Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Jim Brown]

On 4/25/2022 4:15 AM, Andy Durbin wrote:

My test data showed no significant advantage in temperature control over just 
letting KPA 500 decide when to run the fan.


Neighbor K6XX, a serious contester and the Elecraft engineer responsible 
for putting both of their amps into production, advised me to use the 
default settings for fan control, letting the firmware deal with thermal 
issues. Bob knows that I do a LOT with WSJT modes on 6M during the 
summer. He also advised me to turn off the amp when not in use, noting 
that fans have the lowest MTBF of any parts in the amps, thanks in part 
to the accumulation of dust.


73, Jim K9YC
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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Andy Durbin]

"Is there data showing more dissipated heat with lower output in solid state 
amplifiers? "

I have test data for my KPA500 and it's very obvious that this amplifier has 
higher PA heat dissipation at half power than at full power.  Not just less 
efficient as a percentage of power output but the absolute dissipation is 
higher.

At low power the absolute dissipation is lower than at full power but the 
efficiency is still lower.  The worse place to run a KPA500 is in the 200-300 W 
output region.  Note also that KPA500 PA dissipation is very dependent on load 
matching.

I've posted this before but some of my test data can be seen here - 
https://tinyurl.com/2kdrjmt3

73,
Andy, k3wyc



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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Andy Durbin]

Sorry  - too early in the morning - "KPA500" not "KPA 500".

Andy, k3wyc


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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Andy Durbin]

"Now, my question for everyone reading - when is it that you feel the need to 
set the fan speed above 0?"

I coded my station controller to provide an option to start KPA 500 fan at 
start of TX and have it run for a fixed time after TX stops.  My test data 
showed no significant advantage in temperature control over just letting KPA 
500 decide when to run the fan.

My KPA 500 is better instrumented than most.  I record KPA 500 finals 
temperature, temperature at the "Z" bracket, temperature at a heat sink fin, 
and fan speed, all at 1 Hz so I think I have a good data set.

I left the option in the code but do not enable it.  My minimum fan speed is 
zero.

73,
Andy, k3wyc
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[Elecraft] K4D - KPA500 Fault Question + wish

[Bob McGraw]

Based on my experience with my KPA500 and an exchange with Jack, W6FB, I 
have found no need to run the Fan Speed at any value other than NOR as 
defined via the MENU.   {See my comments regarding efficiency.}


I'm aware that "others" have measured and tracked and computed results 
to an extensive numerical value.  OK so be it.  It is your amp.  I just 
choose to run mine in the "quiet" mode of NORMAL {and not suck in a load 
of dust by it running all the time} and allow the control system in the 
amp to apply the fan and fan speed as so dictated by the software.


73

Bob, K4TAX


On 4/24/2022 6:48 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 15
Date: Sun, 24 Apr 2022 15:40:30 -0500
From: Jack Brindle
To: email
Cc:"elecraft@mailman.qth.net"  
Subject: Re: [Elecraft] K4D - KPA500 Fault Question + wish
Message-ID:
Content-Type: text/plain;   charset=utf-8

If there was no recent ?HI TEMP? fault in the log, then it was not the KPA500 
that caused the display on the K4.
In that case, ask the K4 folks what may have happened.

I have never seen a HI TEMP fault with my KPA500s in normal operation, although 
I am sure others have.
I have seen it when testing?

Again, the FAN CTL is the minimum fan speed. If the fan goes above that speed, 
it will certainly slow down when
the PA cools. The amp works just fine at the default value of 0, only turning 
on the fan when it is needed.

Now, my question for everyone reading - when is it that you feel the need to 
set the fan speed above 0?

73,
Jack, W6FB


--
IF ONE EXPECTS COMPUTERS AND TECHNOLOGY TO SOLVE THEIR PROBLEMS,
ONE DOESN'T UNDERSTAND COMPUTERS AND TECHNOLOGY
AND ONE DOESN'T UNDERSTAND THEIR PROBLEMS."


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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[EMAIL]

Jack,

OK, you win.

I went back to fan speed (0) NOR and with FT8 at 400+ watts, the KPA500 
is only "doing" 56C max AND fan speed (2) is maxing also at 56C.  So, 
yes I will run the fan at (0) NOR.


Also, "rest" for NOR is 44C.

73, steve WB3LGC


On 24-Apr-22 05:21 PM, email wrote:

Jack,

Now that you ask.

I have been using the fan at (1) when I run FT8 to "get a head start" 
when I do TX.  I don't NEED to.  I like to see lower TEMP and it 
does.  I have been known to run 400W on FT8, too (FT8 is low signal 
mode not QRP) and I have been trying to get a Dallas station DE on 10m 
digital (in a skip zone).


Thanks for the help.
73, steve WB3LGC


On 4/24/22 16:40, Jack Brindle wrote:
Now, my question for everyone reading - when is it that you feel the 
need to set the fan speed above 0?


73,
Jack, W6FB


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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[john]

Is there data showing more dissipated heat with lower output in solid state
amplifiers?  I have seen similar posts on the SPE Expert list. The following
KPA1500 post shows much lower efficiency with lower power but not more lost
wattage: I am not an RF amp guru, I am just trying to understand this.
http://mailman.qth.net/pipermail/elecraft/2018-August/259502.html

John KK9A



Jack Brindle W6FB wrote:

Steve;

And, like all amplifiers, the KPA500 has a design point where efficiency is
best. Outside this design point (both high and low),
efficiency will fall off and you will find that the amp will run hotter

73,
Jack, W6FB

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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[email]

Jack,

Now that you ask.

I have been using the fan at (1) when I run FT8 to "get a head start" 
when I do TX.  I don't NEED to.  I like to see lower TEMP and it does.  
I have been known to run 400W on FT8, too (FT8 is low signal mode not 
QRP) and I have been trying to get a Dallas station DE on 10m digital 
(in a skip zone).


Thanks for the help.
73, steve WB3LGC


On 4/24/22 16:40, Jack Brindle wrote:
Now, my question for everyone reading - when is it that you feel the 
need to set the fan speed above 0?


73,
Jack, W6FB


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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Jack Brindle via Elecraft]

If there was no recent “HI TEMP” fault in the log, then it was not the KPA500 
that caused the display on the K4.
In that case, ask the K4 folks what may have happened.

I have never seen a HI TEMP fault with my KPA500s in normal operation, although 
I am sure others have. 
I have seen it when testing…

Again, the FAN CTL is the minimum fan speed. If the fan goes above that speed, 
it will certainly slow down when
the PA cools. The amp works just fine at the default value of 0, only turning 
on the fan when it is needed.

Now, my question for everyone reading - when is it that you feel the need to 
set the fan speed above 0?

73,
Jack, W6FB


> On Apr 24, 2022, at 2:51 PM, email  wrote:
> 
> 
> 
> On 4/24/22 15:06, Jack Brindle wrote:
>> Steve;
>> 
>> Use the KPA Utility to see the KPA faults. Access is under the Configuration 
>> tab, then click on “Display Fault Table”.
>> You can also save it to a file for view in a text editor, or if we ask for 
>> it, send it to tech support for analysis. 
> Thanks, I knew I had seen the fault table some place.  
> 
> What was there were early learning and adjusting (tuning) an antenna that 
> needed a 4:1 balun to match.
> 
> I will keep the utility on to see if it captures future "issues".
> 
> I DO like and USE the the KAT500 utility as it provides NICE antenna status 
> info like SWR with/without bypass.  
> 
>> The FAN CTL sets the minimum fan speed. It works in both OPER and STBY 
>> modes.  
>> Yes, it just would be nice if putting into standby, that when cooled, it 
>> would quiet down.  Yes, I can do it manually.  
>> 
>> And, like all amplifiers, the KPA500 has a design point where efficiency is 
>> best. Outside this design point (both high and low),
>> efficiency will fall off and you will find that the amp will run hotter. 
>> This is what you may have found. Remember, the PSK modes
>> tend to keep transmission active for very long times, and can really tax an 
>> amplifier. Amazingly, you may be better off running
>> the amp at higher power than yo were using to lower the stress on the PA. I 
>> am sure there are several folks on the reflector who
>> Can explain this very well. Yes, that maybe the extra heat. Thak you.  I 
>> won't pull things apart, just yet...
>> 
>> The amplifier will protect itself (IT DID, nice!) if the PA temperature goes 
>> above 90 degrees Celsius. That is the point where you will see a fault.
>> The fault log actually records the temperature when the fault occurred in 
>> its data field, which is displayed in a hexadecimal value.
>> 
>> Try looking at the fault log to see what happened on the KPA side. If you 
>> have questions, just ask.
>> 
>> 73,
>> Jack, W6FB
>> 
>> Thanks, Steve WB3LGC
>>> On Apr 24, 2022, at 1:03 PM, EMAIL   
>>> wrote:
>>> 
>>> Yesterday I got a fault message on the K4 screen. It disappeared before I 
>>> could see it fully, but I did get "tighten heatsink screws".  The fan was 
>>> working as its speed was speeding up and the KPA500 temp saw about 60+C (it 
>>> may have been higher).  I was running 100 watts PSK31.  The KPA500 did 
>>> switch to STBY (I think).
>>> 
>>> I can not find any record of what the message was.  I can not find 
>>> "heatsink screws" referenced in the K4, KPA500 or KPA1500 manuals.  Both 
>>> the K4 and KPA500 are factory built.
>>> 
>>> PSK31 has a longer duty cycle than FT8 and I was running FT8 at higher 
>>> power with out the amp temp going above 60C, earlier.  I switched to 
>>> barefoot and ran 80W PSK31 without issue.
>>> 
>>> Question 1) Before I take the KPA500 apart, is this a problem or just duty 
>>> cycle?  I would think the KPA500 would be able to handle 100W key down.
>>> 
>>> Question 2) I saved the K4 backup and diagnostic logs to USB disk (the next 
>>> day).  I could NOT find anything that looked like the error messages.  I 
>>> find many messages disappear before I get a chance to read them.
>>> 
>>> Wish 1) KPA500 add FAN CTL for both OPER and STBY or set STBY to run at NOR 
>>> and OPER to be adjustable.
>>> 
>>> Wish 2) K4, allow checking date/time for all past error messages.  I may 
>>> have had a KPA500 over temp message while long winded on SSB (but only 
>>> 200W)?
>>> 
>>> Wish 3) K4, HOLD error messages until "confirmed".  Messages like KPA500 
>>> on/off (info) only need to be short time (??), but if away (maybe confirm). 
>>>  Either way "this" will be an issue for  the contesters, so have a way to 
>>> save for later recall, as in write to USB if one is installed.  Fn could 
>>> write to USB disk with time stamp?  OR, are there documents on how to read 
>>> the diagnostic logs?
>>> 
>>> 
>>> 73, steve WB3LGC
>>> 
>>> I will also send to support if no one has a good idea about the fault.
>>> 
>>> __
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft 
>>> 
>>> Help: 

Re: [Elecraft] K4D - KPA500 Fault Question + wish

[email]

On 4/24/22 15:06, Jack Brindle wrote:

Steve;

Use the KPA Utility to see the KPA faults. Access is under the Configuration 
tab, then click on “Display Fault Table”.
You can also save it to a file for view in a text editor, or if we ask for it, 
send it to tech support for analysis.


Thanks, I knew I had seen the fault table some place.

What was there were early learning and adjusting (tuning) an antenna 
that needed a 4:1 balun to match.


I will keep the utility on to see if it captures future "issues".

I DO like and USE the the KAT500 utility as it provides NICE antenna 
status info like SWR with/without bypass.


The FAN CTL sets the minimum fan speed. It works in both OPER and STBY modes.Yes, it just would be nice if putting into standby, that when cooled, 
it would quiet down. Yes, I can do it manually.


And, like all amplifiers, the KPA500 has a design point where efficiency is 
best. Outside this design point (both high and low),
efficiency will fall off and you will find that the amp will run hotter. This 
is what you may have found. Remember, the PSK modes
tend to keep transmission active for very long times, and can really tax an 
amplifier. Amazingly, you may be better off running
the amp at higher power than yo were using to lower the stress on the PA. I am 
sure there are several folks on the reflector who
Can explain this very well.Yes, that maybe the extra heat. Thak you. I won't pull things apart, 
just yet...


The amplifier will protect itself(IT DID, nice!)  if the PA temperature goes 
above 90 degrees Celsius. That is the point where you will see a fault.
The fault log actually records the temperature when the fault occurred in its 
data field, which is displayed in a hexadecimal value.

Try looking at the fault log to see what happened on the KPA side. If you have 
questions, just ask.

73,
Jack, W6FB

Thanks, Steve WB3LGC

On Apr 24, 2022, at 1:03 PM, EMAIL  wrote:

Yesterday I got a fault message on the K4 screen. It disappeared before I could see it 
fully, but I did get "tighten heatsink screws".  The fan was working as its 
speed was speeding up and the KPA500 temp saw about 60+C (it may have been higher).  I 
was running 100 watts PSK31.  The KPA500 did switch to STBY (I think).

I can not find any record of what the message was.  I can not find "heatsink 
screws" referenced in the K4, KPA500 or KPA1500 manuals.  Both the K4 and KPA500 are 
factory built.

PSK31 has a longer duty cycle than FT8 and I was running FT8 at higher power 
with out the amp temp going above 60C, earlier.  I switched to barefoot and ran 
80W PSK31 without issue.

Question 1) Before I take the KPA500 apart, is this a problem or just duty 
cycle?  I would think the KPA500 would be able to handle 100W key down.

Question 2) I saved the K4 backup and diagnostic logs to USB disk (the next 
day).  I could NOT find anything that looked like the error messages.  I find 
many messages disappear before I get a chance to read them.

Wish 1) KPA500 add FAN CTL for both OPER and STBY or set STBY to run at NOR and 
OPER to be adjustable.

Wish 2) K4, allow checking date/time for all past error messages.  I may have 
had a KPA500 over temp message while long winded on SSB (but only 200W)?

Wish 3) K4, HOLD error messages until "confirmed".  Messages like KPA500 on/off (info) 
only need to be short time (??), but if away (maybe confirm).  Either way "this" will be 
an issue for  the contesters, so have a way to save for later recall, as in write to USB if one is 
installed.  Fn could write to USB disk with time stamp?  OR, are there documents on how to read the 
diagnostic logs?


73, steve WB3LGC

I will also send to support if no one has a good idea about the fault.

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Re: [Elecraft] K4D - KPA500 Fault Question + wish

[Jack Brindle via Elecraft]

Steve;

Use the KPA Utility to see the KPA faults. Access is under the Configuration 
tab, then click on “Display Fault Table”.
You can also save it to a file for view in a text editor, or if we ask for it, 
send it to tech support for analysis. 

The FAN CTL sets the minimum fan speed. It works in both OPER and STBY modes.

And, like all amplifiers, the KPA500 has a design point where efficiency is 
best. Outside this design point (both high and low),
efficiency will fall off and you will find that the amp will run hotter. This 
is what you may have found. Remember, the PSK modes
tend to keep transmission active for very long times, and can really tax an 
amplifier. Amazingly, you may be better off running
the amp at higher power than yo were using to lower the stress on the PA. I am 
sure there are several folks on the reflector who
Can explain this very well.

The amplifier will protect itself if the PA temperature goes above 90 degrees 
Celsius. That is the point where you will see a fault.
The fault log actually records the temperature when the fault occurred in its 
data field, which is displayed in a hexadecimal value.

Try looking at the fault log to see what happened on the KPA side. If you have 
questions, just ask.

73,
Jack, W6FB


> On Apr 24, 2022, at 1:03 PM, EMAIL  wrote:
> 
> Yesterday I got a fault message on the K4 screen. It disappeared before I 
> could see it fully, but I did get "tighten heatsink screws".  The fan was 
> working as its speed was speeding up and the KPA500 temp saw about 60+C (it 
> may have been higher).  I was running 100 watts PSK31.  The KPA500 did switch 
> to STBY (I think).
> 
> I can not find any record of what the message was.  I can not find "heatsink 
> screws" referenced in the K4, KPA500 or KPA1500 manuals.  Both the K4 and 
> KPA500 are factory built.
> 
> PSK31 has a longer duty cycle than FT8 and I was running FT8 at higher power 
> with out the amp temp going above 60C, earlier.  I switched to barefoot and 
> ran 80W PSK31 without issue.
> 
> Question 1) Before I take the KPA500 apart, is this a problem or just duty 
> cycle?  I would think the KPA500 would be able to handle 100W key down.
> 
> Question 2) I saved the K4 backup and diagnostic logs to USB disk (the next 
> day).  I could NOT find anything that looked like the error messages.  I find 
> many messages disappear before I get a chance to read them.
> 
> Wish 1) KPA500 add FAN CTL for both OPER and STBY or set STBY to run at NOR 
> and OPER to be adjustable.
> 
> Wish 2) K4, allow checking date/time for all past error messages.  I may have 
> had a KPA500 over temp message while long winded on SSB (but only 200W)?
> 
> Wish 3) K4, HOLD error messages until "confirmed".  Messages like KPA500 
> on/off (info) only need to be short time (??), but if away (maybe confirm).  
> Either way "this" will be an issue for  the contesters, so have a way to save 
> for later recall, as in write to USB if one is installed.  Fn could write to 
> USB disk with time stamp?  OR, are there documents on how to read the 
> diagnostic logs?
> 
> 
> 73, steve WB3LGC
> 
> I will also send to support if no one has a good idea about the fault.
> 
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[Elecraft] K4D - KPA500 Fault Question + wish

[EMAIL]

Yesterday I got a fault message on the K4 screen. It disappeared before 
I could see it fully, but I did get "tighten heatsink screws".  The fan 
was working as its speed was speeding up and the KPA500 temp saw about 
60+C (it may have been higher).  I was running 100 watts PSK31.  The 
KPA500 did switch to STBY (I think).


I can not find any record of what the message was.  I can not find 
"heatsink screws" referenced in the K4, KPA500 or KPA1500 manuals.  Both 
the K4 and KPA500 are factory built.


PSK31 has a longer duty cycle than FT8 and I was running FT8 at higher 
power with out the amp temp going above 60C, earlier.  I switched to 
barefoot and ran 80W PSK31 without issue.


Question 1) Before I take the KPA500 apart, is this a problem or just 
duty cycle?  I would think the KPA500 would be able to handle 100W key 
down.


Question 2) I saved the K4 backup and diagnostic logs to USB disk (the 
next day).  I could NOT find anything that looked like the error 
messages.  I find many messages disappear before I get a chance to read 
them.


Wish 1) KPA500 add FAN CTL for both OPER and STBY or set STBY to run at 
NOR and OPER to be adjustable.


Wish 2) K4, allow checking date/time for all past error messages.  I may 
have had a KPA500 over temp message while long winded on SSB (but only 
200W)?


Wish 3) K4, HOLD error messages until "confirmed".  Messages like KPA500 
on/off (info) only need to be short time (??), but if away (maybe 
confirm).  Either way "this" will be an issue for  the contesters, so 
have a way to save for later recall, as in write to USB if one is 
installed.  Fn could write to USB disk with time stamp?  OR, are there 
documents on how to read the diagnostic logs?



73, steve WB3LGC

I will also send to support if no one has a good idea about the fault.

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