K3-S has no power output


Dick McClain
 

Can you help me with a broken K3-S? It has no TX power output at all. Otherwise, normal function all OK.

 

Suspect the MOSFETs in Low Power Amplifier have failed. I tried using the Elecraft Utility TX Gain Calibration and it failed all levels (50 watt, 5 watt and Milliwatt) with message that test measured no transmitter power output.

 

Failure occurred when I was trying to work some of the military stations during Armed Forces Day. I did work two of them, both on CW mode. Since those stations are out of normal Ham frequencies, I was doing a lot of button pushing to key in frequencies, mode, VFO selection and such. At some point, I saw a flash of light on front panel of the KPA500 amp that I didn’t expect. Perhaps I keyed the TX on VFO that was out of band and had high SWR. Although the K3 is protected and prevents out of band operation, I may have damaged it.

 

I have tried all the following:

  • DC voltage is 13.7 on K3 front panel display and DC power supply using DMM
  • Transmitter is not in TEST mode, the K3 display TX symbol is not blinking
  • ANT 1 is selected and dummy load is on ANT1 connector
  • VOX is selected for CW mode
  • As mentioned above, Elecraft Utility test failed TX Calibration
  • CONFIG:TX INH is OFF
  • When keying CW, Red TX LED is blinking and I hear sidetone
  • I have no Sub Receiver
  • Receiving is normal on all bands and modes

 

Transceiver has been working well until yesterday.

 

Do you have other suggestions to debug and verify this problem?

 

Thank you and 73,

Dick, KD4S

 


Ray Maxfield
 

Hi Dick..

Make sure your back in the Normal Ham Bands !

Disconnect the K3S from the Amp and connect it to a Real 50 Ohm Load.

Re-run the Elecraft Utility TX Gain Calibration again.

 

Another test is…. Move your Mode to CW,

Move the VFO B knob to read Current….

My normal Rec  is about 0.88 A

When   I Press the XMIT Button down (long) the Current show’s 2.85 A 

And the RF show’s 5 Watts…..  

 

WA6VAB K3  Ray

 

 

Sent from Mail for Windows

 

From: Dick McClain
Sent: Monday, May 16, 2022 1:57 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3-S has no power output

 

Can you help me with a broken K3-S? It has no TX power output at all. Otherwise, normal function all OK.

 

Suspect the MOSFETs in Low Power Amplifier have failed. I tried using the Elecraft Utility TX Gain Calibration and it failed all levels (50 watt, 5 watt and Milliwatt) with message that test measured no transmitter power output.

 

Failure occurred when I was trying to work some of the military stations during Armed Forces Day. I did work two of them, both on CW mode. Since those stations are out of normal Ham frequencies, I was doing a lot of button pushing to key in frequencies, mode, VFO selection and such. At some point, I saw a flash of light on front panel of the KPA500 amp that I didn’t expect. Perhaps I keyed the TX on VFO that was out of band and had high SWR. Although the K3 is protected and prevents out of band operation, I may have damaged it.

 

I have tried all the following:

  • DC voltage is 13.7 on K3 front panel display and DC power supply using DMM
  • Transmitter is not in TEST mode, the K3 display TX symbol is not blinking
  • ANT 1 is selected and dummy load is on ANT1 connector
  • VOX is selected for CW mode
  • As mentioned above, Elecraft Utility test failed TX Calibration
  • CONFIG:TX INH is OFF
  • When keying CW, Red TX LED is blinking and I hear sidetone
  • I have no Sub Receiver
  • Receiving is normal on all bands and modes

 

Transceiver has been working well until yesterday.

 

Do you have other suggestions to debug and verify this problem?

 

Thank you and 73,

Dick, KD4S

 

 


Carter, Michael
 

Dick,

In addition to Ray's suggestions, I would check for
RF in TX mode on the PIN diode T/R switch on the RF Board.
While it's possible that a PA transistor failed in the LPA
(10 watt) module, the fact that you get no RF output at
any power level (including the 1 mW level), yet the
receiver functions normally, suggests a failure in the
T/R switch on one of the diode paths routing TX signal
to the LPA and PA modules.

73,
Mike, K8CN


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Ray Maxfield <wa6vab@...>
Sent: Monday, May 16, 2022 5:38 PM
To: Elecraft-K3@groups.io <Elecraft-K3@groups.io>
Subject: Re: [Elecraft-K3] K3-S has no power output
 

CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Hi Dick..

Make sure your back in the Normal Ham Bands !

Disconnect the K3S from the Amp and connect it to a Real 50 Ohm Load.

Re-run the Elecraft Utility TX Gain Calibration again.

 

Another test is…. Move your Mode to CW,

Move the VFO B knob to read Current….

My normal Rec  is about 0.88 A

When   I Press the XMIT Button down (long) the Current show’s 2.85 A 

And the RF show’s 5 Watts…..  

 

WA6VAB K3  Ray

 

 

Sent from Mail for Windows

 

From: Dick McClain
Sent: Monday, May 16, 2022 1:57 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3-S has no power output

 

Can you help me with a broken K3-S? It has no TX power output at all. Otherwise, normal function all OK.

 

Suspect the MOSFETs in Low Power Amplifier have failed. I tried using the Elecraft Utility TX Gain Calibration and it failed all levels (50 watt, 5 watt and Milliwatt) with message that test measured no transmitter power output.

 

Failure occurred when I was trying to work some of the military stations during Armed Forces Day. I did work two of them, both on CW mode. Since those stations are out of normal Ham frequencies, I was doing a lot of button pushing to key in frequencies, mode, VFO selection and such. At some point, I saw a flash of light on front panel of the KPA500 amp that I didn’t expect. Perhaps I keyed the TX on VFO that was out of band and had high SWR. Although the K3 is protected and prevents out of band operation, I may have damaged it.

 

I have tried all the following:

  • DC voltage is 13.7 on K3 front panel display and DC power supply using DMM
  • Transmitter is not in TEST mode, the K3 display TX symbol is not blinking
  • ANT 1 is selected and dummy load is on ANT1 connector
  • VOX is selected for CW mode
  • As mentioned above, Elecraft Utility test failed TX Calibration
  • CONFIG:TX INH is OFF
  • When keying CW, Red TX LED is blinking and I hear sidetone
  • I have no Sub Receiver
  • Receiving is normal on all bands and modes

 

Transceiver has been working well until yesterday.

 

Do you have other suggestions to debug and verify this problem?

 

Thank you and 73,

Dick, KD4S

 

 


Dick McClain
 

Thanks for reply, Ray,
The above tests were done in normal ham bands, KPA500 disconnected and 50-ohm dummy connected to K3-S ANT1.

Current = 1.36 A in CW receive mode.
Current = 2.18 A in CW transmit mode while K3 PWR set for 10 watts. P3 display with TX monitor shows 1 watts and noisy waveform

Current = 3.0 A in CW transmit mode while K3 PWR set for 20 watts (HPA engaged). P3 display shows 0.18 watt and noisy waveform


Dick McClain
 

Mike, Thank you for reply.

Good suggestion but I don't know how to check for RF on PIN diode. 


Ray Maxfield
 

Go to the K3s Configure App (cant remember the exact name)

And do a Reload of the Configure File.

It is where you set what filter for each mode. 

I need COFFEE !   ray   

 

From: Dick McClain
Sent: Tuesday, May 17, 2022 5:09 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] K3-S has no power output

 

Thanks for reply, Ray,
The above tests were done in normal ham bands, KPA500 disconnected and 50-ohm dummy connected to K3-S ANT1.

Current = 1.36 A in CW receive mode.
Current = 2.18 A in CW transmit mode while K3 PWR set for 10 watts. P3 display with TX monitor shows 1 watts and noisy waveform

Current = 3.0 A in CW transmit mode while K3 PWR set for 20 watts (HPA engaged). P3 display shows 0.18 watt and noisy waveform

 


WE6R
 

If there is no MW output, then it is -not- the LPA or KPA.
More likely the KSYN3A has died or something up front in the radio, KREF3 cable etc.
However, if the RX is good, the KSYN3A is OK.
(Do NOT reset the radio unless you are prepared to load a known good backup). 
The very bottom coax going from the KREF3 to the RF board is the TX IF out, if that is flaky, it will RX and not TX.

Are you sure there is no MW output?;
Try putting the KXV3 in TEST and set power for 1.0MW exactly, then do a long-press XMIT to do a TUNE,,
What happens? (Don't forget to put it back to "nor" when done, ask me why, hi hi)
This will do a manual TX gain, you should have a dummy load on the XVTR OUT BNC, but not critical for testing, just don't do it on 6meters.
Keith WE6R Elecraft K3/K4 Tech


Dick McClain
 

Keith, thank you for reply. On Sunday, I sent a message using Elecraft Customer Support to describe my issue. 
Have no reply yet. Does that go to you?

With 50-ohm dummy on XVTR OUT and KXV3 in TEST, I did a long press of TUNE button while in CW mode.
I see "1.00 MW" in VFO B display and "0.0 db" in VFO A display.

Is that good? What is next step? Order a K4?

73,
Dick, KD4S

PS: I put it back in NOR mode.   8-)


Ray Maxfield
 

 

 

Ok, another Test…. 3 Finger Test.

 

On the Bottom of the Radio you will find 3 Screws that have small Lock Washers  Under the Heads.

 Location:   About Half way back , middle of the radio, at the Split point of the bottom covers.

You will need to place your 3 Fingers on the Screw Head to see if the get warm /Hot……..

 

In the SSB Mode,  Key your PTT

If any of the 3 get Hot, they are Most likely Shorted.

WA6VAB Ray  K3

 

From: Dick McClain
Sent: Tuesday, May 17, 2022 5:09 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] K3-S has no power output

 

Thanks for reply, Ray,
The above tests were done in normal ham bands, KPA500 disconnected and 50-ohm dummy connected to K3-S ANT1.

Current = 1.36 A in CW receive mode.
Current = 2.18 A in CW transmit mode while K3 PWR set for 10 watts. P3 display with TX monitor shows 1 watts and noisy waveform

Current = 3.0 A in CW transmit mode while K3 PWR set for 20 watts (HPA engaged). P3 display shows 0.18 watt and noisy waveform

 


Ray Maxfield
 

 

 

Dick…. I think that’s a Good Sign. ( 1.00 MW )

You might have a Long wile before you can get back on the Air,

Delivery time looks Long on the K4.

 

WA6VAB  Ray K3

 

From: Dick McClain
Sent: Tuesday, May 17, 2022 11:49 AM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] K3-S has no power output

 

Keith, thank you for reply. On Sunday, I sent a message using Elecraft Customer Support to describe my issue. 
Have no reply yet. Does that go to you?

With 50-ohm dummy on XVTR OUT and KXV3 in TEST, I did a long press of TUNE button while in CW mode.
I see "1.00 MW" in VFO B display and "0.0 db" in VFO A display.

Is that good? What is next step? Order a K4?

73,
Dick, KD4S

PS: I put it back in NOR mode.   8-)

 


Dick McClain
 

Ray, I held fingers on the 3 screws for about one minute while TUNE was depressed. None got hot.

You said SSB mode, and I selected that mode. But when I do a long press of the XMIT (to enable TUNE) the mode switched to CW.

Did I misunderstand?


WE6R
 

That indicates it *is* making MW power, so unknown why it failed that calibration.
So, looks like you have a LPA issue.
If all 3 are cold, probably something besides them.
Set radio to SSB, take bottom cover off, do the 3-finger test again but this time only -TAP- the XMIT to turn on bias and NOT go into full transmit.
If Q2 (driver) gets warm and (finals) Q4&5 don't, it is probably those. 
If none get hot, start checking voltages. I just got your forward from CS. I can send schematics,
Or you can get an RSA # to send in, there is a wait list but I am working thru them faster now.
Keith WE6R


Carter, Michael
 

Dick,
Do you have access to a scope or voltmeter with
a simple RF probe?

The fact that you have milliwatt output at the
XVTR OUT jack is a good sign.  Still not conclusive
about whether the fault is in the T/R switch
(PIN diodes) or the 10 watt low power PA
module or the PIN diode switch that bypasses
the 100 watt PA.

Mike, K8CN


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Dick McClain <dickmcclain@...>
Sent: Tuesday, May 17, 2022 2:49 PM
To: Elecraft-K3@groups.io <Elecraft-K3@groups.io>
Subject: Re: [Elecraft-K3] K3-S has no power output
 

CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Keith, thank you for reply. On Sunday, I sent a message using Elecraft Customer Support to describe my issue. 
Have no reply yet. Does that go to you?

With 50-ohm dummy on XVTR OUT and KXV3 in TEST, I did a long press of TUNE button while in CW mode.
I see "1.00 MW" in VFO B display and "0.0 db" in VFO A display.

Is that good? What is next step? Order a K4?

73,
Dick, KD4S

PS: I put it back in NOR mode.   8-)


Wes Stewart
 

Why not do the bias test in message 33816?

https://groups.io/g/Elecraft-K3/message/33816

Wes  N7WS


Ray Maxfield
 

Dick… you did fine……

Test:  In the SSB Mode……

Press the XMIT button.

Turn the PWR control CCW ( lower)

The RF display will Show Something….

When the power goes below about 8 Watt, you should HEAR the Relay Click,

If you Move PWR back and Forth it should CLICK both ways UP and Down… ?

 

Ray WA6VAB  K3

 

 

From: Dick McClain
Sent: Tuesday, May 17, 2022 12:30 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] K3-S has no power output

 

Ray, I held fingers on the 3 screws for about one minute while TUNE was depressed. None got hot.

You said SSB mode, and I selected that mode. But when I do a long press of the XMIT (to enable TUNE) the mode switched to CW.

Did I misunderstand?

 


Ron Wilcox
 

Dick I am having the same issue. I received an email from Doug at Elecraft with instructions and tests to perform. I will forward it to you when I am back at my computer and then you can fill it out and send it in. Some of the instructions are different than what you are being told so you might want to wait before you do anything else and use their information --

Hope you have a nice day!

Ron Wilcox KF7ZN
RN, BSH, BSN
ARRL & W5YI Volunteer Examiner
Davis County Assistant Emergency Coordinator (ARES)