs at low power, I will check with the Elecraft support folks to see if the likely cause and remedy could be the same as yours. 73 de Ken [...]

Paula, Just to let you know that Rene is not the only wizard at Elecraft support.  Within a few hours of my e-mail, Howard called back, walked me through a few tests, and gave some suggestions.   I tightened the screws on the bottom panel (just like the assembly manual already says to do) and my intermittent power problems seem to have vanished.  I tend to not overtighten to avoid stripping threads, but I squinted hard and used my "screwdriver tight plus a quarter turn" method...  Certainly the folks at Elecraft continue to be "the best Jerry, the best!"  (from Seinfeld...)

73 ES GOD BLESS U ES URS DE KEN N4OI

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