[Elecraft] K3 transmitter power woes

[Don Wilhelm]

Chet,

It sounds like you do not have sufficient audio drive.

In DATA A mode, how many ALC bars do you obtain?  You must have 4 bars 
solid with the 5th one flashing.
Adjust the audio levels from the computer to achieve that - I assume you 
are using LINE in.

73,
Don W3FPR

On 9/13/2021 3:56 PM, chetsubaccount at snet.net wrote:
> My K3 transmitter has been struggling for months to behave. I've heard the
> service dept turnaround in CA is very long so I might not see it the rest of
> the year if I sent it in and wanted to avoid that if possible. I've followed
> advice suggested here with no lasting success.
>
> Especially on 6M the power sometimes takes a long time deciding to reach the
> setpoint. Sometimes it will be OK, but a few hours later after just sitting
> there, it again won't, and drops to a low output level.
>
> I've run the transmitter gain calibration routine again and again and it
> fails. Sometimes I get an ERRTXG on 160, 80, 40M. Sometimes the 5W
> calibration shows errtxg as it runs but the utility says the calibration had
> succeeded.
>
> I've checked that the bandpass filters are OK by using an antenna analyzer
> with an attenuator to check receiver sensitivity- all bands seem pretty
> close.
>
> I've rechecked if the LPA FET's are ok (I changed two last year), and set
> their bias current levels again and all seems well with them.
>
> I've upped the supply voltage- that seems to work for a day or two but then
> same old problems come back
>
> I've replaced the fwd and rev power meter Schottky diodes, no fix.
>
> Sometimes when the transmitter fails to reach the set power level, I can
> tweak the pwr knob and it will reach the changed level, but sometimes not
> and it falls back to a lower value. On 6M, while in "tune" if the power does
> not reach the setpoint (e.g. 30W) and I turn the pwr knob down below 12
> where the 100w amp is bypassed and then turn it back up to reengage the 100w
> amp, the power will sometimes reach and stay at the setpoint (30W). But that
> condition does not stay Ok too long.
>
> The transverter output also exhibits similar power problems
>
> I've reloaded the firmware. The utility initially reported  "checksum
> reconciliation value" and I have no idea what that means.
>
> And finally, this weekend, when I set the  receive mode to data-a, the audio
> output had shifted to a higher freq spectrum width (e.g. 500-3300) on the
> WSJT spectrum display with clearly more hiss in the speaker. Cycling the
> xtal filters, normalling the shifts and widths had no effect. Changed the
> mode to USB and the audio spectrum was normal, change back to data-a and it
> was shifted. So I operated WSJT-X in USB. Hours later, data-a was back to
> normal. First time I've observed that. Today it is AOK. GOK what happened
> Saturday.
>
> Any other suggestions before I bit the bullet and prepare to send it to
> Elecraft? Thanks for any ideas.
>
> Chet, N8RA
>
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