[Elecraft] KPA-500 Failure

[Dick Bingham]

Hello Rick (NK7I) and Andy (K3WYC) - Tnx replies

"Message: 17
Date: Wed, 24 Apr 2024 14:11:28 +
From: Andy Durbin 
To: "elecraft@mailman.qth.net" 
Subject: [Elecraft]  KPA-500 Failure
Message-ID:
<
dm4pr10mb6791e0db00b79830385f5cd28c...@dm4pr10mb6791.namprd10.prod.outlook.com
>

Content-Type: text/plain; charset="iso-8859-1"

"With the OPER light GREEN and slowly increasing the RF drive level to the
amp, there is a point where an internal relay 'click' can be heard, the
50-watt LED on the top row of LEDs turns red and the FAULT light turns red."

All the KPA500 LED are single color.  The 50 W LED is either lit green or
not lit.  Did it appear to be red because of light leakage from the FAULT
LED?

Some quite detailed discussion of KPA500 failure modes on the groups.io
 forum:

https://groups.io/g/KPA500/topics

73,
Andy, k3wyc "

IF I remember correctly, the entire top row of LEDs flashed red in color
when the failure happened.

After removing the top cover, the PA assy is visible but there appears to
be no easy way access it due to a large bolt connecting the round
transformer to the bottom plate. Will have to access the home-builder
manual to figure out how to inspect the PA assembly.

TU for the reply  --  Dick/w7wkr
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[Elecraft] KPA-500 Failure

[Andy Durbin]

"With the OPER light GREEN and slowly increasing the RF drive level to the amp, 
there is a point where an internal relay 'click' can be heard, the 50-watt LED 
on the top row of LEDs turns red and the FAULT light turns red."

All the KPA500 LED are single color.  The 50 W LED is either lit green or not 
lit.  Did it appear to be red because of light leakage from the FAULT LED?

Some quite detailed discussion of KPA500 failure modes on the groups.io forum:

https://groups.io/g/KPA500/topics

73,
Andy, k3wyc

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Re: [Elecraft] KPA-500 Failure

[Rick NK7I]

It sounds like blown FETs.  It may be time to ship it to CA where 
any/all upgrades can be done as well as repair.


They're a little backed up, so it may take a few weeks.  Parts and shop 
time too of course.


Call the techs to discuss it and get an RSA and ask if they want you to 
pull the transformer to save shipping weight/cost.  You MUST have the 
RSA (write it on the box, a cover letter inside and with any email 
discussion once it's issued).


The tech indicated that damage to the FETs may be cumulative over time, 
so it may not be THIS event.  But it won't hurt to go through the entire 
antenna and feed system to be sure.


Or you can dive in to repair it; if you feel qualified.

Sorry, been there too.

Rick nk7i

On 4/23/2024 6:52 PM, Dick Bingham wrote:

Greeting to everyone

I have read the KPA500 operator manual in hopes of solving my
issue and have found nothing that solves/fixes the problem.

This amplifier has been a workhorse for many years and today
after the KAT500 antenna tuner searched/found a 'match' for a new
antenna, I selected OPER on the KPA500, and applied drive power
to the amplifier.

Immediately, the amplifier displayed a momentary overload indicated
by the top row of LEDs (power indicator ones) all flashing ON after
which, the amp FAULTED and shut down. The RF drive level was
around 20-watts and should have provided about 300-watts output at
the time this occurred.

I tapped the OPER/STBY button and tried to activate the amplifier and
found there is no response to incoming RF drive.

I removed/reapplied 'mains' power, pressed the 'EDIT' and ON keys
simultaneously to reset everything and that did not correct the problem.

The power supply voltage is in spec so no issue there.

With the OPER light GREEN and slowly increasing the RF drive level
to the amp, there is a point where an internal relay 'click' can be heard,
the 50-watt LED on the top row of LEDs turns red and the FAULT light
turns red.

I could not detect any sign of smoke (nose/eyes) so have not opened
the case to look for burned parts.

Before I open the 'case' and look for obvious problems, any observations
or suggestions received here will be appreciated. Kinda looks like blown
amp power FETs.

Dick - w7wkr
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[Elecraft] KPA-500 Failure

[Dick Bingham]

Greeting to everyone

I have read the KPA500 operator manual in hopes of solving my
issue and have found nothing that solves/fixes the problem.

This amplifier has been a workhorse for many years and today
after the KAT500 antenna tuner searched/found a 'match' for a new
antenna, I selected OPER on the KPA500, and applied drive power
to the amplifier.

Immediately, the amplifier displayed a momentary overload indicated
by the top row of LEDs (power indicator ones) all flashing ON after
which, the amp FAULTED and shut down. The RF drive level was
around 20-watts and should have provided about 300-watts output at
the time this occurred.

I tapped the OPER/STBY button and tried to activate the amplifier and
found there is no response to incoming RF drive.

I removed/reapplied 'mains' power, pressed the 'EDIT' and ON keys
simultaneously to reset everything and that did not correct the problem.

The power supply voltage is in spec so no issue there.

With the OPER light GREEN and slowly increasing the RF drive level
to the amp, there is a point where an internal relay 'click' can be heard,
the 50-watt LED on the top row of LEDs turns red and the FAULT light
turns red.

I could not detect any sign of smoke (nose/eyes) so have not opened
the case to look for burned parts.

Before I open the 'case' and look for obvious problems, any observations
or suggestions received here will be appreciated. Kinda looks like blown
amp power FETs.

Dick - w7wkr
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[Elecraft] KPA 500/KAT 500 Seemingly on the Fritz

[Jim Ewing]

Dear everyone,

This morning while I was running a CW net, using a VibroPlex Lightning bug,
my KPA 500 seemingly went on the Fritz. I was running it at 300 Watts, on
7.123 MHz, paired with my K3 using the smart cables, and it was working
perfectly until about 10 minutes into the net.  Whereupon it stopped
putting out power. The antenna to which it was connected via the KAT500
tuner, was a 160m OCFD. I subsequently checked the antenna with my Rig
Expert analyzer to confirm that the SWR on the antenna at that frequency is
1.5.

When the KPA 500 stopped putting out power, the following were what I
noted: When I went key down, I saw the little asterisk on the LCD screen of
the KPA 500 appear corresponding to my key, but the green/yellow/red LED
bars over to the right stayed dark. Readings on the LED screen when I
pushed the appropriate buttons (with key down): PWR = 0; Temp = 23C;
current = .9; HV = 68.2; keying asterisk appeared when I went key down. I
checked the tightness of the smart cable connections on back of tuner, amp
and K3, powered everything down and then back up, and the problem persisted.

When the KPA 500 stopped putting out power, I put it in STBY as well as the
KAT 500 in bypass, and continued on with the net, and I was getting out as
confirmed by my 599 signal on an SDR in KY which I monitor during the net.

Given that the little keying asterisk shows up when I go key down, but the
colored LED bar does not light nor do I hear a signal on the KY SDR when
the KPA 500 is in Operate mode, it seems like the KPA 500 knows it's
receiving a key down signal from the K3, but for some reason it just isn't
putting out any power.

This amp is new to me, but I am unnerved somewhat because it stopped
working in the middle of the net after working perfectly for about 10
minutes. Apologies if I am missing something totally obvious, but does
anyone have clues as to what may be the issue, or what I might do to
resolve the problem?

Thank you.

Jim Ewing N4TMM
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Re: [Elecraft] KPA 500 Question

[G4GNX]

Also, many people forget that the KAT500 works on RX as well as TX and provides 
a band-pass filter which changes position across tuning segments.
If you’re using the KAT500 without the Aux cable and the main TX antenna for 
RX, as soon as you tune the RX away from the current tuned segment, the RX path 
is no longer at optimum.

73,
Alan - G4GNX
South Coast UK
Elecraft K4D / KPA500 / KAT500 / IC-9700




> On 14 Nov 2023, at 02:52, Pete Smith N4ZR  wrote:
> 
> I have a KPA-1500, and followed the manual's instruction to run an Aux cable 
> between my K-3's ACC jack (on the KIO3B) and the KPA-1500.  I prefer to have 
> the band changing already accomplished before I go key down, even for just a 
> dit.
> 
> 73, Pete N4ZR
> 

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Re: [Elecraft] KPA 500 Question

[Pete Smith N4ZR]

I have a KPA-1500, and followed the manual's instruction to run an Aux 
cable between my K-3's ACC jack (on the KIO3B) and the KPA-1500.  I 
prefer to have the band changing already accomplished before I go key 
down, even for just a dit.


73, Pete N4ZR

On 11/13/2023 7:14 PM, Jim Brown wrote:

I have cables that control the amplifier for each radio.


By default, the KPA500, KPA1500, and KAT500 all have 
near-instantaneous frequency-detection. They switch very quickly to 
the right band, and the tuners will recall previous antenna tunings 
for the detected frequency. All it takes is a dit or a tap on the mic. 
That's in addition to the front panel band switches. I own all three, 
and have never used an AUX cable with any of them.


73, Jim K9YC



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Re: [Elecraft] KPA 500 Question

[Jim Brown]

I have cables that control the amplifier for each radio.


By default, the KPA500, KPA1500, and KAT500 all have near-instantaneous 
frequency-detection. They switch very quickly to the right band, and the 
tuners will recall previous antenna tunings for the detected frequency. 
All it takes is a dit or a tap on the mic. That's in addition to the 
front panel band switches. I own all three, and have never used an AUX 
cable with any of them.


73, Jim K9YC



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Re: [Elecraft] KPA 500 Question

[W3FPR]

Doug,

You will have to use a switch that changes all 15 conductors.  VGA 
switches may not implement all conductors and worse yet, some may be 
connected together to common (ground).


73,
Don W3FPR

On 11/13/2023 3:18 PM, Doug Millar via Elecraft wrote:

  I am trying to use my K3 and a Yaesu FTDX10 with my KPA 500. I have cables 
that control the amplifier for each radio. What can I use for a switch box to 
switch the cables into the amp? A VGA switch did not work.   Doug K6JEY


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[Elecraft] KPA 500 Question

[Doug Millar via Elecraft]

 I am trying to use my K3 and a Yaesu FTDX10 with my KPA 500. I have cables 
that control the amplifier for each radio. What can I use for a switch box to 
switch the cables into the amp? A VGA switch did not work.   Doug K6JEY
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Re: [Elecraft] KPA 500 Erratic Band Changes

[Jack Brindle via Elecraft]

Dave;

Do you get the Operate message on the K3 display before the band change? 
Might the K3 be transmitting when you hit the OPER button on the KPA?

Use the KPA Utility to get a fast log file and send it my way. I am very 
interested in seeing the KPA’s current settings. I’m really puzzled at what 
might be going on.

73,
Jack, W6FB


> On Mar 26, 2023, at 10:09 PM, Dave  wrote:
> 
> K3 – KAT500 – KPA500 setup using AUX cables (2) to interconnect. All 3 
> devices seem to be talking to each other just fine but when I go from STBY to 
> OPER on the amp, it changes bands and changes the band on the K3. It most 
> often goes to 28Mhz but not every time. I checked both cables for continuity 
> before connecting everything and they look fine. Has anyone seen anything 
> similar to this or experienced the same thing? Tnx es 73, Dave N8AG
> 
> Sent from Mail for Windows
> 
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[Elecraft] KPA 500 Erratic Band Changes

[Dave]

K3 – KAT500 – KPA500 setup using AUX cables (2) to interconnect. All 3 devices 
seem to be talking to each other just fine but when I go from STBY to OPER on 
the amp, it changes bands and changes the band on the K3. It most often goes to 
28Mhz but not every time. I checked both cables for continuity before 
connecting everything and they look fine. Has anyone seen anything similar to 
this or experienced the same thing? Tnx es 73, Dave N8AG

Sent from Mail for Windows

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Re: [Elecraft] KPA 500: No Output

[Lyn Norstad]

Dave -

Looking at your very nice website and the "Radio-end station setup," I'm
wondering why you are using an external antenna switch?  In my experience,
especially for remote operation, you'll generally have a much more
fool-proof installation using the KAT500's internal antenna switch.  The way
you're doing it, the KAT has no way to know which antenna it is supposed to
be matching - and thereby could lead to many problems - including damage to
the finals.

73
Lyn, WØLEN


-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of dave ingebright
Sent: Tuesday, December 13, 2022 9:47 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA 500: No Output

Hello-- I have a 3 yr old KPA500 that has just exhibited it's first problem.
No amplification! I am remote controlling it via the remote client over the
internet from 2000 miles away. Nothing has changed in the remote shack and
no wiring has been disturbed. There is no output from the KPA on any band. I
can see the 72 Volt B+, and the temp of the heatsink, and I can control the
fan speed, so I have control of the unit. The client shows the exciter power
through the amp and the SWR. There are no alarms and I have hit alarm reset
and had the power plug pulled and reset.  I'd guess the PTT line is somehow
open but... asking if anyone has had a similar problem.
tnx de dave
WB7ELY
My KPA500 page: https://www.valhallatreefarm.com/WB7ELY/kpa500/kpa500.htm 
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Re: [Elecraft] KPA 500: No Output

[Dave (NK7Z)]

If you have a camera pointing at the amp, look for the "*" when you key 
down...


73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 12/13/22 07:47, dave ingebright wrote:

Hello-- I have a 3 yr old KPA500 that has just exhibited it's first problem. No 
amplification! I am remote controlling it via the remote client over the 
internet from 2000 miles away. Nothing has changed in the remote shack and no 
wiring has been disturbed. There is no output from the KPA on any band. I can 
see the 72 Volt B+, and the temp of the heatsink, and I can control the fan 
speed, so I have control of the unit. The client shows the exciter power 
through the amp and the SWR. There are no alarms and I have hit alarm reset and 
had the power plug pulled and reset.  I'd guess the PTT line is somehow open 
but... asking if anyone has had a similar problem.
tnx de dave
WB7ELY
My KPA500 page: https://www.valhallatreefarm.com/WB7ELY/kpa500/kpa500.htm
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[Elecraft] KPA 500: No Output

[dave ingebright]

Hello-- I have a 3 yr old KPA500 that has just exhibited it's first problem. No 
amplification! I am remote controlling it via the remote client over the 
internet from 2000 miles away. Nothing has changed in the remote shack and no 
wiring has been disturbed. There is no output from the KPA on any band. I can 
see the 72 Volt B+, and the temp of the heatsink, and I can control the fan 
speed, so I have control of the unit. The client shows the exciter power 
through the amp and the SWR. There are no alarms and I have hit alarm reset and 
had the power plug pulled and reset.  I'd guess the PTT line is somehow open 
but... asking if anyone has had a similar problem.
tnx de dave
WB7ELY
My KPA500 page: https://www.valhallatreefarm.com/WB7ELY/kpa500/kpa500.htm 
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Louandzip via Elecraft]

 FWIW, the FTdx101 series has among the very best CW bandwidths when set to 8 
msec risetime.  It beats the Kenwood TS890S by a good margin. I have a 60wpm 
spectrum analyzer sweep showing that.  It was improved with the May 2021 
firmware release which was after ARRL testing.  This is a far cry from most all 
prior Yaesu rigs.  

On Thursday, July 28, 2022 at 11:05:08 AM MDT, Lyn Norstad 
 wrote:  
 
 Thanks for the data, Jim (and Victor) -

Even though it significantly pre-dates the IC-7300, I respect your work and
will assume it has relevance.

So I am resetting the CW Rise Time to 8ms ... its slowest setting.

That being said, I so seldom use CW it's pretty much a non-issue for me.

73
Lyn, WØLEN



-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Thursday, July 28, 2022 2:55 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA-500 timing settings IC-7300

On 7/27/2022 12:08 PM, Lyn Norstad wrote:
> CW Rise Time set to the default, 4ms (range 2ms - 8ms).

This is MUCH too fast, very clicky. Even the slowest is much too clicky.

See my analysis of ARRL Lab Test results done in 2014. This is all THEIR 
data, that they sent me in electronic form.

  http://k9yc.com/TXNoise.pdf

Kenwood is the cleanest of the JA transceivers, but the cleanest ones by 
a lot are Elecraft K3 and later, where they developed non-adjustable 
keying which Wayne has describes as "sigmoidal" or "raised cosine" 
shaping. He introduced it in 2007; Flex 6000 series when tested by ARRL 
(after my report) was pretty nasty, but they subsequently followed 
Elecraft's lead and got a LOT cleaner.

What we CALL CW is really 100% amplitude modulation of a carrier by a 
rectangular wave train, and the harmonics from the transition excite IMD 
that is heard as clicks. I demonstrated this in another report presented 
using Power Point, but not intented as a Power Point talk. It's simply a 
convenient way of presenting the data.

http://k9yc.com/FTDX5000_Report.pdf

Slide 13 shows the unmodulated carrier, slide 14 shows an FTDX5000 
sending dits at roughly 30 wpm.

I purposely leaked an early version of this report to someone I 
suspected would make sure that Yaesu saw it. Within days of my 
publishing it, Yaesu released the firmware update documented by later 
slides.

The only reason for giving hams adjustable rise time is MARKETING!

BTW -- there are other very slick elements of Wayne's designs that 
drastically reduce their transmitted and received phase noise, most of 
which date back to 2007 in the earliest K3.

You can see my earlier measurements of a neighbor's 7600 as he varied 
rise time. He's a GOOD neighbor; I have another with a 7600 who, for 
years, chewed up 10-20 kHz of the band on CW; K6XX and I, both running a 
K3 legal limit, 3 miles apart, can work within 500 Hz of each other and 
hear each other as simply another loud signal. These data are with the 
original K3, long before the improved synth board.

73, Jim K9YC

73, Jim K9YC

73, Jim K9YC
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Lyn Norstad]

Thanks for the data, Jim (and Victor) -

Even though it significantly pre-dates the IC-7300, I respect your work and
will assume it has relevance.

So I am resetting the CW Rise Time to 8ms ... its slowest setting.

That being said, I so seldom use CW it's pretty much a non-issue for me.

73
Lyn, WØLEN



-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Thursday, July 28, 2022 2:55 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA-500 timing settings IC-7300

On 7/27/2022 12:08 PM, Lyn Norstad wrote:
> CW Rise Time set to the default, 4ms (range 2ms - 8ms).

This is MUCH too fast, very clicky. Even the slowest is much too clicky.

See my analysis of ARRL Lab Test results done in 2014. This is all THEIR 
data, that they sent me in electronic form.

  http://k9yc.com/TXNoise.pdf

Kenwood is the cleanest of the JA transceivers, but the cleanest ones by 
a lot are Elecraft K3 and later, where they developed non-adjustable 
keying which Wayne has describes as "sigmoidal" or "raised cosine" 
shaping. He introduced it in 2007; Flex 6000 series when tested by ARRL 
(after my report) was pretty nasty, but they subsequently followed 
Elecraft's lead and got a LOT cleaner.

What we CALL CW is really 100% amplitude modulation of a carrier by a 
rectangular wave train, and the harmonics from the transition excite IMD 
that is heard as clicks. I demonstrated this in another report presented 
using Power Point, but not intented as a Power Point talk. It's simply a 
convenient way of presenting the data.

http://k9yc.com/FTDX5000_Report.pdf

Slide 13 shows the unmodulated carrier, slide 14 shows an FTDX5000 
sending dits at roughly 30 wpm.

I purposely leaked an early version of this report to someone I 
suspected would make sure that Yaesu saw it. Within days of my 
publishing it, Yaesu released the firmware update documented by later 
slides.

The only reason for giving hams adjustable rise time is MARKETING!

BTW -- there are other very slick elements of Wayne's designs that 
drastically reduce their transmitted and received phase noise, most of 
which date back to 2007 in the earliest K3.

You can see my earlier measurements of a neighbor's 7600 as he varied 
rise time. He's a GOOD neighbor; I have another with a 7600 who, for 
years, chewed up 10-20 kHz of the band on CW; K6XX and I, both running a 
K3 legal limit, 3 miles apart, can work within 500 Hz of each other and 
hear each other as simply another loud signal. These data are with the 
original K3, long before the improved synth board.

73, Jim K9YC

73, Jim K9YC

73, Jim K9YC
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Jim Brown]

On 7/27/2022 12:08 PM, Lyn Norstad wrote:

CW Rise Time set to the default, 4ms (range 2ms - 8ms).


This is MUCH too fast, very clicky. Even the slowest is much too clicky.

See my analysis of ARRL Lab Test results done in 2014. This is all THEIR 
data, that they sent me in electronic form.


 http://k9yc.com/TXNoise.pdf

Kenwood is the cleanest of the JA transceivers, but the cleanest ones by 
a lot are Elecraft K3 and later, where they developed non-adjustable 
keying which Wayne has describes as "sigmoidal" or "raised cosine" 
shaping. He introduced it in 2007; Flex 6000 series when tested by ARRL 
(after my report) was pretty nasty, but they subsequently followed 
Elecraft's lead and got a LOT cleaner.


What we CALL CW is really 100% amplitude modulation of a carrier by a 
rectangular wave train, and the harmonics from the transition excite IMD 
that is heard as clicks. I demonstrated this in another report presented 
using Power Point, but not intented as a Power Point talk. It's simply a 
convenient way of presenting the data.


http://k9yc.com/FTDX5000_Report.pdf

Slide 13 shows the unmodulated carrier, slide 14 shows an FTDX5000 
sending dits at roughly 30 wpm.


I purposely leaked an early version of this report to someone I 
suspected would make sure that Yaesu saw it. Within days of my 
publishing it, Yaesu released the firmware update documented by later 
slides.


The only reason for giving hams adjustable rise time is MARKETING!

BTW -- there are other very slick elements of Wayne's designs that 
drastically reduce their transmitted and received phase noise, most of 
which date back to 2007 in the earliest K3.


You can see my earlier measurements of a neighbor's 7600 as he varied 
rise time. He's a GOOD neighbor; I have another with a 7600 who, for 
years, chewed up 10-20 kHz of the band on CW; K6XX and I, both running a 
K3 legal limit, 3 miles apart, can work within 500 Hz of each other and 
hear each other as simply another loud signal. These data are with the 
original K3, long before the improved synth board.


73, Jim K9YC

73, Jim K9YC

73, Jim K9YC
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Victor Rosenthal]

The KPA would be fine with 8ms delay, and 4ms rise time is most likely
clicky. 6 would be better.

Victor 4X6GP

On Wed, Jul 27, 2022, 22:10 Lyn Norstad  wrote:

> Tom -
>
> I am running the 7300 with KPA/KAT500 and have the TX Delay on the 7300
> set for 15ms on both HF and 50MHz (the range is 0 - 30ms), and the CW Rise
> Time set to the default, 4ms (range 2ms - 8ms).
>
> On the KPA500, I have TR set to 00.
>
> Hope that helps.
>
> 73
> Lyn, WØLEN
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net [mailto:
> elecraft-boun...@mailman.qth.net] On Behalf Of Tom N4LSJ
> Sent: Tuesday, July 26, 2022 8:39 PM
> To: Elecraft@mailman.qth.net
> Subject: [Elecraft] KPA-500 timing settings IC-7300
>
> I've been on the internet and can find IC-7300 TX Delay, CW Rise Time
> settings for other amplifiers pretty easily.  There don't appear to be
> any for -specifically- the IC-7300 and KPA-500.  Are there "officially
> sanctioned" settings for that combination?  I feel it may be overkill to
> use 30ms when 10ms TX delay may suffice.  Is there also a suggested CW
> rise time from Elecraft?
>
> The KPA-500 also has a "TR TIME" settings from 0 to 50 as well. Does
> that need to be set for the 7300?
>
> I -DO- have a KAT-500 and the whole get-up is hooked as per the
> documentation on Elecraft's FTP site, e.g. the key line going to the
> tuner, then the amp.  That document says nothing regarding timing.
>
> 73 to all!
>
> Tom N4LSJ.
>
>
>
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Lyn Norstad]

Tom -

I am running the 7300 with KPA/KAT500 and have the TX Delay on the 7300 set for 
15ms on both HF and 50MHz (the range is 0 - 30ms), and the CW Rise Time set to 
the default, 4ms (range 2ms - 8ms).

On the KPA500, I have TR set to 00.

Hope that helps.

73
Lyn, WØLEN

-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Tom N4LSJ
Sent: Tuesday, July 26, 2022 8:39 PM
To: Elecraft@mailman.qth.net
Subject: [Elecraft] KPA-500 timing settings IC-7300

I've been on the internet and can find IC-7300 TX Delay, CW Rise Time 
settings for other amplifiers pretty easily.  There don't appear to be 
any for -specifically- the IC-7300 and KPA-500.  Are there "officially 
sanctioned" settings for that combination?  I feel it may be overkill to 
use 30ms when 10ms TX delay may suffice.  Is there also a suggested CW 
rise time from Elecraft?

The KPA-500 also has a "TR TIME" settings from 0 to 50 as well. Does 
that need to be set for the 7300?

I -DO- have a KAT-500 and the whole get-up is hooked as per the 
documentation on Elecraft's FTP site, e.g. the key line going to the 
tuner, then the amp.  That document says nothing regarding timing.

73 to all!

Tom N4LSJ.



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Re: [Elecraft] KPA-500 timing settings IC-7300

[Brian D]

t5he ic7300 does have an RF tail, which has recently been discussed in the
ic7300 group on groups.io

extract from there:


Hello Adam,

As you requested, I have updated the page with the new 'scope trace.
http://wb6bbb.com/Icom_IC-7300/index.html

The entire web page, including thumbnail and full-size images, is available
in this 52.1 MB zip file:
http://wb6bbb.com/Icom_IC-7300/Icom%20IC-7300%20Hot-switch%20Mitigation.zip

Thank you for your support.

Best regards,
Larry
WB6BBB


PS: I've attached a PDF file of the main page (without the Disclaimer page),
but unlike Adam's PDF, the images do not link to the web page when clicked.




Jack Brindle via Elecraft  wrote:

> The TRTime parameter sets the time the KPA takes to transition from TX to
> RX - this is specifically for transmitters that may continue to output RF
> for a short time after their PTT line becomes inactive. For the K3, K3S
> and K4 that time is very short, which means the KPA can transition
> immediately from RX to TX (it takes less than 1 mSec). There are some
> transceivers that start the key up process when the PTT line becomes
> inactive. I don’t know what the 7300 does in this case - hopefully others
> on the list have this information and can tell us.
> 


-- 
Brian D 
G3VGZ G8AOE G3T
IO94im
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Re: [Elecraft] KPA-500 timing settings IC-7300

[Jack Brindle via Elecraft]

The KPA500 is a QSK amplifier. It switches from RX to TX very rapidly (about 2 
mSec) in order to allow QSK operation of the station.

The TRTime parameter sets the time the KPA takes to transition from TX to RX - 
this is specifically for transmitters that may continue to output RF for a 
short time after their PTT line becomes inactive.
For the K3, K3S and K4 that time is very short, which means the KPA can 
transition immediately from RX to TX (it takes less than 1 mSec). There are 
some transceivers that start the key up process when the PTT line becomes 
inactive. I don’t know what the 7300 does in this case - hopefully others on 
the list have this information and can tell us.

73,
Jack, W6FB


> On Jul 26, 2022, at 8:39 PM, Tom N4LSJ  wrote:
> 
> I've been on the internet and can find IC-7300 TX Delay, CW Rise Time 
> settings for other amplifiers pretty easily.  There don't appear to be any 
> for -specifically- the IC-7300 and KPA-500.  Are there "officially 
> sanctioned" settings for that combination?  I feel it may be overkill to use 
> 30ms when 10ms TX delay may suffice.  Is there also a suggested CW rise time 
> from Elecraft?
> 
> The KPA-500 also has a "TR TIME" settings from 0 to 50 as well. Does that 
> need to be set for the 7300?
> 
> I -DO- have a KAT-500 and the whole get-up is hooked as per the documentation 
> on Elecraft's FTP site, e.g. the key line going to the tuner, then the amp.  
> That document says nothing regarding timing.
> 
> 73 to all!
> 
> Tom N4LSJ.
> 
> 
> 
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[Elecraft] KPA-500 timing settings IC-7300

[Tom N4LSJ]

I've been on the internet and can find IC-7300 TX Delay, CW Rise Time 
settings for other amplifiers pretty easily.  There don't appear to be 
any for -specifically- the IC-7300 and KPA-500.  Are there "officially 
sanctioned" settings for that combination?  I feel it may be overkill to 
use 30ms when 10ms TX delay may suffice.  Is there also a suggested CW 
rise time from Elecraft?


The KPA-500 also has a "TR TIME" settings from 0 to 50 as well. Does 
that need to be set for the 7300?


I -DO- have a KAT-500 and the whole get-up is hooked as per the 
documentation on Elecraft's FTP site, e.g. the key line going to the 
tuner, then the amp.  That document says nothing regarding timing.


73 to all!

Tom N4LSJ.



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Re: [Elecraft] KPA-500 Line-Voltage Issues

[Victor Rosenthal 4X6GP]

I had to add a soft-start relay to my Astron RS-70A power supply to keep 
it from popping a 16a breaker when using it on 50 Hz. But otherwise it 
works fine with the transformer wired for 240v.


73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/

On 07-Jul-2022 01:01, Josh Fiden wrote:

Transformer core can saturate if line frequency is too low. Except
I’d be certain KPA-500 uses the same transformer for export to 50Hz
countries so your variations are fine.

Many years ago when I was young & dumb discovered this the hard way.
Customers would take products with 120v/60Hz line xfrs and run them
in Europe 240V/50Hz with a step-down transformer. They would
saturate, overheat & pop fuses.

73, Josh W6XU

Sent from my mobile device


On Jul 6, 2022, at 12:51 PM, Dick Bingham 
wrote:

Greetings everyone

I hesitate to use my KPA-500 here at this CN98pi QTH. LIne
frequency here varies daily between 58.xx-to-61.yy Hz


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Re: [Elecraft] KPA-500 Line-Voltage Issues

[Fred Jensen]

and, though not always well known, ferrite cores in transformers for 
feeding antennas can also saturate with excess RF power.  The resulting 
RF din can be discouraging to neighbor hams and folks watching TV.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

Josh Fiden wrote on 7/6/2022 3:01 PM:

Transformer core can saturate if line frequency is too low. Except I’d be 
certain KPA-500 uses the same transformer for export to 50Hz countries so your 
variations are fine.

Many years ago when I was young & dumb discovered this the hard way. Customers 
would take products with 120v/60Hz line xfrs and run them in Europe 240V/50Hz with a 
step-down transformer. They would saturate, overheat & pop fuses.

73,
Josh W6XU

Sent from my mobile device






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Re: [Elecraft] KPA-500 Line-Voltage Issues

[Josh Fiden]

Transformer core can saturate if line frequency is too low. Except I’d be 
certain KPA-500 uses the same transformer for export to 50Hz countries so your 
variations are fine. 

Many years ago when I was young & dumb discovered this the hard way. Customers 
would take products with 120v/60Hz line xfrs and run them in Europe 240V/50Hz 
with a step-down transformer. They would saturate, overheat & pop fuses. 

73,
Josh W6XU 

Sent from my mobile device

> On Jul 6, 2022, at 12:51 PM, Dick Bingham  wrote:
> 
> Greetings everyone
> 
> I hesitate to use my KPA-500 here at this CN98pi QTH. LIne frequency here
> varies daily between 58.xx-to-61.yy Hz

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[Elecraft] KPA-500 Line-Voltage Issues

[Dick Bingham]

Greetings everyone

I hesitate to use my KPA-500 here at this CN98pi QTH. LIne frequency here
varies daily between 58.xx-to-61.yy Hz and line voltages vary between
110-to-130VAC due to the limitations of the governor controlling the
communities 200KW hydro system (Chelan County PUD remote facility).

When the refrigerator motor 'groans' I know the line frequency is
approaching 58-plus Hz and the system may crash if the auxiliary 75KW
diesel generator is too slow to pickup an instantaneous heavy load !!

I do NOT want to chance destroying my KPA-500 here, so only use it when at
CN97uj where line frequency variations amount to +/- 0.001Hz as displayed
in the PUD's main control room !

73  Dick/w7wkr
===
Message: 16
Date: Wed, 6 Jul 2022 12:53:12 +
From: Andy Durbin 
To: "elecraft@mailman.qth.net" 
Subject: [Elecraft] KPA500 Voltage range?
Message-ID:
<
co3pr13mb57363eeb535b89c6bc1e203d8c...@co3pr13mb5736.namprd13.prod.outlook.com
>

Content-Type: text/plain; charset="iso-8859-1"

"My kpa500 has the taps set to provide 71-72 VDC no load and drops to 60 at
500 watts."

Do you know how your house line input voltage varies?   Mine can be as high
as 122 and as low as 118 and the local transformer is less than 50 ft from
my house.

 I see unloaded KPA500 voltage over 80 with tap selected to keep loaded
KPA500 voltage at or above 60.   If your loaded voltage does not drop below
60 for all bands, all antenna loads, and all used output powers, I see no
reason to change the tap.  Band, loading, and power output all have a very
significant influence on efficiency, PA current, and voltage drop in the PA
HV supply.

Spot check values:
Line voltage 122.0
Unloaded HV 81.4
TX 500 W, 6 m band, SWR 1.15, HV 60.3

Andy, k3wyc
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Re: [Elecraft] KPA 500

[Jack Brindle via Elecraft]

With all the various pieces of information in this discussion, let’s answer 
things correctly. First, is hardwired cabling needed?
The answer is no, it is definitely not. The KPA500 always counts the RF 
frequency and will switch to the counted band if
it does not agree with whatever else it sees. If the input frequency from a 
cable says 10 meters, but the counted frequency is for 15 meters,
the amplifier _will_ switch to 15 meters. This is to make sure that we are 
always on the band for which RF iS coming in.
So, is there any advantage to having the hard-wired cable? Yes, a slight one. 
To answer this, let me explain how the band switching occurs.
When the amplifier detects, and confirms that RF is coming into the input port 
on a band different than what it was last using, it will 
institute a band change. This causes the KPA to drop out of amplifying, then 
switch bands, and then re-enable amplification.
This takes 17 milliseconds to accomplish. What this means is that you will lose 
a portion of the first CW character. If you were sending
a W, you will get a shortened dit. If you were sending at high speed, you might 
end up with an M. Considering that this happens
rarely (just on band changes), you probably won’t object to the shortened dit 
(or dah). Note that the count is always verified (at least
two valid counts must match as I recall).

So, what is the recommended usage? As I note, it works with a cable, or 
without. You just need the PTT input connected to the transceiver
so that the KPA knows when to go into transmit. Can there be problems with not 
using a frequency cable? The KPA does a remarkable job of 
protecting itself. You don’t want to make a habit of transmitting into the 
amplifier at 100 watts, or you could damage the front end protection.
But, in general it works just fine without problems.

So, what do _I_ use? I have the very first KPA, and another that is a couple of 
years old. I use a K3-compatible band cable with my amplifiers.
The biggest reason is that I am constantly testing my amplifiers (even while 
using them in a contest), and want to make sure everything is
working just fine. After more than ten years, no problems. I do test them 
without the cable at times as well.In general, when you hear me in a
contest, it is with the cables in use.

Thus, both ways work great. If you try it without a band cable and are troubled 
by the shortened dit, then build (or buy) a cable. Otherwise,
just enjoy the KPA500. We worked very hard on the protection circuits and 
processor code, and it does a very good job of taking care of itself.

73,
Jack, W6FB



> On Mar 22, 2022, at 4:24 AM, F5vjc  wrote:
> 
> What is the advantage of using a band switching cable between the
> transceiver and the KPA500 over just relying on the RF sensing function?
> 
> I want to drive my KPA500 from an FTDX 101D, is a cable the better way to
> go?
> 
> 73 F5VJC
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Re: [Elecraft] KPA 500

[N2TK, Tony via Elecraft]

Ken
You got me thinking. With my pair of K3’s and KPA500 and 1500 I can’t remember 
the last time I used a rig or amp to select a band. I usually use a logging or 
contesting program to click on a callout or type in a freq.
N2TK, Tony

Sent from my iPhone

> On Mar 23, 2022, at 5:00 PM, Ken K6MR  wrote:
> 
>  "They are a "bandaid" for the lack of band buttons on the K3."
> 
> I've always considered "band buttons" on any radio to be the worst possible 
> use of front panel space I can think of.  I always operate with a logging 
> program open, and it's far easier to just type in the frequency I want 
> without removing my hands from the keyboard.
> 
> I think with the amplifier they just had so much front panel space available 
> that they just couldn't think of anything else to put there.  In the years 
> I've had KPA500s and a KPA1500 I have yet to touch them.  To each his own.
> 
> Ken K6MR
> 
> 
> From: elecraft-boun...@mailman.qth.net  on 
> behalf of Andy Durbin 
> Sent: Wednesday, March 23, 2022 1:18 PM
> To: elecraft@mailman.qth.net 
> Subject: [Elecraft] KPA 500
> 
> "It’s also worth mentioning that if the radio and the amp are hard wired 
> together, changing the band using the buttons on the front of the amp 
> automatically changes the band on the radio."
> 
> It should be possible to disable the KPA 500 band buttons but it isn't.  They 
> are a "bandaid" for the lack of band buttons on the K3.  The best I could do 
> was set the KPA 500 back to TS-590 TX frequency in under 1 second if a KPA 
> 500 band button was accidentally pressed.
> 
> 0:06:08.474  New KPA_band  - ^BN03;
> 0:06:08.590  Sending ^BN08; to KPA500
> 0:06:08.975  New KPA_band  - ^BN08;
> 
> 
> Andy, k3wyc
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Re: [Elecraft] KPA 500

[Dr. William J. Schmidt]

During field day, I've seen unwanted leakage change the band on the amp from 
another transmitter during the receiving cycle.  Another good reason to 
hard-wire it.

email:  b...@wjschmidt.com


-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Wes
Sent: Wednesday, March 23, 2022 4:26 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA 500

Hmm.  I used to joke that I bought a KPA500 just so I could switch bands on my
K3 without accidentally changing the VOX setting.

N7WS

On 3/23/2022 1:58 PM, Ken K6MR wrote:
>   "They are a "bandaid" for the lack of band buttons on the K3."
>
> I've always considered "band buttons" on any radio to be the worst possible 
> use of front panel space I can think of.  I always operate with a logging 
> program open, and it's far easier to just type in the frequency I want 
> without removing my hands from the keyboard.
>
> I think with the amplifier they just had so much front panel space available 
> that they just couldn't think of anything else to put there.  In the years 
> I've had KPA500s and a KPA1500 I have yet to touch them.  To each his own.
>
> Ken K6MR
>
>

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Re: [Elecraft] KPA 500

[Wes]

Hmm.  I used to joke that I bought a KPA500 just so I could switch bands on my 
K3 without accidentally changing the VOX setting.


N7WS

On 3/23/2022 1:58 PM, Ken K6MR wrote:

  "They are a "bandaid" for the lack of band buttons on the K3."

I've always considered "band buttons" on any radio to be the worst possible use 
of front panel space I can think of.  I always operate with a logging program open, and 
it's far easier to just type in the frequency I want without removing my hands from the 
keyboard.

I think with the amplifier they just had so much front panel space available 
that they just couldn't think of anything else to put there.  In the years I've 
had KPA500s and a KPA1500 I have yet to touch them.  To each his own.

Ken K6MR




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Re: [Elecraft] KPA 500

[Ken K6MR]

 "They are a "bandaid" for the lack of band buttons on the K3."

I've always considered "band buttons" on any radio to be the worst possible use 
of front panel space I can think of.  I always operate with a logging program 
open, and it's far easier to just type in the frequency I want without removing 
my hands from the keyboard.

I think with the amplifier they just had so much front panel space available 
that they just couldn't think of anything else to put there.  In the years I've 
had KPA500s and a KPA1500 I have yet to touch them.  To each his own.

Ken K6MR


From: elecraft-boun...@mailman.qth.net  on 
behalf of Andy Durbin 
Sent: Wednesday, March 23, 2022 1:18 PM
To: elecraft@mailman.qth.net 
Subject: [Elecraft] KPA 500

"It’s also worth mentioning that if the radio and the amp are hard wired 
together, changing the band using the buttons on the front of the amp 
automatically changes the band on the radio."

It should be possible to disable the KPA 500 band buttons but it isn't.  They 
are a "bandaid" for the lack of band buttons on the K3.  The best I could do 
was set the KPA 500 back to TS-590 TX frequency in under 1 second if a KPA 500 
band button was accidentally pressed.

 0:06:08.474  New KPA_band  - ^BN03;
 0:06:08.590  Sending ^BN08; to KPA500
 0:06:08.975  New KPA_band  - ^BN08;


Andy, k3wyc
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[Elecraft] KPA 500

[Andy Durbin]

"It’s also worth mentioning that if the radio and the amp are hard wired 
together, changing the band using the buttons on the front of the amp 
automatically changes the band on the radio."

It should be possible to disable the KPA 500 band buttons but it isn't.  They 
are a "bandaid" for the lack of band buttons on the K3.  The best I could do 
was set the KPA 500 back to TS-590 TX frequency in under 1 second if a KPA 500 
band button was accidentally pressed.

 0:06:08.474  New KPA_band  - ^BN03;
 0:06:08.590  Sending ^BN08; to KPA500
 0:06:08.975  New KPA_band  - ^BN08;


Andy, k3wyc
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Re: [Elecraft] KPA 500

[Richard]

It’s also worth mentioning that if the radio and the amp are hard wired 
together, changing the band using the buttons on the front of the amp 
automatically changes the band on the radio.

Richard
W4KBX

> With the  band switching cable between the radio and amp, the amp follows the 
> receiver frequency/band.  Thus it is not necessary key the radio or to 
> transmit anything.
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[Elecraft] KPA 500

[Bob McGraw]

With the  band switching cable between the radio and amp, the amp 
follows the receiver frequency/band.  Thus it is not necessary key the 
radio or to transmit anything.  The bands are loaded with miscellaneous 
garbage today.  Why add any more?


My K3S connects to my KAT500 which connects to my KPA500.   Sure is a 
sweet and reliable system.  Hard to screw up anything.


73

Bob, K4TAX


On 3/23/2022 2:14 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 6
Date: Tue, 22 Mar 2022 10:24:59 +0100
From: F5vjc
To: Elecraft Reflector
Subject: [Elecraft] KPA 500
Message-ID:

Content-Type: text/plain; charset="UTF-8"

What is the advantage of using a band switching cable between the
transceiver and the KPA500 over just relying on the RF sensing function?

I want to drive my KPA500 from an FTDX 101D, is a cable the better way to
go?

73 F5VJC


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Re: [Elecraft] KPA 500

[Wes]

Although I have a K3 and a K3S, they are relegated to backup service to my 
Kenwood TS-890.


A number of us Kenwood users also have KPA500 and KAT500s.  We are using mostly 
home-built cables for interconnection.  If you don't have the KAT500 then RF 
sensing is probably good enough.  The advantage to the cable when the KAT500 is 
employed is that it can be preset to the band and tuning solution, when the 
transceiver changes frequency, without transmitting.  This is particularly handy 
when just listening.


Wes  N7WS

On 3/22/2022 11:31 AM, j...@kk9a.com wrote:

A long time ago I used a KPA500 with a Yaesu FT1000MP and the RF sensing
worked perfectly. Perhaps if you have a KAT500 and are using different
antenna ports or have very out of tune antennas there may be an advantage to
having cable control but otherwise I would not worry about it.

John KK9A



F5vjc wrote:


transceiver and the KPA500 over just relying on the RF sensing function?

I want to drive my KPA500 from an FTDX 101D, is a cable the better way to
go?

73 F5VJC

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Re: [Elecraft] KPA 500

[john]

A long time ago I used a KPA500 with a Yaesu FT1000MP and the RF sensing
worked perfectly. Perhaps if you have a KAT500 and are using different
antenna ports or have very out of tune antennas there may be an advantage to
having cable control but otherwise I would not worry about it.

John KK9A



F5vjc wrote:


transceiver and the KPA500 over just relying on the RF sensing function?

I want to drive my KPA500 from an FTDX 101D, is a cable the better way to
go?

73 F5VJC

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Re: [Elecraft] KPA 500

[Jim Brown]

On 3/22/2022 2:24 AM, F5vjc wrote:

What is the advantage of using a band switching cable between the
transceiver and the KPA500 over just relying on the RF sensing function?


I've never used one. A tap on the mic or a dit is all that is needed.

73, Jim K9YC
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Re: [Elecraft] KPA 500

[jerry]

On 2022-03-22 02:24, F5vjc wrote:

What is the advantage of using a band switching cable between the
transceiver and the KPA500 over just relying on the RF sensing 
function?




Do you trust that RF sensing function?  REALLY trust it?  Because if you 
transmit
into the wrong LPF, it can be Game Over for the PA transistors.  I went 
through
three sets of expensive LDMOS devices on my Medium Linear project before 
I bit the bullet

and hooked up the band data from my FTDX10.

With the band data hooked up, the linear is always set to the correct 
band.  Even before

you transmit.

  - Jerry KF6VB








I want to drive my KPA500 from an FTDX 101D, is a cable the better way 
to

go?

73 F5VJC
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[Elecraft] KPA 500

[F5vjc]

What is the advantage of using a band switching cable between the
transceiver and the KPA500 over just relying on the RF sensing function?

I want to drive my KPA500 from an FTDX 101D, is a cable the better way to
go?

73 F5VJC
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[Elecraft] KPA 500

[John Pierce via Elecraft]

The unit was sold.

 

AD2F

John

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[Elecraft] KPA 500

[John Pierce via Elecraft]

Unit was sold

 

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Re: [Elecraft] KPA 500 for Sale

[Julia Tuttle]

Do you have a price in mind?

On Tue, Oct 19, 2021, 16:47 John Pierce via Elecraft <
elecraft@mailman.qth.net> wrote:

> Excellent Condition, light usage.
>
>
>
> AD2F
>
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[Elecraft] KPA 500 for Sale

[John Pierce via Elecraft]

Excellent Condition, light usage.

 

AD2F

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[Elecraft] KPA 500 for Sale

[John Pierce via Elecraft]

I have my KPA500 for sale.  My location is NJ

 

John, AD2F

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[Elecraft] KPA-500 for sale, excellent condition

[John Harper]

Local buyer (SETX) preferred:

https://ae5x.blogspot.com/2021/09/elecraft-kpa-500-for-sale-local-buyer.html

73,
John AE5X
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Re: [Elecraft] KPA-500 270V ERR

[David Gilbert]

Well, at the risk of offending Fred ...

A PIN diode has an intrinsic (I) region between the P and N junctions.  
The I region is almost completely undoped and therefore the carrier 
lifetimes are long relative to the frequency of the signal being 
switched.  A PIN diode is turned on with CURRENT bias, and as long as 
the signal current is less than the bias current the carriers live long 
enough in the I region that the signal just swishes the carriers back 
and forth without the diode ever becoming reverse biased ... and that 
holds pretty much no matter what the signal peak to peak voltage is.  
You turn off a PIN by removing the bias current ... or better yet, 
reversing it to pull out the carriers.  The hard part of making a normal 
PIN diode is that you have to start with an intrinsic wafer and then 
diffuse first from one side and then the other side ... and while you're 
diffusing the second side the dopant from the first side wants to 
contaminate the I region.  (There are other techniques but they get even 
weirder).


A PN diode, on the other hand, is forward biased (i.e., "on") as long as 
the control VOLTAGE exceeds the signal voltage.  As soon as the voltage 
across the diode reverses, mobile carriers are soon swept out of the 
junction area and the diode becomes reverse biased and shuts off.  As 
you say, that reverse bias could from either the control voltage OR a 
higher than expected signal voltage if the reverse peaks of the signal 
voltage exceed the control voltage. How fast all of that that happens 
depends upon the carrier lifetimes in the junction region and the 
frequency of the signal being switched.  Fast switching diodes are built 
with high doping levels to give a narrow junction and short carrier 
lifetimes, but some high voltage diodes have low doping levels, wide 
junctions, and therefore moderately slow carrier recombination times.  
If it just happens that the carrier lifetimes are long enough compared 
to the signal frequency, it can work.  However, I think it's generally 
bad practice to use a standard diode as a PIN because unexpectedly high 
signal voltages can reverse bias the diode and create signal distortion 
... plus the fact that diode manufacturers are NOT designing standard 
diodes for use as a PIN diode, and they are NOT specifically trying to 
control carrier lifetimes during fabrication.  A pair of high voltage 
switching diodes can both fully meet the data sheet specs, while one 
works quite a bit better than the other when used as a PIN.  That which 
works with today's batch might not work with tomorrow's.


73,
Dave   AB7E


On 8/26/2021 3:58 PM, jerry wrote:

On 2021-08-26 15:19, David Gilbert wrote:

Pedantic?  If those were truly PIN diodes like you called them the
270v bias wouldn't have been used there.



Actually, I'm finding this interesting.  So with real PIN diodes, you 
don't have

to strongly bias them off?

The HV is obtained in various ways.  W6JL does diode switching with a 
tube amp, so he has ample HV available.  My K2 has a crystal 
oscillator feeding a toroid transformer and a voltage multiplier.  
Hans Summers uses a voltage doubler running off the RF output of his 
amplifier.  I have heard discussions of people

using fluorescent ballast transformers.

A complication is that the voltage at a transmitter output - even 
though it's nominal 50 ohms - can rise quite high with high SWR, 
especially in the "looks like an open circuit" direction.  So even 
though modern LDMOS PA transistors are rated to tolerate extremely 
high SWRs, your equipment is limited to the SWR that produces a 
voltage lower than the diode bias.  Hans Summers' design is elegant - 
since he's rectifying and multiplying the RF itself, the DC is 
guaranteed to be higher than the RF itself.  Only thing is - there is 
surely a delay in creating that bias.


  I will say that the QRP-labs approach somehow results in the 
cleanest, most transparent-sounding QSK I've ever heard.  Better than 
my K2.  But it's only one band, the selectivity is just ok, and it has 
no AGC...


    - Jerry KF6VB





Dave   AB7E


On 8/26/2021 2:56 PM, Fred Jensen wrote:
This morphed into a pedantic discussion of solid state diodes.  
Chuck's original question was about the 270 V error.  I'm fairly 
sure the only purpose for the 270 V in a KPA500 is bias for the T-R 
switch.  He asked for suggestions.  The T-R switch and the source 
for the 270 V might be a good place to start troubleshooting.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 2:23 PM, David Gilbert wrote:


High voltage rectifier diodes would have very low doped N-regions, 
which means fairly long carrier lifetimes so no doubt they work 
somewhat like a PIN diode if properly biased.  But they aren't 
really the same thing, and I still say that a PIN diode has 
performance advantages in many situations.  They are more difficult 
and costly to build, though.


I used to manage a large 

Re: [Elecraft] KPA-500 270V ERR

[jerry]

On 2021-08-26 15:19, David Gilbert wrote:

Pedantic?  If those were truly PIN diodes like you called them the
270v bias wouldn't have been used there.



Actually, I'm finding this interesting.  So with real PIN diodes, you 
don't have

to strongly bias them off?

The HV is obtained in various ways.  W6JL does diode switching with a 
tube amp, so he has ample HV available.  My K2 has a crystal oscillator 
feeding a toroid transformer and a voltage multiplier.  Hans Summers 
uses a voltage doubler running off the RF output of his amplifier.  I 
have heard discussions of people

using fluorescent ballast transformers.

A complication is that the voltage at a transmitter output - even though 
it's nominal 50 ohms - can rise quite high with high SWR, especially in 
the "looks like an open circuit" direction.  So even though modern LDMOS 
PA transistors are rated to tolerate extremely high SWRs, your equipment 
is limited to the SWR that produces a voltage lower than the diode bias. 
 Hans Summers' design is elegant - since he's rectifying and multiplying 
the RF itself, the DC is guaranteed to be higher than the RF itself.  
Only thing is - there is surely a delay in creating that bias.


  I will say that the QRP-labs approach somehow results in the cleanest, 
most transparent-sounding QSK I've ever heard.  Better than my K2.  But 
it's only one band, the selectivity is just ok, and it has no AGC...


- Jerry KF6VB





Dave   AB7E


On 8/26/2021 2:56 PM, Fred Jensen wrote:
This morphed into a pedantic discussion of solid state diodes.  
Chuck's original question was about the 270 V error.  I'm fairly sure 
the only purpose for the 270 V in a KPA500 is bias for the T-R 
switch.  He asked for suggestions.  The T-R switch and the source for 
the 270 V might be a good place to start troubleshooting.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 2:23 PM, David Gilbert wrote:


High voltage rectifier diodes would have very low doped N-regions, 
which means fairly long carrier lifetimes so no doubt they work 
somewhat like a PIN diode if properly biased.  But they aren't really 
the same thing, and I still say that a PIN diode has performance 
advantages in many situations.  They are more difficult and costly to 
build, though.


I used to manage a large semiconductor entity that manufactured these 
things.


73,
Dave   AB7E

On 8/26/2021 2:05 PM, jerry wrote:
Using 1N4007's and 1N5208's ( I could have the last # wrong ) as 
"Poor Man PIN
diodes" is pretty established practice in the amateur community. 
Look up
W6JL on QRZ.com.  He has an extensive article about it on his page 
there.


Also Hans Summers of qrp-labs uses them in his 50W QSK amplifier.

  Apparently, these kilovolt rectifiers behave very much like PIN 
diodes,

at speed.

   - Jerry KF6VB

On 2021-08-26 11:46, David Gilbert wrote:
That sounds odd to me.  True PIN diodes are current actuated 
devices.
The carrier lifetimes are long enough that the devices are "on" 
even
if the signal peaks exceed the voltage of the control current ... 
as

long, of course, as the control current exceeds the signal current.

On the other hand, I've heard that Elecraft has sometimes used 
regular

switching diodes instead of PINs, and for those you need a voltage
that exceeds the peak voltage of whatever you're switching.

Both types of diodes have their place ... using one where the other
works better is not good practice.

73,
Dave   AB7E

On 8/26/2021 11:33 AM, Fred Jensen wrote:
I think the 270 V circuit is DC bias for the PIN diodes in the 
TR-switch.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it
was making the occasional extra "click" or "thunk" upon powering 
up or
down.  Usually it would "click" when powered up and again when 
powered
down, but recently a few seconds after the first click there 
would be

another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the 
Operate/Standby button
I got a fault light and the 270V ERR message on the display. The 
menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on 
the bench
and opened up the top cover.  There is a smell of overheated 
components,

maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L


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Re: [Elecraft] KPA-500 270V ERR

[David Gilbert]

Pedantic?  If those were truly PIN diodes like you called them the 270v 
bias wouldn't have been used there.


Dave   AB7E


On 8/26/2021 2:56 PM, Fred Jensen wrote:
This morphed into a pedantic discussion of solid state diodes.  
Chuck's original question was about the 270 V error.  I'm fairly sure 
the only purpose for the 270 V in a KPA500 is bias for the T-R 
switch.  He asked for suggestions.  The T-R switch and the source for 
the 270 V might be a good place to start troubleshooting.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 2:23 PM, David Gilbert wrote:


High voltage rectifier diodes would have very low doped N-regions, 
which means fairly long carrier lifetimes so no doubt they work 
somewhat like a PIN diode if properly biased.  But they aren't really 
the same thing, and I still say that a PIN diode has performance 
advantages in many situations.  They are more difficult and costly to 
build, though.


I used to manage a large semiconductor entity that manufactured these 
things.


73,
Dave   AB7E

On 8/26/2021 2:05 PM, jerry wrote:
Using 1N4007's and 1N5208's ( I could have the last # wrong ) as 
"Poor Man PIN
diodes" is pretty established practice in the amateur community. 
Look up
W6JL on QRZ.com.  He has an extensive article about it on his page 
there.


Also Hans Summers of qrp-labs uses them in his 50W QSK amplifier.

  Apparently, these kilovolt rectifiers behave very much like PIN 
diodes,

at speed.

   - Jerry KF6VB

On 2021-08-26 11:46, David Gilbert wrote:

That sounds odd to me.  True PIN diodes are current actuated devices.
The carrier lifetimes are long enough that the devices are "on" even
if the signal peaks exceed the voltage of the control current ... as
long, of course, as the control current exceeds the signal current.

On the other hand, I've heard that Elecraft has sometimes used regular
switching diodes instead of PINs, and for those you need a voltage
that exceeds the peak voltage of whatever you're switching.

Both types of diodes have their place ... using one where the other
works better is not good practice.

73,
Dave   AB7E

On 8/26/2021 11:33 AM, Fred Jensen wrote:
I think the 270 V circuit is DC bias for the PIN diodes in the 
TR-switch.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it
was making the occasional extra "click" or "thunk" upon powering 
up or
down.  Usually it would "click" when powered up and again when 
powered
down, but recently a few seconds after the first click there 
would be

another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the 
Operate/Standby button
I got a fault light and the 270V ERR message on the display. The 
menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on 
the bench
and opened up the top cover.  There is a smell of overheated 
components,

maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L


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Re: [Elecraft] KPA-500 270V ERR

[Fred Jensen]

This morphed into a pedantic discussion of solid state diodes.  Chuck's 
original question was about the 270 V error.  I'm fairly sure the only 
purpose for the 270 V in a KPA500 is bias for the T-R switch.  He asked 
for suggestions.  The T-R switch and the source for the 270 V might be a 
good place to start troubleshooting.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 2:23 PM, David Gilbert wrote:


High voltage rectifier diodes would have very low doped N-regions, 
which means fairly long carrier lifetimes so no doubt they work 
somewhat like a PIN diode if properly biased.  But they aren't really 
the same thing, and I still say that a PIN diode has performance 
advantages in many situations.  They are more difficult and costly to 
build, though.


I used to manage a large semiconductor entity that manufactured these 
things.


73,
Dave   AB7E

On 8/26/2021 2:05 PM, jerry wrote:
Using 1N4007's and 1N5208's ( I could have the last # wrong ) as 
"Poor Man PIN

diodes" is pretty established practice in the amateur community. Look up
W6JL on QRZ.com.  He has an extensive article about it on his page 
there.


Also Hans Summers of qrp-labs uses them in his 50W QSK amplifier.

  Apparently, these kilovolt rectifiers behave very much like PIN 
diodes,

at speed.

   - Jerry KF6VB

On 2021-08-26 11:46, David Gilbert wrote:

That sounds odd to me.  True PIN diodes are current actuated devices.
The carrier lifetimes are long enough that the devices are "on" even
if the signal peaks exceed the voltage of the control current ... as
long, of course, as the control current exceeds the signal current.

On the other hand, I've heard that Elecraft has sometimes used regular
switching diodes instead of PINs, and for those you need a voltage
that exceeds the peak voltage of whatever you're switching.

Both types of diodes have their place ... using one where the other
works better is not good practice.

73,
Dave   AB7E

On 8/26/2021 11:33 AM, Fred Jensen wrote:
I think the 270 V circuit is DC bias for the PIN diodes in the 
TR-switch.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it
was making the occasional extra "click" or "thunk" upon powering 
up or
down.  Usually it would "click" when powered up and again when 
powered

down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the 
Operate/Standby button
I got a fault light and the 270V ERR message on the display. The 
menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on 
the bench
and opened up the top cover.  There is a smell of overheated 
components,

maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L


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Re: [Elecraft] KPA-500 270V ERR

[David Gilbert]

High voltage rectifier diodes would have very low doped N-regions, which 
means fairly long carrier lifetimes so no doubt they work somewhat like 
a PIN diode if properly biased.  But they aren't really the same thing, 
and I still say that a PIN diode has performance advantages in many 
situations.  They are more difficult and costly to build, though.


I used to manage a large semiconductor entity that manufactured these 
things.


73,
Dave   AB7E




On 8/26/2021 2:05 PM, jerry wrote:
Using 1N4007's and 1N5208's ( I could have the last # wrong ) as "Poor 
Man PIN

diodes" is pretty established practice in the amateur community. Look up
W6JL on QRZ.com.  He has an extensive article about it on his page there.

Also Hans Summers of qrp-labs uses them in his 50W QSK amplifier.

  Apparently, these kilovolt rectifiers behave very much like PIN diodes,
at speed.

   - Jerry KF6VB



On 2021-08-26 11:46, David Gilbert wrote:

That sounds odd to me.  True PIN diodes are current actuated devices.
The carrier lifetimes are long enough that the devices are "on" even
if the signal peaks exceed the voltage of the control current ... as
long, of course, as the control current exceeds the signal current.

On the other hand, I've heard that Elecraft has sometimes used regular
switching diodes instead of PINs, and for those you need a voltage
that exceeds the peak voltage of whatever you're switching.

Both types of diodes have their place ... using one where the other
works better is not good practice.

73,
Dave   AB7E



On 8/26/2021 11:33 AM, Fred Jensen wrote:
I think the 270 V circuit is DC bias for the PIN diodes in the 
TR-switch.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it

was making the occasional extra "click" or "thunk" upon powering up or
down.  Usually it would "click" when powered up and again when powered
down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the Operate/Standby 
button
I got a fault light and the 270V ERR message on the display. The 
menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on 
the bench
and opened up the top cover.  There is a smell of overheated 
components,

maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L




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Re: [Elecraft] KPA-500 270V ERR

[jerry]

Using 1N4007's and 1N5208's ( I could have the last # wrong ) as "Poor 
Man PIN
diodes" is pretty established practice in the amateur community.  Look 
up
W6JL on QRZ.com.  He has an extensive article about it on his page 
there.


Also Hans Summers of qrp-labs uses them in his 50W QSK amplifier.

  Apparently, these kilovolt rectifiers behave very much like PIN 
diodes,

at speed.

   - Jerry KF6VB



On 2021-08-26 11:46, David Gilbert wrote:

That sounds odd to me.  True PIN diodes are current actuated devices. 
The carrier lifetimes are long enough that the devices are "on" even
if the signal peaks exceed the voltage of the control current ... as
long, of course, as the control current exceeds the signal current.

On the other hand, I've heard that Elecraft has sometimes used regular
switching diodes instead of PINs, and for those you need a voltage
that exceeds the peak voltage of whatever you're switching.

Both types of diodes have their place ... using one where the other
works better is not good practice.

73,
Dave   AB7E



On 8/26/2021 11:33 AM, Fred Jensen wrote:
I think the 270 V circuit is DC bias for the PIN diodes in the 
TR-switch.


73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it
was making the occasional extra "click" or "thunk" upon powering up 
or
down.  Usually it would "click" when powered up and again when 
powered

down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the Operate/Standby 
button
I got a fault light and the 270V ERR message on the display. The menu 
HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on the 
bench
and opened up the top cover.  There is a smell of overheated 
components,

maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L




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Re: [Elecraft] KPA-500 270V ERR

[Andy Durbin]

My schematic shows TR Switch diode type is S1M.  Datasheet easily found on-line.

I doubt this has any influence of 270 V failure.

Andy, k3wyc

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Re: [Elecraft] KPA-500 270V ERR

[David Gilbert]

That sounds odd to me.  True PIN diodes are current actuated devices.  
The carrier lifetimes are long enough that the devices are "on" even if 
the signal peaks exceed the voltage of the control current ... as long, 
of course, as the control current exceeds the signal current.


On the other hand, I've heard that Elecraft has sometimes used regular 
switching diodes instead of PINs, and for those you need a voltage that 
exceeds the peak voltage of whatever you're switching.


Both types of diodes have their place ... using one where the other 
works better is not good practice.


73,
Dave   AB7E



On 8/26/2021 11:33 AM, Fred Jensen wrote:

I think the 270 V circuit is DC bias for the PIN diodes in the TR-switch.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:
My KPA-500 has been running great for several years.  Recently I 
noticed it

was making the occasional extra "click" or "thunk" upon powering up or
down.  Usually it would "click" when powered up and again when powered
down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the Operate/Standby 
button

I got a fault light and the 270V ERR message on the display. The menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on the 
bench

and opened up the top cover.  There is a smell of overheated components,
maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page. Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L




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Re: [Elecraft] KPA-500 270V ERR

[Fred Jensen]

I think the 270 V circuit is DC bias for the PIN diodes in the TR-switch.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 8/26/2021 10:32 AM, Chuck Chandler wrote:

My KPA-500 has been running great for several years.  Recently I noticed it
was making the occasional extra "click" or "thunk" upon powering up or
down.  Usually it would "click" when powered up and again when powered
down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the Operate/Standby button
I got a fault light and the 270V ERR message on the display.  The menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on the bench
and opened up the top cover.  There is a smell of overheated components,
maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page.  Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L




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[Elecraft] KPA-500 270V ERR

[Andy Durbin]

Well if it were mine I'd check the voltage on the nominal 270 V connector on 
the PA module then work back from there.

I keep notes from discussion of other peoples problems and their resolution.  
You can find all this in the archive but this is what I have in my notes for 
KPA 270 V problems:



KPA500 270V failure:
(two post by  Dr. William J. Schmidt  )

There are two voltage Test Points "TP" on the board under
with the diodes and  you need to check the voltages on those test points.

Here it is.  From Elecraft technical support:

Nominally:

TP2= RX 13.1 TX 0.8
TP4= RX 3.9 TX 13

>From Rene Morris at Elecraft (great guy!).


and

Thanks for the reply but in my case the problem is the voltage multiplier
circuit on the power supply PCB. I just disconnected the HV (~70V) and 270V
lines so they did not go anywhere and the 270V line still only measures 85V.

Thanks
Bruce, WB6IZG


Thanks to the 2 people who replied. Thanks to Keith VE7KW who had R16 (100
Ohm) SMD resistor fail on his PS board in his KPA500. I had the same
problem here. R16 tested open. It does not appear to be cracked or burnt,
just a failure. R16 appears to be a resistor that feeds the voltage
multiplier circuit for the 270V line.

Bottom line is my KPA500 is back in service.

Bruce, WB6IZG



Good luck and let us know what you find.

73,
Andy, k3wyc
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[Elecraft] KPA-500 270V ERR

[Chuck Chandler]

My KPA-500 has been running great for several years.  Recently I noticed it
was making the occasional extra "click" or "thunk" upon powering up or
down.  Usually it would "click" when powered up and again when powered
down, but recently a few seconds after the first click there would be
another one, maybe more of a thunk sound.

This afternoon I turned it on and when I pushed the Operate/Standby button
I got a fault light and the 270V ERR message on the display.  The menu HV
option shows 68.4V, varying a bit, on my 240V line.  I put it on the bench
and opened up the top cover.  There is a smell of overheated components,
maybe burnt but more like too hot.

I've submitted the contact form on the Elecraft support page.  Any
suggestions?  For now, I'm running barefoot...

73 de Chuck, WS1L

chandler...@gmail.com
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[Elecraft] KPA-500 Warm

[Bob McGraw]

See page 14, paragraph 1. for the confirmation of why the left rear 
corner is warm.


73

Bob, K4TAX


On 6/30/2021 7:12 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 2
Date: Wed, 30 Jun 2021 09:08:41 -0700
From: Phil Hystad
To: Ken Winterling
Cc: Elecraft Reflector
Subject: Re: [Elecraft] Temperature or Warmth of KPA500 when "Off" ?
Message-ID:<50e8c4c6-72af-4261-a950-295a3731c...@mac.com>
Content-Type: text/plain;   charset=utf-8

Yes, there is a master switch.  I think I forgot about that.


On Jun 30, 2021, at 8:47 AM, Ken Winterling  wrote:

Phil,

No need to unplug the KPA500 when not in use. There is a master power
switch on the rear panel that will disconnect everything.

Ken
WA2LBI

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[Elecraft] KPA 500

[Ezra Carmel via Elecraft]

Hello.

During operation with a high SWR and low power I heard a strong bang and the
KPA500 shut off.

I have opened the upper panel and found  2 ceramic caps of VRF2933. The
inner side of the plastic cover is blackened

Looks that the power supply is working I read 74.6 volt on the voltage
display on the LCD.

Have written to support  but did not receive any answer.

Is it enough to replace the 2 X VRF2933.

Is someone aware  of a procedure of reaching the finals?

 

73

Ezra Carmel

4Z4RQ

ISRAEL

  

 

 

 

 

 

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[Elecraft] KPA-500 and KAT-500 For Sale

[Doug Eaton via Elecraft]

For Sale: KPA-500-K serial #29XX in excellent condition.original owner and 
non-smoking home.Amp is in good working condition. No scratches, scuffs or 
other cosmetic flaws.$1695 plus shipping and insurance.
Also For Sale: KAT-500-F antenna tuner serial #19XX.In excellent condition 
cosmetically and electrically.$475.00 shipped to lower 48 states.Extra cost for 
shipping to other areas.
n...@yahoo.com
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[Elecraft] KPA 500

[Pete Block]

I recently say a listing for a used KPA500. I managed to lose the info. If
it's still availably could you please let me have the info. I'm very
interested.

Pete Block

W2MGE

pete_bl...@comcast.net  

Thanks.

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Re: [Elecraft] KPA 500 Codan Envoy

[Bill Steffey NY9H]

maybe the real questions are will the KPA500 work withan ALE 
requirement


Band jumping and other cool stuff are essential for  ALE.

On 6/29/2020 11:52 AM, Mark Goldberg wrote:

I think as a Ham, you can use anything you want on the Ham bands. As a
manufacturer to sell it, it may need type acceptance for the service
it is intended to be used in.

Lots of people use aviation HF rigs on the Ham bands and you can use
an amp that works on 11M or with more than the allowable gain. A
manufacturer can't sell that for use in the Ham bands, but an
individual Ham can use anything as long as it is operated within the
regulations. I know a friend that has a huge amplifier capable of
maybe 10kW. He got a visit from the FCC (long ago, don't think they
care now). He showed them how it was correctly operated within the
regs and how he had the ability to measure it and assure it was. The
FCC guy wished him a good day.

Other services where the operator is not technical and has not passed
a technical exam require radios type accepted for that service as I
understand things.

73,

Mark
W7MLG

On Mon, Jun 29, 2020 at 7:47 AM Lyn Norstad  wrote:

Maybe Bob wants to use the Envoy 2 on the ham bands.  I'm not familiar with
the Codan line of military/business transceivers, but I see that model does
have transmit coverage from 1.6 to 30 MHz.

Perhaps the real question is whether it would be legal to use that rig on
the ham bands.  Since it can apparently cover the 160 - 10m bands without
modification, wouldn't it need to be type accepted?

73
Lyn, W0LEN


-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Mark Goldberg
Sent: Monday, June 29, 2020 9:09 AM
To: Bob Morgan
Cc: Elecraft Mailing List
Subject: Re: [Elecraft] KPA 500 Codan Envoy

That is not a Ham radio. Is it legal to use an amplifier type accepted
for Ham radio for other services?

73,

Mark
W7MLG


On Mon, Jun 29, 2020 at 6:49 AM Bob Morgan  wrote:

I would like to know if any in the group has used the KPA 500 with a Codan
Envoy 2. Any help would be much appreciated.
Bob Morgan
KJ4SV
865 207 9568



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This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

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Re: [Elecraft] KPA 500 Codan Envoy

[Charlie T]

" Perhaps the real question is whether it would be legal to use that rig on
the ham bands.  Since it can apparently cover the 160 - 10m bands without
modification, wouldn't it need to be type accepted?"


Only if the company's intention was to sell specifically to the HAM
community.

They of course, have the OK for their existing market.

Also, any licensed ham could use this radio if it was obtained on the "used"
market.
If this were NOT legal, we could therefore, not use commercial  an old BC
transmitter for legal limit AM.
Or, for that matter ANY radio not designated for HAM use.obviously, NOT
the case.

73, Charlie k3ICH




-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Lyn Norstad
Sent: Monday, June 29, 2020 10:47 AM
To: 'Mark Goldberg' ; 'Bob Morgan'

Cc: 'Elecraft Mailing List' 
Subject: Re: [Elecraft] KPA 500 Codan Envoy

Maybe Bob wants to use the Envoy 2 on the ham bands.  I'm not familiar with
the Codan line of military/business transceivers, but I see that model does
have transmit coverage from 1.6 to 30 MHz.

Perhaps the real question is whether it would be legal to use that rig on
the ham bands.  Since it can apparently cover the 160 - 10m bands without
modification, wouldn't it need to be type accepted?

73
Lyn, W0LEN
 

 

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Re: [Elecraft] KPA 500 Codan Envoy

[Mark Goldberg]

I think as a Ham, you can use anything you want on the Ham bands. As a
manufacturer to sell it, it may need type acceptance for the service
it is intended to be used in.

Lots of people use aviation HF rigs on the Ham bands and you can use
an amp that works on 11M or with more than the allowable gain. A
manufacturer can't sell that for use in the Ham bands, but an
individual Ham can use anything as long as it is operated within the
regulations. I know a friend that has a huge amplifier capable of
maybe 10kW. He got a visit from the FCC (long ago, don't think they
care now). He showed them how it was correctly operated within the
regs and how he had the ability to measure it and assure it was. The
FCC guy wished him a good day.

Other services where the operator is not technical and has not passed
a technical exam require radios type accepted for that service as I
understand things.

73,

Mark
W7MLG

On Mon, Jun 29, 2020 at 7:47 AM Lyn Norstad  wrote:
>
> Maybe Bob wants to use the Envoy 2 on the ham bands.  I'm not familiar with
> the Codan line of military/business transceivers, but I see that model does
> have transmit coverage from 1.6 to 30 MHz.
>
> Perhaps the real question is whether it would be legal to use that rig on
> the ham bands.  Since it can apparently cover the 160 - 10m bands without
> modification, wouldn't it need to be type accepted?
>
> 73
> Lyn, W0LEN
>
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net
> [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Mark Goldberg
> Sent: Monday, June 29, 2020 9:09 AM
> To: Bob Morgan
> Cc: Elecraft Mailing List
> Subject: Re: [Elecraft] KPA 500 Codan Envoy
>
> That is not a Ham radio. Is it legal to use an amplifier type accepted
> for Ham radio for other services?
>
> 73,
>
> Mark
> W7MLG
>
>
> On Mon, Jun 29, 2020 at 6:49 AM Bob Morgan  wrote:
> >
> > I would like to know if any in the group has used the KPA 500 with a Codan
> > Envoy 2. Any help would be much appreciated.
> > Bob Morgan
> > KJ4SV
> > 865 207 9568
> >
> >
> >
> > --
> > Sent from: http://elecraft.365791.n2.nabble.com/
> > __
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Re: [Elecraft] KPA 500 Codan Envoy

[Lyn Norstad]

Maybe Bob wants to use the Envoy 2 on the ham bands.  I'm not familiar with
the Codan line of military/business transceivers, but I see that model does
have transmit coverage from 1.6 to 30 MHz.

Perhaps the real question is whether it would be legal to use that rig on
the ham bands.  Since it can apparently cover the 160 - 10m bands without
modification, wouldn't it need to be type accepted?

73
Lyn, W0LEN
 

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Mark Goldberg
Sent: Monday, June 29, 2020 9:09 AM
To: Bob Morgan
Cc: Elecraft Mailing List
Subject: Re: [Elecraft] KPA 500 Codan Envoy

That is not a Ham radio. Is it legal to use an amplifier type accepted
for Ham radio for other services?

73,

Mark
W7MLG


On Mon, Jun 29, 2020 at 6:49 AM Bob Morgan  wrote:
>
> I would like to know if any in the group has used the KPA 500 with a Codan
> Envoy 2. Any help would be much appreciated.
> Bob Morgan
> KJ4SV
> 865 207 9568
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> __
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Re: [Elecraft] KPA 500 Codan Envoy

[Mark Goldberg]

That is not a Ham radio. Is it legal to use an amplifier type accepted
for Ham radio for other services?

73,

Mark
W7MLG


On Mon, Jun 29, 2020 at 6:49 AM Bob Morgan  wrote:
>
> I would like to know if any in the group has used the KPA 500 with a Codan
> Envoy 2. Any help would be much appreciated.
> Bob Morgan
> KJ4SV
> 865 207 9568
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> __
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[Elecraft] KPA 500 Codan Envoy

[Bob Morgan]

I would like to know if any in the group has used the KPA 500 with a Codan
Envoy 2. Any help would be much appreciated.
Bob Morgan
KJ4SV
865 207 9568



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Re: [Elecraft] KPA-500 clicking as the temperature changes

[William Hammond via Elecraft]

I have KPA500 SN 00149.  Mine is a kit and it hasn’t had a lid off since I 
finished building it July 2, 2011, almost 9 years ago,.   Like the rest, I 
heard clicking for a while and all of a sudden it stopped or I just no longer 
hear it.  I think it stopped.  Whatever was clicking found its happy spot.

The build: 
https://www.flickr.com/photos/ak5x/albums/72157626974789347/with/5894606802/

73, Bill-AK5X

> On Jun 25, 2020, at 9:34 AM, Nr4c  wrote:
> 
> I think it’s the “Z” bracket inside. 
> 
> Sent from my iPhone
> ...nr4c. bill
> 
> 
>> On Jun 25, 2020, at 10:12 AM, Howard Sherer  wrote:
>> 
>> I have had a KPA500 for many years and the only annoying thing is that I
>> hear clicking of the metal case parts as it heats up and cools down. all of
>> the case screws are tight and I had this problem from the early days even
>> before I had to remove the RF deck and send it to the factory for minor
>> repairs 2 years ago.
>> 
>> I don't think there is a way to find the source of the clicking unless I
>> bypass the interlock and run it with the case panels off. Have others had
>> this occur and if so did you find the source and solution?
>> 
>> Howard
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Re: [Elecraft] KPA-500 clicking as the temperature changes

[Nr4c]

I think it’s the “Z” bracket inside. 

Sent from my iPhone
...nr4c. bill


> On Jun 25, 2020, at 10:12 AM, Howard Sherer  wrote:
> 
> I have had a KPA500 for many years and the only annoying thing is that I
> hear clicking of the metal case parts as it heats up and cools down. all of
> the case screws are tight and I had this problem from the early days even
> before I had to remove the RF deck and send it to the factory for minor
> repairs 2 years ago.
> 
> I don't think there is a way to find the source of the clicking unless I
> bypass the interlock and run it with the case panels off. Have others had
> this occur and if so did you find the source and solution?
> 
> Howard
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[Elecraft] KPA-500 clicking as the temperature changes

[Howard Sherer]

I have had a KPA500 for many years and the only annoying thing is that I
hear clicking of the metal case parts as it heats up and cools down. all of
the case screws are tight and I had this problem from the early days even
before I had to remove the RF deck and send it to the factory for minor
repairs 2 years ago.

I don't think there is a way to find the source of the clicking unless I
bypass the interlock and run it with the case panels off. Have others had
this occur and if so did you find the source and solution?

Howard
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Re: [Elecraft] KPA-500 Fault - follow up

[Bob McGraw K4TAX]

You will need the KAT500 Utility to perform a reset to factory values.   
That software is a free download on the Elecraft site.


While you are at it, download all the various software's for each piece 
of equipment.  i.e.  K3, P3, KPA500, KAT500.  They allow you to save 
parameters, change parameters, update firmware, and reset to factory 
values.   And always make a backup after you make changes.  That way 
should things get screwy, you can go back to your previous values.


73

Bob, K4TAX


On 5/16/2020 2:28 PM, Edward via Elecraft wrote:

All,

I tried to firmly seat all of the connectors.  No change.  I finally pulled 
them out and only used the keying cable (RCA to RCA).  No change. One thing I 
noticed is that the KAT 500 was giving me Power and SWR reading, but no 
amplification from the amplifier.   And if I had any more than 12w of drive 
power from the K3, the amp would not give me any reading at all. Dropping it 
back to under 12w, the Pwr/SWR readings would be visible again.

I decided to disconnect the antenna from the KAT 500 altogether and connected 
straight into the amp. Low and behold, I now have the amp working again!

Hence, the problem is with the KAT500 tuner.  I am thinking that a factory 
reset would do the trick. Question is, how do you reset a KAT 500 to factory 
default? The manual states to do it with a computer.  Any buttons I can push on 
the tuner itself for restoring the factory defaults?

Thanks,
Ed NI6S
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[Elecraft] KPA-500 Fault - follow up

[Edward via Elecraft]

All,

I tried to firmly seat all of the connectors.  No change.  I finally pulled 
them out and only used the keying cable (RCA to RCA).  No change. One thing I 
noticed is that the KAT 500 was giving me Power and SWR reading, but no 
amplification from the amplifier.   And if I had any more than 12w of drive 
power from the K3, the amp would not give me any reading at all. Dropping it 
back to under 12w, the Pwr/SWR readings would be visible again. 

I decided to disconnect the antenna from the KAT 500 altogether and connected 
straight into the amp. Low and behold, I now have the amp working again!  

Hence, the problem is with the KAT500 tuner.  I am thinking that a factory 
reset would do the trick. Question is, how do you reset a KAT 500 to factory 
default? The manual states to do it with a computer.  Any buttons I can push on 
the tuner itself for restoring the factory defaults?

Thanks,
Ed NI6S
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[Elecraft] KPA 500 6meter power out.

[Mike Streeter via Elecraft]

I have had this problem for some time but as I almost never use 6 meters it has 
not really concerned me.
I have two identical K Line stations, K3's, KAT 500's, KPA 500's and P3's.
On station #1 everything works as it should and if I put 25 watts into the KPA 
500 I get 500+ watts out. On station #2 if I put 30 watts into the KPA 500 I 
get 350 out and if I increase the input to 32 watts the KPA 500 momentarily 
shows 400 watts out and immediately trips the amp and shows the PA DISS fault. 
It works fine on all other bands putting out 500 watts with nominal drive power.
If I then swop the KPA 500's over without changing any antennas or radio 
settings (so nothing except the amps has changed), the fault moves with the amp 
and the good amp continues to be good on the other station.
My questions: What is wrong with the faulty amp and what do I need to do to fix 
it?
Many thanks for reading.
Mike, WM5DX.




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Re: [Elecraft] KPA-500 Issues

[Bob McGraw K4TAX]

What is the SWR?  If above the KAT500 set value it inhibits the amp from being 
keyed.  Check the KAT500 using the ATU utility. 

Bob, K4TAX


Sent from my iPhone

> On May 15, 2020, at 1:50 PM, Jack Brindle via Elecraft 
>  wrote:
> 
> 
> Check the cable connections, including making sure that none of the pins are 
> bent in the AuxIO connectors in both cables (K3S - KAT500, KAT500 - KPA500).
> Also, make sure that the PTT line is actually being asserted. The asterisk is 
> displayed when the Key In is asserted. If it isn’t displayed that means the 
> KPA is not seeing that input active. Also realize that when the KAT500 is in 
> tune mode it blocks the key line going to the KPA.
> 
> It is fairly common for someone to move something and the cable comes loose. 
> Be sure the screws are tightened down on the connectors and any adapters to 
> avoid this.
> 
> 73!
> Jack, W6FB
> 
> 
>> On May 15, 2020, at 11:07 AM, Edward via Elecraft  
>> wrote:
>> 
>> I have the combo K3S/KAT500/KPA500 with all of the optional interconnection 
>> cables. 
>> 
>> I am not able to key the amp though it was working earlier. The asterisk 
>> does not appear in the display. 
>> 
>> I went through the menu and everything is set accordingly. The inhibit is 
>> disabled. 
>> 
>> Any help would be appreciated. 
>> 
>> 73,
>> Ed NI6S
>> __
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> 
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Re: [Elecraft] KPA-500 Issues

[Jack Brindle via Elecraft]

Check the cable connections, including making sure that none of the pins are 
bent in the AuxIO connectors in both cables (K3S - KAT500, KAT500 - KPA500).
Also, make sure that the PTT line is actually being asserted. The asterisk is 
displayed when the Key In is asserted. If it isn’t displayed that means the KPA 
is not seeing that input active. Also realize that when the KAT500 is in tune 
mode it blocks the key line going to the KPA.

It is fairly common for someone to move something and the cable comes loose. Be 
sure the screws are tightened down on the connectors and any adapters to avoid 
this.

73!
Jack, W6FB


> On May 15, 2020, at 11:07 AM, Edward via Elecraft  
> wrote:
> 
> I have the combo K3S/KAT500/KPA500 with all of the optional interconnection 
> cables. 
> 
> I am not able to key the amp though it was working earlier. The asterisk does 
> not appear in the display. 
> 
> I went through the menu and everything is set accordingly. The inhibit is 
> disabled. 
> 
> Any help would be appreciated. 
> 
> 73,
> Ed NI6S
> __
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Re: [Elecraft] KPA-500 Issues

[Rick NK7I]

That implies that the AUX cable is not working.  Cycle the gear power 
and make sure each connector is properly seated.


Rick NK7I


On 5/15/2020 11:07 AM, Edward via Elecraft wrote:

I have the combo K3S/KAT500/KPA500 with all of the optional interconnection 
cables.

I am not able to key the amp though it was working earlier. The asterisk does 
not appear in the display.

I went through the menu and everything is set accordingly. The inhibit is 
disabled.

Any help would be appreciated.

73,
Ed NI6S
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[Elecraft] KPA-500 Issues

[Edward via Elecraft]

I have the combo K3S/KAT500/KPA500 with all of the optional interconnection 
cables. 

I am not able to key the amp though it was working earlier. The asterisk does 
not appear in the display. 

I went through the menu and everything is set accordingly. The inhibit is 
disabled. 

Any help would be appreciated. 

73,
Ed NI6S
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[Elecraft] KPA-500 and KAT-500 Wanted

[Jim Cary]

Looking for KPA-500 and KAT-500.  Does not need to be a package deal.

Contact me at jimlc...@gmail.com .

73,
Jim
W2SM

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Re: [Elecraft] KPA 500 fault!

[Tom Doligalski via Elecraft]

Thanks! I found the earlier manual online, and am back operational!

Thanks!

Tom W4KX

> On May 3, 2020, at 4:14 PM, iain macdonnell - N6ML  wrote:
> 
> On my early model, the interlock switch is actuated by an assembly
> including a 13mm 4-40 standoff (and some other hardware), which is
> attached to the inside of the top cover. I'll attempt to send you the
> old (rev C) assembly manual off-list.
> 
> 73,
> 
>~iain / N6ML
> 
> 
> On Sun, May 3, 2020 at 1:07 PM Tom Doligalski via Elecraft
>  wrote:
>> 
>> Problem is definitely the interlock switch not being engaged correctly: if I 
>> close it manually (with a wooden rod!) the amp operates normally.
>> 
>> Anyone have an assembly manual for the older type KPA500, so I can see how 
>> the top-panel interlock switch is supposed to be engaged? Again, this a 
>> fairly old amp, and Elecraft changed things in later versions (like the one 
>> covered in the assembly manual currently on the website).
>> 
>> Thanks!
>> 
>> Tom W4KX
>> 
>>> On May 3, 2020, at 3:21 PM, Tom Doligalski via Elecraft 
>>>  wrote:
>>> 
>>> Hi Jack!
>>> 
>>> After cycling the main power the HV in standby is back to 70 V. But, every 
>>> time I go to operate mode, the error reoccurs.
>>> 
>>> This is with what I believe was the old style interlock switch (has a shaft 
>>> attached to the top cover to engage the switch when the top is screwed 
>>> down). Can’t tell if it is properly engaging. But the behavior is the same 
>>> when the top cover is totally removed.
>>> 
>>> How picky is this switch. I bought the amp used, and the assembly manual 
>>> online at elecraft doesn’t cover the old interlock switch.
>>> 
>>> Thanks for your help!
>>> 
>>> Tom W4KX
>>> 
>>> Sent from my iPad
>>> 
 On May 3, 2020, at 3:06 PM, Jack Brindle  wrote:
 
 A “270V ERR” fault indicates that the TR switch bias supply is not 
 working. This may be caused by the top cover being removed, the safety 
 switch attached to the top cover becoming loose or an actual failure of 
 the 270V supply. Since your main HV supply is now down close to 0V, it 
 looks like you have power supply issues. You should call technical support 
 on Monday to get help.
 
 73 and good luck getting your KPA going again.
 Jack, W6FB
 
 
> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
>  wrote:
> 
> My KPA500 has been working fine waited for 115 V. Just now it has been 
> throwing a “25=70 VAC” fault!
> 
> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when 
> in standby, which is FAR from the 70 some volts it used to read.
> 
> Thanks!
> 
> Tom W4KX
> __
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Re: [Elecraft] KPA 500 fault!

[Dave Cole]

Ian,
Could you also send me a copy, I have an older amp as well.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 5/3/20 1:14 PM, iain macdonnell - N6ML wrote:

On my early model, the interlock switch is actuated by an assembly
including a 13mm 4-40 standoff (and some other hardware), which is
attached to the inside of the top cover. I'll attempt to send you the
old (rev C) assembly manual off-list.

73,

 ~iain / N6ML


On Sun, May 3, 2020 at 1:07 PM Tom Doligalski via Elecraft
 wrote:


Problem is definitely the interlock switch not being engaged correctly: if I 
close it manually (with a wooden rod!) the amp operates normally.

Anyone have an assembly manual for the older type KPA500, so I can see how the 
top-panel interlock switch is supposed to be engaged? Again, this a fairly old 
amp, and Elecraft changed things in later versions (like the one covered in the 
assembly manual currently on the website).

Thanks!

Tom W4KX


On May 3, 2020, at 3:21 PM, Tom Doligalski via Elecraft 
 wrote:

Hi Jack!

After cycling the main power the HV in standby is back to 70 V. But, every time 
I go to operate mode, the error reoccurs.

This is with what I believe was the old style interlock switch (has a shaft 
attached to the top cover to engage the switch when the top is screwed down). 
Can’t tell if it is properly engaging. But the behavior is the same when the 
top cover is totally removed.

How picky is this switch. I bought the amp used, and the assembly manual online 
at elecraft doesn’t cover the old interlock switch.

Thanks for your help!

Tom W4KX

Sent from my iPad


On May 3, 2020, at 3:06 PM, Jack Brindle  wrote:

A “270V ERR” fault indicates that the TR switch bias supply is not working. 
This may be caused by the top cover being removed, the safety switch attached 
to the top cover becoming loose or an actual failure of the 270V supply. Since 
your main HV supply is now down close to 0V, it looks like you have power 
supply issues. You should call technical support on Monday to get help.

73 and good luck getting your KPA going again.
Jack, W6FB



On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
 wrote:

My KPA500 has been working fine waited for 115 V. Just now it has been throwing 
a “25=70 VAC” fault!

Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in 
standby, which is FAR from the 70 some volts it used to read.

Thanks!

Tom W4KX
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Re: [Elecraft] KPA 500 fault!

[iain macdonnell - N6ML]

On my early model, the interlock switch is actuated by an assembly
including a 13mm 4-40 standoff (and some other hardware), which is
attached to the inside of the top cover. I'll attempt to send you the
old (rev C) assembly manual off-list.

73,

~iain / N6ML


On Sun, May 3, 2020 at 1:07 PM Tom Doligalski via Elecraft
 wrote:
>
> Problem is definitely the interlock switch not being engaged correctly: if I 
> close it manually (with a wooden rod!) the amp operates normally.
>
> Anyone have an assembly manual for the older type KPA500, so I can see how 
> the top-panel interlock switch is supposed to be engaged? Again, this a 
> fairly old amp, and Elecraft changed things in later versions (like the one 
> covered in the assembly manual currently on the website).
>
> Thanks!
>
> Tom W4KX
>
> > On May 3, 2020, at 3:21 PM, Tom Doligalski via Elecraft 
> >  wrote:
> >
> > Hi Jack!
> >
> > After cycling the main power the HV in standby is back to 70 V. But, every 
> > time I go to operate mode, the error reoccurs.
> >
> > This is with what I believe was the old style interlock switch (has a shaft 
> > attached to the top cover to engage the switch when the top is screwed 
> > down). Can’t tell if it is properly engaging. But the behavior is the same 
> > when the top cover is totally removed.
> >
> > How picky is this switch. I bought the amp used, and the assembly manual 
> > online at elecraft doesn’t cover the old interlock switch.
> >
> > Thanks for your help!
> >
> > Tom W4KX
> >
> > Sent from my iPad
> >
> >> On May 3, 2020, at 3:06 PM, Jack Brindle  wrote:
> >>
> >> A “270V ERR” fault indicates that the TR switch bias supply is not 
> >> working. This may be caused by the top cover being removed, the safety 
> >> switch attached to the top cover becoming loose or an actual failure of 
> >> the 270V supply. Since your main HV supply is now down close to 0V, it 
> >> looks like you have power supply issues. You should call technical support 
> >> on Monday to get help.
> >>
> >> 73 and good luck getting your KPA going again.
> >> Jack, W6FB
> >>
> >>
> >>> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
> >>>  wrote:
> >>>
> >>> My KPA500 has been working fine waited for 115 V. Just now it has been 
> >>> throwing a “25=70 VAC” fault!
> >>>
> >>> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when 
> >>> in standby, which is FAR from the 70 some volts it used to read.
> >>>
> >>> Thanks!
> >>>
> >>> Tom W4KX
> >>> __
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> >>
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Re: [Elecraft] KPA 500 fault!

[Tom Doligalski via Elecraft]

Problem is definitely the interlock switch not being engaged correctly: if I 
close it manually (with a wooden rod!) the amp operates normally. 

Anyone have an assembly manual for the older type KPA500, so I can see how the 
top-panel interlock switch is supposed to be engaged? Again, this a fairly old 
amp, and Elecraft changed things in later versions (like the one covered in the 
assembly manual currently on the website). 

Thanks!

Tom W4KX

> On May 3, 2020, at 3:21 PM, Tom Doligalski via Elecraft 
>  wrote:
> 
> Hi Jack!
> 
> After cycling the main power the HV in standby is back to 70 V. But, every 
> time I go to operate mode, the error reoccurs. 
> 
> This is with what I believe was the old style interlock switch (has a shaft 
> attached to the top cover to engage the switch when the top is screwed down). 
> Can’t tell if it is properly engaging. But the behavior is the same when the 
> top cover is totally removed. 
> 
> How picky is this switch. I bought the amp used, and the assembly manual 
> online at elecraft doesn’t cover the old interlock switch. 
> 
> Thanks for your help!
> 
> Tom W4KX
> 
> Sent from my iPad 
> 
>> On May 3, 2020, at 3:06 PM, Jack Brindle  wrote:
>> 
>> A “270V ERR” fault indicates that the TR switch bias supply is not working. 
>> This may be caused by the top cover being removed, the safety switch 
>> attached to the top cover becoming loose or an actual failure of the 270V 
>> supply. Since your main HV supply is now down close to 0V, it looks like you 
>> have power supply issues. You should call technical support on Monday to get 
>> help.
>> 
>> 73 and good luck getting your KPA going again.
>> Jack, W6FB
>> 
>> 
>>> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
>>>  wrote:
>>> 
>>> My KPA500 has been working fine waited for 115 V. Just now it has been 
>>> throwing a “25=70 VAC” fault!
>>> 
>>> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in 
>>> standby, which is FAR from the 70 some volts it used to read. 
>>> 
>>> Thanks!
>>> 
>>> Tom W4KX
>>> __
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>> 
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Re: [Elecraft] KPA 500 fault!

[Tom Doligalski via Elecraft]

Hi Jack!

After cycling the main power the HV in standby is back to 70 V. But, every time 
I go to operate mode, the error reoccurs. 

This is with what I believe was the old style interlock switch (has a shaft 
attached to the top cover to engage the switch when the top is screwed down). 
Can’t tell if it is properly engaging. But the behavior is the same when the 
top cover is totally removed. 

How picky is this switch. I bought the amp used, and the assembly manual online 
at elecraft doesn’t cover the old interlock switch. 

Thanks for your help!

Tom W4KX

Sent from my iPad 

> On May 3, 2020, at 3:06 PM, Jack Brindle  wrote:
> 
> A “270V ERR” fault indicates that the TR switch bias supply is not working. 
> This may be caused by the top cover being removed, the safety switch attached 
> to the top cover becoming loose or an actual failure of the 270V supply. 
> Since your main HV supply is now down close to 0V, it looks like you have 
> power supply issues. You should call technical support on Monday to get help.
> 
> 73 and good luck getting your KPA going again.
> Jack, W6FB
> 
> 
>> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
>>  wrote:
>> 
>> My KPA500 has been working fine waited for 115 V. Just now it has been 
>> throwing a “25=70 VAC” fault!
>> 
>> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in 
>> standby, which is FAR from the 70 some volts it used to read. 
>> 
>> Thanks!
>> 
>> Tom W4KX
>> __
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Re: [Elecraft] KPA 500 fault!

[Jack Brindle via Elecraft]

A “270V ERR” fault indicates that the TR switch bias supply is not working. 
This may be caused by the top cover being removed, the safety switch attached 
to the top cover becoming loose or an actual failure of the 270V supply. Since 
your main HV supply is now down close to 0V, it looks like you have power 
supply issues. You should call technical support on Monday to get help.

73 and good luck getting your KPA going again.
Jack, W6FB


> On May 3, 2020, at 11:32 AM, Tom Doligalski via Elecraft 
>  wrote:
> 
> My KPA500 has been working fine waited for 115 V. Just now it has been 
> throwing a “25=70 VAC” fault!
> 
> Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in 
> standby, which is FAR from the 70 some volts it used to read. 
> 
> Thanks!
> 
> Tom W4KX
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[Elecraft] KPA 500 fault!

[Tom Doligalski via Elecraft]

My KPA500 has been working fine waited for 115 V. Just now it has been throwing 
a “25=70 VAC” fault!

Can anyone lead me in helping this? Fuses look good. HV read 0.1 v when in 
standby, which is FAR from the 70 some volts it used to read. 

Thanks!

Tom W4KX
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Re: [Elecraft] KPA 500

[Andy Durbin]

"60 deg C with fan not running is not normal.  60 deg C is the nominal 
temperature for start of fan speed 3."

The conversation was continued off "list" but there are a few points that I'd 
like to be in the archive - 

There would appear to be two possible failure conditions.  Either the fan is 
not being commanded on when temperature exceeds 50 deg C or the fan is 
commanded on and does not run.

Fan speed 1 is easily heard by anyone with normal hearing.  The fan isn't quiet.

Fan operation at all speeds can be tested by using the KPA500 menu to select 
FAN CTL and cycling though the speeds.

Commanded fan speed can be checked by using the KPA500 utility to send command 
"^FS;".  It will return "^FS0x;"  where x is the fan speed setting.

73,
Andy, k3wyc









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Re: [Elecraft] KPA 500

[Michael Walker]

This is going to cause a big sh*t storm :) and about 900 emails before
Wayne shuts it down.

However, having been in RF for a bit less then most of you (only 1974), I
have had connectors fail and not fail in my HF world (60Mhz or less).

No Name ones have worked wonderfully for decades.  Amphenol's have failed
in a year.   Amphenol T's in a phasing harness seem to fail the most (fell
apart).  But, then, who knows who makes them.

What I can say is that there is, based on my personal experience, no 100%
guarantee on any particular one.

Install it.  Visually inspect it.  Make sure it is clean, dry and
waterproof and a year from now, if it is outside, open it up and make sure
it is still dry.

It isn't eve 'you get what you pay for' any more.

Next, we can have another 200 emails on how to solder a PL259.  :)

Mike va3mw




On Fri, Apr 10, 2020 at 4:37 PM Ed Pflueger  wrote:

> Well I was told by an unreliable source that the military had to have their
> Amphenol's manufactured in the USA but were sent to Mexico for packaging.
> Whether that's true or not I cannot confirm.  All I know is the ones I buy
> are stamped in black lettering saying "Amphenol 83-1sp and below that  is
> 74868 PL259 49190" and they can run around 4 bucks apiece depending on when
> and where I get them.
>
> Ed... AB4IQ
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net
> [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
> Sent: Friday, April 10, 2020 11:27 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] KPA 500
>
> On 4/10/2020 8:45 AM, Irwin Darack wrote:
> > In my experience, coax connectors, barrel connectors, etc. are always
> > fail points when there is a sudden increase in SWR as power is
> > increased. They oxidize over time and sometimes just reconnecting or
> > replacing is the first step before taking the amp apart.
>
> If this is happening, I'd suspect 1) the connectors have gotten wet or
> 2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
> JUNK.
>
> 73, Jim K9YC
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Re: [Elecraft] KPA 500

[Ed Pflueger]

Well I was told by an unreliable source that the military had to have their
Amphenol's manufactured in the USA but were sent to Mexico for packaging.
Whether that's true or not I cannot confirm.  All I know is the ones I buy
are stamped in black lettering saying "Amphenol 83-1sp and below that  is
74868 PL259 49190" and they can run around 4 bucks apiece depending on when
and where I get them.

Ed... AB4IQ

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Friday, April 10, 2020 11:27 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA 500

On 4/10/2020 8:45 AM, Irwin Darack wrote:
> In my experience, coax connectors, barrel connectors, etc. are always 
> fail points when there is a sudden increase in SWR as power is 
> increased. They oxidize over time and sometimes just reconnecting or 
> replacing is the first step before taking the amp apart.

If this is happening, I'd suspect 1) the connectors have gotten wet or
2) the are JUNK connectors. If they aren't labeled "Amphenol," they're JUNK.

73, Jim K9YC
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Re: [Elecraft] KPA 500

[Raymond Sills via Elecraft]

That just goes to prove the point: Chinese manufacturers will build to whatever 
quality level you specify.  Consider things like the iPhone and other similar 
devices.  Most people don't complain about the quality of their iPhone or iPad.
73 de RayK2ULR


-Original Message-
From: Buck 
To: elecraft 
Sent: Fri, Apr 10, 2020 1:23 pm
Subject: Re: [Elecraft] KPA 500

A vendor at Dayton told me *all* are made in China, even the ones marked 
Amphenol.

k4ia, Buck
K3s# 11497
Honor Roll  8B DXCC
EasyWayHamBooks.com

On 4/10/2020 12:43 PM, Irwin Darack wrote:
> Agreed. Many people buy the cheap ones made in Chinaand they fail.
> 
> Irwin KD3TB
> 
>>> step before taking the amp apart.
>>
>> If this is happening, I'd suspect 1) the connectors have gotten wet or
>> 2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
>> JUNK.
>>
>> 73, Jim K9YC
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>>
> 
> 
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[Elecraft] KPA 500

[Andy Durbin]

"After transmitting at 200W the temperature slowly 
rises above 60 degrees C, but the fan doesn't cut in. Does anyone know 
if this is normal behavior and what temperatures I should expect to see?"

Nominal temperature for start of fan speed 1 is 50 deg C although my data for 
one test run showed several seconds at 50 deg C and fan not running.  It 
started running just before the temperature rose to 51 deg C.

60 deg C with fan not running is not normal.  60 deg C is the nominal 
temperature for start of fan speed 3.

73,
Andy, k3wyc


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Re: [Elecraft] KPA 500

[Josh Fiden]

That’s likely true. But if he’s saying they’re the same as Chinese brand, 
that’s nonsense. 

I use a lot of connectors from Amphenol Audio which are made in China. The 
difference between Amphenol & equivalent Chinese is obvious on inspection. 
Mating is very solid and contact plating looks much nicer. Price difference 
about double. I think the Amphenol connectors are very fairly priced 
considering the quality differences. I believe the same about their RF 
connectors. 

73
Josh W6XU

Sent from my mobile device

> On Apr 10, 2020, at 10:20 AM, Buck  wrote:
> 
> A vendor at Dayton told me *all* are made in China, even the ones marked 
> Amphenol.

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Re: [Elecraft] KPA 500

[Lyn Norstad]

Many thanks to all who offered me solutions both on and off the list.

But let me clarify ... I wasn't looking for help.  My system and my station
are performing very well, and I love it.

I was merely offering up my experience in response to Alan, G4GNX's question
(below).

73
Lyn, WØLEN



-Original Message-
From: Lyn Norstad [mailto:l...@lnainc.com] 
Sent: Friday, April 10, 2020 8:59 AM
To: 'Alan - G4GNX'; 'Elecraft Reflector'
Subject: RE: [Elecraft] KPA 500

At 100w on 20m, my KAT500 Utility shows an SWR of 1.00 with the KPA500 on
Standby and temp around 38ºC.  But as I switch the KPA to Operate and
increase the power to 300w the SWR goes up as high as 1.10.  If I hold it
there (key down) long enough the KPA temp starts rising slowly.  At about
50ºC I can hear the fan picking up speed.  By the time I get to 60ºC the fan
is at probably level 2 or 3.  SWR is still at 1.10 (max).
Right or wrong, I've always assumed there is some slight heating in the
antenna system (Tuner, Balun, Lightning protection) although all components
after the tuner are rated at 5 KW.
73
Lyn, WØLEN

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Alan - G4GNX
Sent: Friday, April 10, 2020 6:27 AM
To: Elecraft Reflector
Subject: [Elecraft] KPA 500


I have a strange fault a couple of times recently, where the SWR starts 
to increase during the time of a single 'over'. I've been using the K3S 
set at 100W out, via the KPA500 (in standby) and the KAT500 tuner, 
without any problem, but after I've switched the linear to Operate and 
driving it to 200W, the SWR creeps up. I don't think it's an antenna 
issue, but a possible heat problem with the KPA500. I watched the 
temperature display on the KPA500 and initially on Standby it shows 
about 38 degrees C. After transmitting at 200W the temperature slowly 
rises above 60 degrees C, but the fan doesn't cut in. Does anyone know 
if this is normal behavior and what temperatures I should expect to see? 
I have tested the fan via the Menu function and it works as expected.

73,

Alan. G4GNX 

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Re: [Elecraft] KPA 500

[Jim Brown]

On 4/10/2020 10:19 AM, Buck wrote:
A vendor at Dayton told me *all* are made in China, even the ones marked 
Amphenol.


Um, Apple products have long been made in China. Fair-Rite has had one 
or more factories in China for more than a decade. "Made in China" does 
NOT define the product as junk. Last I heard, Amphenol is making 
connectors in Mexico. Having bought and installed several hundred in the 
last decade, the only faults I've found are a few whose screw threads 
were short.


And you trust someone working in a trade show booth to know this? 
Someone selling junk connectors who disparages a competitor?


73, Jim K9YC


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Re: [Elecraft] KPA 500

[Lyn Norstad]

Randy –

 

I’m not the one with issues, it was Alan.  I just offered up my experience for 
his comparison.

 

73

Lyn, WØLEN

 

 

From: Ted Edwards W3TB [mailto:w3tb@gmail.com] 
Sent: Friday, April 10, 2020 10:32 AM
To: Randy Farmer
Cc: l...@lnainc.com; elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA 500

 

I am watching this with great interest.  If running stations on CW my KPA500 
shows low-mid 50sC and I have never known what it should be.  Thanks everyone.

 

On Fri, Apr 10, 2020 at 10:27 Randy Farmer  wrote:

If the initial VSWR is really measuring 1.00:1 with low power, that 
means the detected reflected power is exceptionally low. I'm sure the 
algorithm used to compute SWR sets it to 1:1 if there's zero reflected 
power. If the load is not really perfectly flat, as the incident power 
is increased the detector will finally see enough reflected energy to 
give an indication. You have absolutely nothing to worry about in your 
system.

73...
Randy, W8FN


On 4/10/2020 9:59 AM, Lyn Norstad wrote:
> At 100w on 20m, my KAT500 Utility shows an SWR of 1.00 with the KPA500 on
> Standby and temp around 38ºC.  But as I switch the KPA to Operate and
> increase the power to 300w the SWR goes up as high as 1.10.  If I hold it
> there (key down) long enough the KPA temp starts rising slowly.  At about
> 50ºC I can hear the fan picking up speed.  By the time I get to 60ºC the fan
> is at probably level 2 or 3.  SWR is still at 1.10 (max).
> Right or wrong, I've always assumed there is some slight heating in the
> antenna system (Tuner, Balun, Lightning protection) although all components
> after the tuner are rated at 5 KW.
> 73
> Lyn, WØLEN
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-- 

73 de Ted Edwards, W3TB and GØPWW

and thinking about operating CW:
"Do today what others won't,
so you can do tomorrow what others can't."

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Re: [Elecraft] KPA 500

[Bob McGraw K4TAX]

I try and spend the time to recover OLD PL-259 connectors.  I have some 
which I've owned for 30 to 40 years.  They are ugly, tarnished, and may 
have phenolic insulatorsbut are darn good connectors.    When I 
encounter a bad or connector, I usually chop the connector off with 
about 1" of cable remaining and toss it in a box.  Speaking of which, 
I'd say there are 10 to 15 pieces of RG-8 type cable in my junk cable 
box that I could recover today.  Worthwhile project.


73

Bob, K4TAX


On 4/10/2020 12:19 PM, Buck wrote:
A vendor at Dayton told me *all* are made in China, even the ones 
marked Amphenol.


k4ia, Buck
K3s# 11497
Honor Roll  8B DXCC
EasyWayHamBooks.com

On 4/10/2020 12:43 PM, Irwin Darack wrote:

Agreed. Many people buy the cheap ones made in Chinaand they fail.

Irwin KD3TB

On Fri, Apr 10, 2020 at 12:28 PM Jim Brown 
wrote:


On 4/10/2020 8:45 AM, Irwin Darack wrote:

In my experience, coax connectors, barrel connectors, etc. are always

fail
points when there is a sudden increase in SWR as power is 
increased. They

oxidize over time and sometimes just reconnecting or replacing is the

first

step before taking the amp apart.


If this is happening, I'd suspect 1) the connectors have gotten wet or
2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
JUNK.

73, Jim K9YC
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Re: [Elecraft] KPA 500

[Dave Cole]

Amphenol more than likely does QC...  So I would expect the majority of 
their connectors to be better than the possibly non QC tested 
connectors.  I doubt most resellers QC the connectors.  I am sure some 
do, but I would love to know which ones do.


73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 4/10/20 10:19 AM, Buck wrote:
A vendor at Dayton told me *all* are made in China, even the ones marked 
Amphenol.


k4ia, Buck
K3s# 11497
Honor Roll  8B DXCC
EasyWayHamBooks.com

On 4/10/2020 12:43 PM, Irwin Darack wrote:

Agreed. Many people buy the cheap ones made in Chinaand they fail.

Irwin KD3TB

On Fri, Apr 10, 2020 at 12:28 PM Jim Brown 
wrote:


On 4/10/2020 8:45 AM, Irwin Darack wrote:

In my experience, coax connectors, barrel connectors, etc. are always

fail
points when there is a sudden increase in SWR as power is increased. 
They

oxidize over time and sometimes just reconnecting or replacing is the

first

step before taking the amp apart.


If this is happening, I'd suspect 1) the connectors have gotten wet or
2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
JUNK.

73, Jim K9YC
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Re: [Elecraft] KPA 500

[Buck]

A vendor at Dayton told me *all* are made in China, even the ones marked 
Amphenol.


k4ia, Buck
K3s# 11497
Honor Roll  8B DXCC
EasyWayHamBooks.com

On 4/10/2020 12:43 PM, Irwin Darack wrote:

Agreed. Many people buy the cheap ones made in Chinaand they fail.

Irwin KD3TB

On Fri, Apr 10, 2020 at 12:28 PM Jim Brown 
wrote:


On 4/10/2020 8:45 AM, Irwin Darack wrote:

In my experience, coax connectors, barrel connectors, etc. are always

fail

points when there is a sudden increase in SWR as power is increased. They
oxidize over time and sometimes just reconnecting or replacing is the

first

step before taking the amp apart.


If this is happening, I'd suspect 1) the connectors have gotten wet or
2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
JUNK.

73, Jim K9YC
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Re: [Elecraft] KPA 500

[Bob McGraw K4TAX]

My first question is "what does it do on a dummy load?"  Sounds like 
something related to a bad or questionable jumper cable, loose connector 
or bad connectors.   I find many of today's connectors have machining 
tolerance errors and more so, have only "good looking" plating.  While 
in fact, many of these are poor quality.


I find that PL-259 connectors must be mated correctly in that the body 
of the connector has 2 small triangle shaped protrusions from the body 
of the connector that must be mated with the notches on the SO-239 
connector.   Failure to do this will allow the connector to loosen under 
use.   And then the shell of the connector must be tightened a bit more 
than finger tight.   I keep a 4" pair of Channel Locks on the desk to 
help remove and tighten connectors.   If not done so, the heating and 
cooling of the connector will allow it to loosen and not make good contact.


Regarding the KPA500 temperature:  With my amp this morning { S/N 3519 
Firmware 01.54 }  at turn on 18C,  I then held it at 500 watts carrier 
output into a 50 ohm dummy load.  At 50C fan on 1 speed, at 55C fan on 2 
speed.   This took about 210 seconds (3.5 minutes) from cold start to 
55C on 80M into the dummy load. Other bands are less efficient and one 
could expect a faster temperature rise in less time.  It does vary from 
band to band and antenna load to load.  I did not observe any change in 
SWR indication, either on the amp LED display or my Bird 43 between the 
amp output and the dummy load.


Hope this helps.

73

Bob, K4TAX


On 4/10/2020 6:26 AM, Alan - G4GNX wrote:


I have a strange fault a couple of times recently, where the SWR 
starts to increase during the time of a single 'over'. I've been using 
the K3S set at 100W out, via the KPA500 (in standby) and the KAT500 
tuner, without any problem, but after I've switched the linear to 
Operate and driving it to 200W, the SWR creeps up. I don't think it's 
an antenna issue, but a possible heat problem with the KPA500. I 
watched the temperature display on the KPA500 and initially on Standby 
it shows about 38 degrees C. After transmitting at 200W the 
temperature slowly rises above 60 degrees C, but the fan doesn't cut 
in. Does anyone know if this is normal behavior and what temperatures 
I should expect to see? I have tested the fan via the Menu function 
and it works as expected.


73,

Alan. G4GNX

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Re: [Elecraft] KPA 500

[Irwin Darack]

Agreed. Many people buy the cheap ones made in Chinaand they fail.

Irwin KD3TB

On Fri, Apr 10, 2020 at 12:28 PM Jim Brown 
wrote:

> On 4/10/2020 8:45 AM, Irwin Darack wrote:
> > In my experience, coax connectors, barrel connectors, etc. are always
> fail
> > points when there is a sudden increase in SWR as power is increased. They
> > oxidize over time and sometimes just reconnecting or replacing is the
> first
> > step before taking the amp apart.
>
> If this is happening, I'd suspect 1) the connectors have gotten wet or
> 2) the are JUNK connectors. If they aren't labeled "Amphenol," they're
> JUNK.
>
> 73, Jim K9YC
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-- 
Irwin KD3TB
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Re: [Elecraft] KPA 500

[Jim Brown]

On 4/10/2020 8:45 AM, Irwin Darack wrote:

In my experience, coax connectors, barrel connectors, etc. are always fail
points when there is a sudden increase in SWR as power is increased. They
oxidize over time and sometimes just reconnecting or replacing is the first
step before taking the amp apart.


If this is happening, I'd suspect 1) the connectors have gotten wet or 
2) the are JUNK connectors. If they aren't labeled "Amphenol," they're JUNK.


73, Jim K9YC
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