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KXPA100 SN 707 Total Frustration with this Amp

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rldillon

KXPA100 SN 707 Total Frustration with this Amp

Upfront this email is long and outlines the frustrations with this amp that I have never encountered with another piece of new Ham Equipment in my 27 years of being licensed.

First indication of Problem:

I received this amp on 27 Feb at 10:55 when the situation started. I unpacked the items and laid them out on the table with an anti-static mat in place. As I inventoried the items, I discovered that I had two back plates and no face plate. I started assembly of the amp and noticed that the hex nut for the RS232 (PC) connector was missing. I looked in the parts bag and it was not there either. I sent an email to parts at Elecraft and received a phone call asking to describe what was missing. I described in detail what was missing and received a promise that correct parts would be shipped.

Front Plate and hex nut were shipped via USPS on 3 March and received in WV on 5 March. I installed the front plate and then opened the small envelope with the hex nut. It was the wrong one. I sent another email to Parts at Elecraft with an attached picture showing that the part sent was the wrong one.

The correct part was shipped 6 Mar and received 8 Mar. I installed and hooked up the amp today (see comments below for todays adventure).

What has really caused the frustrations with this amp.

After the weekend ARRL Contest, I hooked the amp to the KX3 per the manual by setting Tun Power to nor and PA MODE to on. The amp immediately came to life. I adjusted the power knob and noticed that the power was now showing what the amp would output versus the KX3 power. There was station on 20 RTTY that I wanted to work so I set the output power to 45 watts which would drive the AL80B to just between 400 to 500 watts. Tuner after the AL80B is a Palstar AT4K into a Hexx Beam with an swr of 1.2 on 20M with tuner bypassed. I started up kcomm and entered the stations call. I heard the AL80B amp keying each time I sent my call. I tried several times with no contact with the station calling CQ. I keyed again and noticed that the al80B was only showing about 30-40 watts instead of 4-500. I immediately stopped sending call and exited kcomm, started the KXPA utility program and found the fault table. It showed several faults for hi swr of 99.9:1. How do you get an swr this high into
an antenna with an swr of 1.2? I went back into the kx3 menu and turned off PA mode. I then set kx3 power to 10 watts and keyed with amp turned off. SWR showing on KX3 was 1.3. I turned amp on and keyed up with another fault for Hi SWR. I did work the station with my TS590, AL80B, Palstar tuner and hex with NO SWR problems!!

I tried more bands with the same problems. I downloaded the Beta Firmware and new utility and updated the firmware. Same problems and results. I swapped out the coax between the KXPA100 and the AL80B. Same results. I swapped out the coax that came with the KXPA cable package with a known good jumper to the amp same results. I bypassed the AL80b and Palstar tuner direct to the hex. Hi SWR faults. I tried dipole with Palstar same results. I added an LDG Auto tuner after amp with same results.

I reloaded ver 1.04 of the firmware and tried again same results. I also reloaded the beta a second time.

Today I hooked the amp back up after installing the correct hex and decided to try some more trouble shooting. Today with the PA Mode on and running the utility software, If I uncheck PA Bypass, which comes on with equipment turn on, the PA Bypass comes back on. I can hear the relays clicking each time. If I change PA Mode so I can manually turn the amp off and on the PA Bypass works correctly. I changed the short piece of CAT 5 with a piece of fully shielded CAT 6. Did not make a difference.

I saw on the reflector an individual having problems with tuner retuning during a qso due to sensitive SWR . This is not my situation as mine does not have a tuner and is a kit version. I also saw where an individual had a problem using an LDG auto tuner. That is also not a symptom I am having as LDG tuner tunes fine when you use at least 5 watts or so to tune.

Any suggestions would be appreciated. I have totally lost any faith or confidence in the amp. As one of my friends told me it is probably time for it go away.

Rich, K8VE

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Dr. William J. Schmidt, II

Re: KXPA100 SN 707 Total Frustration with this Amp

Am I reading this correctly? You are driving an AL80B with the KXPA100
being driven by the KX3? That's quite imaginative if that's correct. The
SWR fault is coming from the AL80B input circuit not your antenna (the KXPA
can't see the SWR on the other side of the AL80B). probably something bad
in the input circuit of the AL80B causing the high SWR...

Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ

Owner - Operator
Big Signal Ranch
Staunton, Illinois

email: [hidden email]

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Sunday, March 09, 2014 7:24 PM
To: [hidden email]; [hidden email]
Subject: [Elecraft] KXPA100 SN 707 Total Frustration with this Amp

Upfront this email is long and outlines the frustrations with this amp that
I have never encountered with another piece of new Ham Equipment in my 27
years of being licensed.

First indication of Problem:

I received this amp on 27 Feb at 10:55 when the situation started. I
unpacked the items and laid them out on the table with an anti-static mat in
place. As I inventoried the items, I discovered that I had two back plates
and no face plate. I started assembly of the amp and noticed that the hex
nut for the RS232 (PC) connector was missing. I looked in the parts bag and
it was not there either. I sent an email to parts at Elecraft and received a
phone call asking to describe what was missing. I described in detail what
was missing and received a promise that correct parts would be shipped.

Front Plate and hex nut were shipped via USPS on 3 March and received in WV
on 5 March. I installed the front plate and then opened the small envelope
with the hex nut. It was the wrong one. I sent another email to Parts at
Elecraft with an attached picture showing that the part sent was the wrong
one.

The correct part was shipped 6 Mar and received 8 Mar. I installed and
hooked up the amp today (see comments below for todays adventure).

What has really caused the frustrations with this amp.

After the weekend ARRL Contest, I hooked the amp to the KX3 per the manual
by setting Tun Power to nor and PA MODE to on. The amp immediately came to
life. I adjusted the power knob and noticed that the power was now showing
what the amp would output versus the KX3 power. There was station on 20 RTTY
that I wanted to work so I set the output power to 45 watts which would
drive the AL80B to just between 400 to 500 watts. Tuner after the AL80B is a
Palstar AT4K into a Hexx Beam with an swr of 1.2 on 20M with tuner bypassed.
I started up kcomm and entered the stations call. I heard the AL80B amp
keying each time I sent my call. I tried several times with no contact with
the station calling CQ. I keyed again and noticed that the al80B was only
showing about 30-40 watts instead of 4-500. I immediately stopped sending
call and exited kcomm, started the KXPA utility program and found the fault
table. It showed several faults for hi swr of 99.9:1. How do you get an swr
this high into
an antenna with an swr of 1.2? I went back into the kx3 menu and turned
off PA mode. I then set kx3 power to 10 watts and keyed with amp turned off.
SWR showing on KX3 was 1.3. I turned amp on and keyed up with another fault
for Hi SWR. I did work the station with my TS590, AL80B, Palstar tuner and
hex with NO SWR problems!!

I tried more bands with the same problems. I downloaded the Beta Firmware
and new utility and updated the firmware. Same problems and results. I
swapped out the coax between the KXPA100 and the AL80B. Same results. I
swapped out the coax that came with the KXPA cable package with a known good
jumper to the amp same results. I bypassed the AL80b and Palstar tuner
direct to the hex. Hi SWR faults. I tried dipole with Palstar same results.
I added an LDG Auto tuner after amp with same results.

I reloaded ver 1.04 of the firmware and tried again same results. I also
reloaded the beta a second time.

Today I hooked the amp back up after installing the correct hex and decided
to try some more trouble shooting. Today with the PA Mode on and running the
utility software, If I uncheck PA Bypass, which comes on with equipment turn
on, the PA Bypass comes back on. I can hear the relays clicking each time.
If I change PA Mode so I can manually turn the amp off and on the PA Bypass
works correctly. I changed the short piece of CAT 5 with a piece of fully
shielded CAT 6. Did not make a difference.

I saw on the reflector an individual having problems with tuner retuning
during a qso due to sensitive SWR . This is not my situation as mine does
not have a tuner and is a kit version. I also saw where an individual had a
problem using an LDG auto tuner. That is also not a symptom I am having as
LDG tuner tunes fine when you use at least 5 watts or so to tune.

Any suggestions would be appreciated. I have totally lost any faith or
confidence in the amp. As one of my friends told me it is probably time for
it go away.

Rich, K8VE

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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______________________________________________________________
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rldillon

Re: KXPA100 SN 707 Total Frustration with this Amp

The high SWR happens even when the AL80b or Palstar tuner is not connected. In other words when coax from the kpxa100 goes direct to the K4KIO Hexx beam with nothing in between to confuse the amp except a barrel connector.

Yes you can drive a larger amp with the kx3 and KXPA100. It is covered on page 19 of the manual in paragraph titled Keying an External Amplifier.

-----Original Message-----
From: Dr. William J. Schmidt, II <[hidden email]>
To: rldillon <[hidden email]>; elecraft <[hidden email]>; KX3 <[hidden email]>
Sent: Sun, Mar 9, 2014 8:49 pm
Subject: RE: [Elecraft] KXPA100 SN 707 Total Frustration with this Amp

Am I reading this correctly? You are driving an AL80B with the KXPA100
being driven by the KX3? That's quite imaginative if that's correct. The
SWR fault is coming from the AL80B input circuit not your antenna (the KXPA
can't see the SWR on the other side of the AL80B). probably something bad
in the input circuit of the AL80B causing the high SWR...

Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ

Owner - Operator
Big Signal Ranch
Staunton, Illinois

email: [hidden email]

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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Brian Hunt

Re: KXPA100 SN 707 Total Frustration with this Amp

Have you tried any testing with a 50 ohm dummy load? After the KX3, after the KXPA, after the AL80b? Seems like that would let you isolate who the culprit is.

Just my $0.02

Brian. K0DTJ

> On Mar 9, 2014, at 18:07, [hidden email] wrote:
>
>
> The high SWR happens even when the AL80b or Palstar tuner is not connected. In other words when coax from the kpxa100 goes direct to the K4KIO Hexx beam with nothing in between to confuse the amp except a barrel connector.
>
> Yes you can drive a larger amp with the kx3 and KXPA100. It is covered on page 19 of the manual in paragraph titled Keying an External Amplifier.
>
>
> -----Original Message-----
> From: Dr. William J. Schmidt, II <[hidden email]>
> To: rldillon <[hidden email]>; elecraft <[hidden email]>; KX3 <[hidden email]>
> Sent: Sun, Mar 9, 2014 8:49 pm
> Subject: RE: [Elecraft] KXPA100 SN 707 Total Frustration with this Amp
>
>
> Am I reading this correctly? You are driving an AL80B with the KXPA100
> being driven by the KX3? That's quite imaginative if that's correct. The
> SWR fault is coming from the AL80B input circuit not your antenna (the KXPA
> can't see the SWR on the other side of the AL80B). probably something bad
> in the input circuit of the AL80B causing the high SWR...
>
>
> Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ
>
> Owner - Operator
> Big Signal Ranch
> Staunton, Illinois
>
> email: [hidden email]
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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Vic Rosenthal

Re: KXPA100 SN 707 Total Frustration with this Amp

In reply to this post by rldillon

Dennis Moore

Re: KXPA100 SN 707 Total Frustration with this Amp

In reply to this post by rldillon

What do you get when transmitting into a dummy load with a known good
coax jumper? Just curious.

73, Dennis NJ6G

On 3/9/2014 6:07 PM, [hidden email] wrote:
> The high SWR happens even when the AL80b or Palstar tuner is not connected. In other words when coax from the kpxa100 goes direct to the K4KIO Hexx beam with nothing in between to confuse the amp except a barrel connector.
>
> Yes you can drive a larger amp with the kx3 and KXPA100. It is covered on page 19 of the manual in paragraph titled Keying an External Amplifier.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
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John Marvin

Re: [KX3] Re: KXPA100 SN 707 Total Frustration with this Amp

In reply to this post by rldillon

The suggestions to try a dummy load first are right on. Do you have the
built in ATU, or just the KXPA 100? If you have the ATU I would try both
antenna outputs.

If I had to guess what the problem is I would guess that you didn't seat
the antenna connector from the back panel correctly to the atu board (or
main board if you don't have the ATU) when you were assembling the amp.
This is most likely to be the cause if you still get high SWR faults
when attempting to transmit into a dummy load.

John
AC0ZG

On 3/9/2014 7:07 PM, [hidden email] wrote:

>
> The high SWR happens even when the AL80b or Palstar tuner is not
> connected. In other words when coax from the kpxa100 goes direct to
> the K4KIO Hexx beam with nothing in between to confuse the amp except
> a barrel connector.
> Yes you can drive a larger amp with the kx3 and KXPA100. It is covered
> on page 19 of the manual in paragraph titled Keying an External
> Amplifier.
> -----Original Message-----
> From: Dr. William J. Schmidt, II <[hidden email]>
> To: rldillon <[hidden email]>; elecraft <[hidden email]>;
> KX3 <[hidden email]>
> Sent: Sun, Mar 9, 2014 8:49 pm
> Subject: RE: [Elecraft] KXPA100 SN 707 Total Frustration with this Amp
>
> Am I reading this correctly? You are driving an AL80B with the KXPA100
> being driven by the KX3? That's quite imaginative if that's correct. The
> SWR fault is coming from the AL80B input circuit not your antenna (the KXPA
> can't see the SWR on the other side of the AL80B). probably something bad
> in the input circuit of the AL80B causing the high SWR...
>
>
> Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ
>
> Owner - Operator
> Big Signal Ranch
> Staunton, Illinois
>
> email:[hidden email] <mailto:[hidden email]>
>
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rldillon

Re: [KX3] Re: KXPA100 SN 707 Total Frustration with this Amp

Thanks to all that replied either directly or via the reflector.

Today I removed the back plate and checked the coax connectors. They were installed on the proper place on the board and were fully seated.

I decided to start over from scratch and took everything apart. I tightened every screw on the back plate and reinstalled the hex nut on the rs232 jack and checked everything with my fluke. I reseated the coax connectors on the board and reinstalled the case then the back and front plates per the assembly manual.

I configured the kx3 per the Amp Manual and tested into an IFR 1600 on all HF Bands with no faults. I then added the Palstar and AL80B back in line. I keyed up the KX3 with al80b in standby and tuner bypassed. All was ok no faults on 10 - 20 Hexxbeam. I tried another antenna that required the tuner and got an error. I reduced power and fine tuned the Palstar. The SWR to fault must be sensitive in the amp since swr was under 4 before I retuned.

Everything appears to be working correctly. Again thanks to all who replied.

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