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K3 - no output power

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dl1mgb

K3 - no output power

Hello,

it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg

Following conditions:

- sending into a 50 ohm dummy load
- no matter how many watts are set with PWR knob
- Test mode off
- TX INH off
- all driver transistors working (three screw test)
- no output power also on external watt meter
- happens on all bands
- happens with KPA set to "not inst"
- knocking on housing doesn't change anything
- when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter

I am running out of ideas :-)

73s Chris DL1MGB
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dl1mgb

Re: K3 - no output power

Hi Harald,

spectrum analyzer and more space on the table would be the best, but both not available :-)

Additional information:
- internal voltage / current (DISP)

Standby: 13.8 V / 0.86 A
Tune: 13.4 V / 3.20 A

And still no power output on the external wattmeter.

It seems that there is something produced, but it doesn't exit the K3.

I also did an EE INIT, ut no change.

73s Chris

Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):

> Hello Chris,
>
>
>
> strange is, that your Display does not show a frequency, but it should.
>
>
>
> I had a water Intrusion in 2019 which causes several defects.
>
> I was testing along the Signal path to see the Signal (with RSP-spectrum analyzer), that helped me, to find the defects. It tooks a while also with help of the list here.
>
>
>
> Receiving is working?
>
>
>
> Vy73 & GL
>
> Harald
>
> DD0VS
>
>
>
>
>
>
>
> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10
>
>
>
> *Von: *Christian Janssen DL1MGB <mailto:[hidden email]>
> *Gesendet: *Mittwoch, 24. März 2021 21:05
> *An: *[hidden email] <mailto:[hidden email]>
> *Betreff: *[Elecraft] K3 - no output power
>
>
>
> Hello,
>
>
>
> it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg
>
>
>
> Following conditions:
>
>
>
> - sending into a 50 ohm dummy load
>
> - no matter how many watts are set with PWR knob
>
> - Test mode off
>
> - TX INH off
>
> - all driver transistors working (three screw test)
>
> - no output power also on external watt meter
>
> - happens on all bands
>
> - happens with KPA set to "not inst"
>
> - knocking on housing doesn't change anything
>
> - when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter
>
>
>
> I am running out of ideas :-)
>
>
>
> 73s Chris DL1MGB
>
> ______________________________________________________________
>
> Elecraft mailing list
>
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/mmfaq.htm
>
> Post: mailto:[hidden email]
>
>
>
> This list hosted by: http://www.qsl.net
>
> Please help support this email list: http://www.qsl.net/donate.html
>
> Message delivered to [hidden email]
>
>
>

Wes Stewart-2

Re: K3 - no output power

In reply to this post by dl1mgb

Does it receive?

Wes N7WS

On 3/24/2021 1:03 PM, Christian Janssen DL1MGB wrote:

wa6vab

Re: K3 - no output power

In reply to this post by dl1mgb

Harald
I think you need to start at Ground Zero,,,,,,
Go to your Elecraft Utility
And connect to the K3 Radio and verify
The Firmware is present (05.67 ect)
I would go to the Basic mode of operations.
Set K3 to SSB operation Upper or Lower , Freq middle of band.
Set radio to PTT (not VOX) Ant 1, load to Ant 1.
Verify on K3 DVM , voltage is 13 volts.
Push Tune button (long for TX – with RF)
Adjust PWR knob Clockwise for Max RF power.
Take readings………. Ray WA6VAB K3

From: Christian Janssen DL1MGB
Sent: Wednesday, March 24, 2021 1:49 PM
To: Harald Fritzsche (DD0VS); [hidden email]
Subject: Re: [Elecraft] K3 - no output power

Hi Harald,

spectrum analyzer and more space on the table would be the best, but both not available :-)

Additional information:
- internal voltage / current (DISP)

Standby: 13.8 V / 0.86 A
Tune: 13.4 V / 3.20 A

And still no power output on the external wattmeter.

It seems that there is something produced, but it doesn't exit the K3.

I also did an EE INIT, ut no change.

73s Chris

Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):

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dl1mgb

Re: K3 - no output power

Update:

- reseted all TMP connectors
- already changed the pin headers at the KPA3 (had the 12V ERR some months ago), since then radio was good for some hundred QSOs
- no transverter available
- serial number is 1532
- K3 receives without any problems
- uploaded the newest firmware

No change.

I don't have a spectrum analyzer, but I will look with my eyes if there is something noticeable.

73s Chris DL1MGB

Am 25.03.2021 um 02:35 schrieb Ray:

>
>
>
>
> Harald
>
> I think you need to start at Ground Zero,,,,,,
>
> Go to your Elecraft Utility
>
> And connect to the K3 Radio and verify
>
> The Firmware is present (05.67 ect)
>
> I would go to the Basic mode of operations.
>
> Set K3 to SSB operation Upper or Lower , Freq middle of band.
>
> Set radio to PTT (not VOX) Ant 1, load to Ant 1.
>
> Verify on K3 DVM , voltage is 13 volts.
>
> Push Tune button (long for TX – with RF)
>
> Adjust PWR knob Clockwise for Max RF power.
>
> Take readings………. Ray WA6VAB K3
>
>
>
> *From: *Christian Janssen DL1MGB <mailto:[hidden email]>
> *Sent: *Wednesday, March 24, 2021 1:49 PM
> *To: *Harald Fritzsche (DD0VS) <mailto:[hidden email]>; [hidden email] <mailto:[hidden email]>
> *Subject: *Re: [Elecraft] K3 - no output power
>
>
>
> Hi Harald,
>
>
>
> spectrum analyzer and more space on the table would be the best, but both not available :-)
>
>
>
> Additional information:
>
> - internal voltage / current (DISP)
>
>
>
> Standby: 13.8 V / 0.86 A
>
> Tune: 13.4 V / 3.20 A
>
>
>
> And still no power output on the external wattmeter.
>
>
>
> It seems that there is something produced, but it doesn't exit the K3.
>
>
>
> I also did an EE INIT, ut no change.
>
>
>
> 73s Chris
>
>
>
>
>
>
>
> Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):
>
>> Hello Chris,
>
>>
>
>>
>
>>
>
>> strange is, that your Display does not show a frequency, but it should.
>
>>
>
>>
>
>>
>
>> I had a water Intrusion in 2019 which causes several defects.
>
>>
>
>> I was testing along the Signal path to see the Signal (with RSP-spectrum analyzer), that helped me, to find the defects. It tooks a while also with help of the list here.
>
>>
>
>>
>
>>
>
>> Receiving is working?
>
>>
>
>>
>
>>
>
>> Vy73 & GL
>
>>
>
>> Harald
>
>>
>
>> DD0VS
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10
>
>>
>
>>
>
>>
>
>> *Von: *Christian Janssen DL1MGB <mailto:[hidden email]>
>
>> *Gesendet: *Mittwoch, 24. März 2021 21:05
>
>> *An: *[hidden email] <mailto:[hidden email]>
>
>> *Betreff: *[Elecraft] K3 - no output power
>
>>
>
>>
>
>>
>
>> Hello,
>
>>
>
>>
>
>>
>
>> it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg
>
>>
>
>>
>
>>
>
>> Following conditions:
>
>>
>
>>
>
>>
>
>> - sending into a 50 ohm dummy load
>
>>
>
>> - no matter how many watts are set with PWR knob
>
>>
>
>> - Test mode off
>
>>
>
>> - TX INH off
>
>>
>
>> - all driver transistors working (three screw test)
>
>>
>
>> - no output power also on external watt meter
>
>>
>
>> - happens on all bands
>
>>
>
>> - happens with KPA set to "not inst"
>
>>
>
>> - knocking on housing doesn't change anything
>
>>
>
>> - when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter
>
>>
>
>>
>
>>
>
>> I am running out of ideas :-)
>
>>
>
>>
>
>>
>
>> 73s Chris DL1MGB
>
>>
>
>> ______________________________________________________________
>
>>
>
>> Elecraft mailing list
>
>>
>
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>
>>
>
>> Help: http://mailman.qth.net/mmfaq.htm
>
>>
>
>> Post: mailto:[hidden email]
>
>>
>
>>
>
>>
>
>> This list hosted by: http://www.qsl.net
>
>>
>
>> Please help support this email list: http://www.qsl.net/donate.html
>
>>
>
>> Message delivered to [hidden email]
>
>>
>
>>
>
>>
>
> ______________________________________________________________
>
> Elecraft mailing list
>
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/mmfaq.htm
>
> Post: mailto:[hidden email]
>
>
>
> This list hosted by: http://www.qsl.net
>
> Please help support this email list: http://www.qsl.net/donate.html
>
> Message delivered to [hidden email]
>
>
>

dl1mgb

Re: K3 - no output power

In reply to this post by dl1mgb

I am not sure if there is a frequency shown when in TUNE mode. My memories tell me that the top line shows the SWR and the bottom line shows the power.

73s Chris

Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):

dd0vs

Re: K3 - no output power

Hello Chris, all,

According to your current consumption the 10w PA driver is working, but KPA3 gets no input or has not 12V.
Check CB1 CKT BKR (KPA3 page 1 of 2 in K3 schematics) and check if TR-Switch gets plausible voltages (KPA3 page 2 of 2, 7R and 7T).

Since there is no plausible idle current from KPA3 the CB1 seems to be defect, most likely.
Not sure if this can happen.
Or give me a call, # sent separetly.
Vy73
Harald
DD0VS

.-.-. --... ...-- -.. -.. ----- ...- ...

> Am 25.03.2021 um 05:35 schrieb Christian Janssen DL1MGB <[hidden email]>:
>
> I am not sure if there is a frequency shown when in TUNE mode. My memories tell me that the top line shows the SWR and the bottom line shows the power.
>
> 73s Chris
>
>
>
>> Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):
>> Hello Chris,
>>
>>
>>
>> strange is, that your Display does not show a frequency, but it should.
>>
>>
>>
>> I had a water Intrusion in 2019 which causes several defects.
>>
>> I was testing along the Signal path to see the Signal (with RSP-spectrum analyzer), that helped me, to find the defects. It tooks a while also with help of the list here.
>>
>>
>>
>> Receiving is working?
>>
>>
>>
>> Vy73 & GL
>>
>> Harald
>>
>> DD0VS
>>
>>
>>
>>
>>
>>
>>
>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10
>>
>>
>>
>> *Von: *Christian Janssen DL1MGB <mailto:[hidden email]>
>> *Gesendet: *Mittwoch, 24. März 2021 21:05
>> *An: *[hidden email] <mailto:[hidden email]>
>> *Betreff: *[Elecraft] K3 - no output power
>>
>>
>>
>> Hello,
>>
>>
>>
>> it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg
>>
>>
>>
>> Following conditions:
>>
>>
>>
>> - sending into a 50 ohm dummy load
>>
>> - no matter how many watts are set with PWR knob
>>
>> - Test mode off
>>
>> - TX INH off
>>
>> - all driver transistors working (three screw test)
>>
>> - no output power also on external watt meter
>>
>> - happens on all bands
>>
>> - happens with KPA set to "not inst"
>>
>> - knocking on housing doesn't change anything
>>
>> - when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter
>>
>>
>>
>> I am running out of ideas :-)
>>
>>
>>
>> 73s Chris DL1MGB
>>
>> ______________________________________________________________
>>
>> Elecraft mailing list
>>
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>
>> Help: http://mailman.qth.net/mmfaq.htm
>>
>> Post: mailto:[hidden email]
>>
>>
>>
>> This list hosted by: http://www.qsl.net
>>
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>> Message delivered to [hidden email]
>>
>>
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

dl1mgb

Re: K3 - no output power

CB1 is OK, voltage is available after the breaker.

7R standby: 6 V / TUNE: 0,2 V
7T standby: 0 V / TUNE: 6 V

73s Chris

Am 25.03.2021 um 06:45 schrieb Harald Fritzsche:

> Hello Chris, all,
>
> According to your current consumption the 10w PA driver is working, but KPA3 gets no input or has not 12V.
> Check CB1 CKT BKR (KPA3 page 1 of 2 in K3 schematics) and check if TR-Switch gets plausible voltages (KPA3 page 2 of 2, 7R and 7T).
>
> Since there is no plausible idle current from KPA3 the CB1 seems to be defect, most likely.
> Not sure if this can happen.
> Or give me a call, # sent separetly.
> Vy73
> Harald
> DD0VS
>
> .-.-. --... ...-- -.. -.. ----- ...- ...
>
>> Am 25.03.2021 um 05:35 schrieb Christian Janssen DL1MGB <[hidden email]>:
>>
>> I am not sure if there is a frequency shown when in TUNE mode. My memories tell me that the top line shows the SWR and the bottom line shows the power.
>>
>> 73s Chris
>>
>>
>>
>>> Am 24.03.2021 um 21:32 schrieb Harald Fritzsche (DD0VS):
>>> Hello Chris,
>>>
>>>
>>>
>>> strange is, that your Display does not show a frequency, but it should.
>>>
>>>
>>>
>>> I had a water Intrusion in 2019 which causes several defects.
>>>
>>> I was testing along the Signal path to see the Signal (with RSP-spectrum analyzer), that helped me, to find the defects. It tooks a while also with help of the list here.
>>>
>>>
>>>
>>> Receiving is working?
>>>
>>>
>>>
>>> Vy73 & GL
>>>
>>> Harald
>>>
>>> DD0VS
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10
>>>
>>>
>>>
>>> *Von: *Christian Janssen DL1MGB <mailto:[hidden email]>
>>> *Gesendet: *Mittwoch, 24. März 2021 21:05
>>> *An: *[hidden email] <mailto:[hidden email]>
>>> *Betreff: *[Elecraft] K3 - no output power
>>>
>>>
>>>
>>> Hello,
>>>
>>>
>>>
>>> it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg
>>>
>>>
>>>
>>> Following conditions:
>>>
>>>
>>>
>>> - sending into a 50 ohm dummy load
>>>
>>> - no matter how many watts are set with PWR knob
>>>
>>> - Test mode off
>>>
>>> - TX INH off
>>>
>>> - all driver transistors working (three screw test)
>>>
>>> - no output power also on external watt meter
>>>
>>> - happens on all bands
>>>
>>> - happens with KPA set to "not inst"
>>>
>>> - knocking on housing doesn't change anything
>>>
>>> - when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter
>>>
>>>
>>>
>>> I am running out of ideas :-)
>>>
>>>
>>>
>>> 73s Chris DL1MGB
>>>
>>> ______________________________________________________________
>>>
>>> Elecraft mailing list
>>>
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>
>>> Help: http://mailman.qth.net/mmfaq.htm
>>>
>>> Post: mailto:[hidden email]
>>>
>>>
>>>
>>> This list hosted by: http://www.qsl.net
>>>
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>> Message delivered to [hidden email]
>>>
>>>
>>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>

Jim Brown-10

Re: K3 - no output power

In reply to this post by dl1mgb

On 3/24/2021 9:28 PM, Christian Janssen DL1MGB wrote:
> I don't have a spectrum analyzer, but I will look with my eyes if there is something noticeable.

A frequency counter can also be a useful RF probe for your own TX

73, Jim K9YC
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dl1mgb

Re: K3 - no output power

In reply to this post by dl1mgb

Hello,

together with Harald DD0VS, we narrowed it down to the diode D1 on the LPA board. I will now order the diode and some probably affected parts around the diode and start replacing and testing again.

I will report again.

Many thanks to all others with giving different hints!

73s Chris DL1MGB

Am 24.03.2021 um 21:03 schrieb Christian Janssen DL1MGB:

> Hello,
>
> it happened during the Russian DX Contest last Saturday, from one second to another. No output. When I tune the display looks like this: http://dl1mgb.com/temp/k3_no_power.jpg
>
> Following conditions:
>
> - sending into a 50 ohm dummy load
> - no matter how many watts are set with PWR knob
> - Test mode off
> - TX INH off
> - all driver transistors working (three screw test)
> - no output power also on external watt meter
> - happens on all bands
> - happens with KPA set to "not inst"
> - knocking on housing doesn't change anything
> - when starting the antenna tuner, it says 5.0 watts, but no output on the external watt meter
>
> I am running out of ideas :-)
>
> 73s Chris DL1MGB
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

KeithWE6R

Re: K3 - no output power

Administrator

Chris;
Since you EE INIT-ed your radio, you MUST re-load a known-good saved
configuration!
Or setup all options, filters etc and do the transmit gain calibrations.
An EE INIT reset blanks the radio and sets it to ONE filter, (a 2.7,
with no offset, in slot 1).
Keith WE6R Elecraft K3/K4 Tech

______________________________________________________________
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dl1mgb

Re: K3 - no output power

In reply to this post by dl1mgb

Hi all,

just wanted to let you know that my K3 is back again with full output power.

We found the Diode D1 on the LPA board. On the anode side, it had shown full power, on the other side, nothing. When unsoldering it, it was already very loose. The diode itself was intact, but had no contact at all. Most probably it got loose after heating up and unsoldering itself. New diode soldered in, TUNE, smoke. After comparing some voltages around the diode, we found Q6 to be faulty. That's why more than the maximum rated current of 1A flowed through the diode. Changed also the transistor and now everything was working again, full power, no smoke, no smell.

Most probably, it has to do with the same problem as DK3WE already experienced 8 years ago: http://www.the-mule.de/?p=1275#more-1275

Many thanks again for DD0VS for helping me in finding the faulty parts!

73s Chris DL1MGB

Am 24.03.2021 um 21:03 schrieb Christian Janssen DL1MGB:

KeithWE6R

Re: K3 - no output power

Administrator

Just some notes for future folks reading this.
I always replace D1 and Q6 together.
Other notes re Q6 and D1;
1. Poor RX on 24 and 28Mhz 12m 10M only and TX gain is OK. Q6 a 2N7002,
OR D1 on the LPA can Suck the RX down on these two bands!!
2. Slow ramp up of TX power output. Typically worse on higher frequencies.
This can be D1 E560040 burnt (or bad solder joint) and/or bad Q6 E580026
on LPA. (power ramps up starting very low).
3. If Q6 shorts, it can take out Q3 E580030. **REPLACE D1 *and* Q6 if
the solder joint is bad!!!
Keith WE6R Elecraft K3/K4 Tech
______________________________________________________________
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