Re: [Elecraft] FW: KPA500 faults

2022-03-05 Thread Charles K0MV 

Hi William,

"

surmise it was heating

"

Consider as the surface mount current sensing resistor (assuming it is 
surface mount)


is made to withstand solder reflow it seems unlikely to be heat. I've 
had many surface


mount resistors develop hair line cracks due to vibration and board 
flexing (in breadboards I built).


In failures I've seen due to heat, the resistor visibly changes color 
especially in markings, white to


brown.

As long as you have the unit opened up, perhaps you should take a lupe 
or magnifying glass, bright


flashlight and just look around for other cracks in components or solder 
joints.



I hope I can work you on 40M FT8, I need VP2E.


Good luck

Chuck K0MV


On 3/3/22 08:40, Dr. William J. Schmidt wrote:

Sorry guys, this is not a trivial line voltage problem.

The 60V line to the PA does not sag that much (starts at 72V goes to 60V
under FULL LOAD as measured at the PA)... it's in the voltage divider for
the 60V/32 line or the connectors that carry it to the front panel processor
for digitizing.  Changes with heat load.  This amp is in the Caribbean and
there is plenty of excess heat and corrosion. (nb. I just replaced the
current sensing resistor in my K3S for the 100W module due to a hair-line
crack... surmise it was heating).


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ

email:  b...@wjschmidt.com


-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Naumann, Robert, W5OV
Sent: Thursday, March 3, 2022 9:11 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] FW: KPA500 faults


What line voltage are you running it on?  If you're not on 240v, switching
to 240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in
voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the
power supply voltage at the PA module is perfectly fine.  The voltage read
by the processor on the front panel via pin 10 of P1 is lower than it should
be and hence the fault condition.  I suspect there is a voltage divider on
the LPF board that drops the 60 VDC to something that the processor can read
and digitize (in the 0 to 3-5 volt range).  The set of schematics I have do
not show the voltage divider anywhere. does anyone have this part of the
schematics for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

  

  


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ

  

  


email:   <mailto:b...@wjschmidt.com> b...@wjschmidt.com

  

  


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to w...@arrl.org
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to b...@wjschmidt.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to k...@altaeng.com

--
Charles K0MV
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] FW: KPA500 faults

2022-03-03 Thread john 
I believe St Lucia's power is 50Hz if that makes any difference to the
KPA500.

John KK9A

Mike Fatchett w0mu wrote:

St. Lucia is 240v.  I don't know why he would run it on 120v or 110v.

W0MU

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] FW: KPA500 faults

2022-03-03 Thread Mike Fatchett 

St. Lucia is 240v.  I don't know why he would run it on 120v or 110v.

W0MU

On 3/3/2022 1:39 PM, Naumann, Robert, W5OV wrote:

Bill,

Thanks for the additional information.

Can you tell us if you are running it on 120v?

-Bob W5OV


-Original Message-
From: Dr. William J. Schmidt 
Sent: Thursday, March 3, 2022 10:40
To: Naumann, Robert, W5OV ; elecraft@mailman.qth.net
Subject: RE: [Elecraft] FW: KPA500 faults

Sorry guys, this is not a trivial line voltage problem.

The 60V line to the PA does not sag that much (starts at 72V goes to 60V under 
FULL LOAD as measured at the PA)... it's in the voltage divider for the 60V/32 
line or the connectors that carry it to the front panel processor for 
digitizing.  Changes with heat load.  This amp is in the Caribbean and there is 
plenty of excess heat and corrosion. (nb. I just replaced the current sensing 
resistor in my K3S for the 100W module due to a hair-line crack... surmise it 
was heating).


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 
VP2EHZ

email:  b...@wjschmidt.com


-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Naumann, Robert, W5OV
Sent: Thursday, March 3, 2022 9:11 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] FW: KPA500 faults


What line voltage are you running it on?  If you're not on 240v, switching to 
240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in 
voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the power 
supply voltage at the PA module is perfectly fine.  The voltage read by the 
processor on the front panel via pin 10 of P1 is lower than it should be and 
hence the fault condition.  I suspect there is a voltage divider on the LPF 
board that drops the 60 VDC to something that the processor can read and 
digitize (in the 0 to 3-5 volt range).  The set of schematics I have do not 
show the voltage divider anywhere. does anyone have this part of the schematics 
for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

  

  


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 
VP2EHZ

  

  


email:   <mailto:b...@wjschmidt.com> b...@wjschmidt.com

  

  


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to w...@arrl.org 
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to b...@wjschmidt.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to w...@w0mu.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] FW: KPA500 faults

2022-03-03 Thread Naumann, Robert, W5OV 
Bill,

Thanks for the additional information.

Can you tell us if you are running it on 120v?

-Bob W5OV


-Original Message-
From: Dr. William J. Schmidt  
Sent: Thursday, March 3, 2022 10:40
To: Naumann, Robert, W5OV ; elecraft@mailman.qth.net
Subject: RE: [Elecraft] FW: KPA500 faults

Sorry guys, this is not a trivial line voltage problem.

The 60V line to the PA does not sag that much (starts at 72V goes to 60V under 
FULL LOAD as measured at the PA)... it's in the voltage divider for the 60V/32 
line or the connectors that carry it to the front panel processor for 
digitizing.  Changes with heat load.  This amp is in the Caribbean and there is 
plenty of excess heat and corrosion. (nb. I just replaced the current sensing 
resistor in my K3S for the 100W module due to a hair-line crack... surmise it 
was heating).


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 
VP2EHZ

email:  b...@wjschmidt.com


-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Naumann, Robert, W5OV
Sent: Thursday, March 3, 2022 9:11 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] FW: KPA500 faults


What line voltage are you running it on?  If you're not on 240v, switching to 
240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in 
voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the power 
supply voltage at the PA module is perfectly fine.  The voltage read by the 
processor on the front panel via pin 10 of P1 is lower than it should be and 
hence the fault condition.  I suspect there is a voltage divider on the LPF 
board that drops the 60 VDC to something that the processor can read and 
digitize (in the 0 to 3-5 volt range).  The set of schematics I have do not 
show the voltage divider anywhere. does anyone have this part of the schematics 
for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 
VP2EHZ

 

 

email:   <mailto:b...@wjschmidt.com> b...@wjschmidt.com

 

 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to w...@arrl.org 
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to b...@wjschmidt.com 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] FW: KPA500 faults

2022-03-03 Thread Dr. William J. Schmidt 
Sorry guys, this is not a trivial line voltage problem.

The 60V line to the PA does not sag that much (starts at 72V goes to 60V
under FULL LOAD as measured at the PA)... it's in the voltage divider for
the 60V/32 line or the connectors that carry it to the front panel processor
for digitizing.  Changes with heat load.  This amp is in the Caribbean and
there is plenty of excess heat and corrosion. (nb. I just replaced the
current sensing resistor in my K3S for the 100W module due to a hair-line
crack... surmise it was heating).


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ

email:  b...@wjschmidt.com


-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Naumann, Robert, W5OV
Sent: Thursday, March 3, 2022 9:11 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] FW: KPA500 faults


What line voltage are you running it on?  If you're not on 240v, switching
to 240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in
voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the
power supply voltage at the PA module is perfectly fine.  The voltage read
by the processor on the front panel via pin 10 of P1 is lower than it should
be and hence the fault condition.  I suspect there is a voltage divider on
the LPF board that drops the 60 VDC to something that the processor can read
and digitize (in the 0 to 3-5 volt range).  The set of schematics I have do
not show the voltage divider anywhere. does anyone have this part of the
schematics for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
VP2EHZ

 

 

email:   <mailto:b...@wjschmidt.com> b...@wjschmidt.com

 

 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to w...@arrl.org
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to b...@wjschmidt.com 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

[Elecraft] FW: KPA500 faults

2022-03-03 Thread Naumann, Robert, W5OV 


What line voltage are you running it on?  If you're not on 240v, switching to 
240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in 
voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the power 
supply voltage at the PA module is perfectly fine.  The voltage read by the 
processor on the front panel via pin 10 of P1 is lower than it should be and 
hence the fault condition.  I suspect there is a voltage divider on the LPF 
board that drops the 60 VDC to something that the processor can read and 
digitize (in the 0 to 3-5 volt range).  The set of schematics I have do not 
show the voltage divider anywhere. does anyone have this part of the schematics 
for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 
VP2EHZ

 

 

email:    b...@wjschmidt.com

 

 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to w...@arrl.org 
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com