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KPA1500 LOW GAIN FAULT

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Ed Gilliland

KPA1500 LOW GAIN FAULT

My KPA1500 is faulting with a low gain alarm ration 6. This is with 23
watts input 160-10 meters. Any advice?

Thanks, Ed W5TM

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Vic Rosenthal

Re: KPA1500 LOW GAIN FAULT

The first thing to do with any amplifier failure is to try it with a dummy load. If the problem still occurs, you can rule out SWR or RF feedback problems. It doesn’t seem like any of the above if it occurs on all bands, but it’s easy and a good start to a systematic diagnosis.

Victor 4X6GP

> On 30 Apr 2019, at 5:35, Ed gilliland <[hidden email]> wrote:
>
> My KPA1500 is faulting with a low gain alarm ration 6. This is with 23 watts input 160-10 meters. Any advice?
>
> Thanks, Ed W5TM
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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Eric Swartz - WA6HHQ

Re: KPA1500 LOW GAIN FAULT

Administrator

In reply to this post by Ed Gilliland

Hi Ed,

Please email [hidden email] and they will dig into it immediately to help
you resolve the problem.

If you can use the KPA1500 utility to download the 1500's config file and attach
it to that email that will also be helpful. (They can walk you through that
procedure if needed.) that file includes both the amps full configuration and
its detailed fault log.)

73,
Eric
/elecraft.com/

On 4/29/2019 7:35 PM, Ed gilliland wrote:

> My KPA1500 is faulting with a low gain alarm ration 6. This is with 23 watts
> input 160-10 meters. Any advice?
>
> Thanks, Ed W5TM
>
> ______________________________________________________________
> 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

Ed Gilliland

Re: KPA1500 LOW GAIN FAULT

In reply to this post by Vic Rosenthal

Hi Vic, thanks.

That's the first thing I tried, should have included my checks in the
first message. Here is what I've done so far.

Put a dummy load on the antenna 1 port

Confirmed that the amp was on antenna port one

Checked the SWR between the K3 and the amp 1.1 without the K3 tuner

Re-seated all the cables on the KPA1500 rear panel

Tried the amp again and it works. I have no idea what cable fixed the
problem. I am using a back to back cable between the K3 and the KPA1500
AUX ports but it's been installed for months and I've experienced no
problems. We'll find out in tomorrow's CWT. I think I'll run the amp
at 900 watts until I gain confidence.

WOW! WHAT A RELIEF!

Ed

On 4/30/2019 01:21, Vic Rosenthal wrote:

> The first thing to do with any amplifier failure is to try it with a dummy load. If the problem still occurs, you can rule out SWR or RF feedback problems. It doesn’t seem like any of the above if it occurs on all bands, but it’s easy and a good start to a systematic diagnosis.
>
> Victor 4X6GP
>
>> On 30 Apr 2019, at 5:35, Ed gilliland <[hidden email]> wrote:
>>
>> My KPA1500 is faulting with a low gain alarm ration 6. This is with 23 watts input 160-10 meters. Any advice?
>>
>> Thanks, Ed W5TM
>>
>> ______________________________________________________________
>> 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

Vic Rosenthal

Re: KPA1500 LOW GAIN FAULT

Great, there is nothing that is more fun than an intermittent problem!
But there could have been dirt on one of the pins of the cables, and it
may never happen again.
Maybe Elecraft engineers can give you some hints.
See you in the CWTs tomorrow!

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

On 30/04/2019 20:55, Ed gilliland wrote:

> Hi Vic, thanks.
>
> That's the first thing I tried, should have included my checks in the
> first message. Here is what I've done so far.
>
> Put a dummy load on the antenna 1 port
>
> Confirmed that the amp was on antenna port one
>
> Checked the SWR between the K3 and the amp 1.1 without the K3 tuner
>
> Re-seated all the cables on the KPA1500 rear panel
>
> Tried the amp again and it works. I have no idea what cable fixed
> the problem. I am using a back to back cable between the K3 and the
> KPA1500 AUX ports but it's been installed for months and I've
> experienced no problems. We'll find out in tomorrow's CWT. I think
> I'll run the amp at 900 watts until I gain confidence.
>
> WOW! WHAT A RELIEF!
>
> Ed
>
>
>
> On 4/30/2019 01:21, Vic Rosenthal wrote:
>> The first thing to do with any amplifier failure is to try it with
>> a dummy load. If the problem still occurs, you can rule out SWR or
>> RF feedback problems. It doesn’t seem like any of the above if it
>> occurs on all bands, but it’s easy and a good start to a systematic
>> diagnosis.
>>
>> Victor 4X6GP
>>
>>> On 30 Apr 2019, at 5:35, Ed gilliland <[hidden email]> wrote:
>>>
>>> My KPA1500 is faulting with a low gain alarm ration 6. This is
>>> with 23 watts input 160-10 meters. Any advice?
>>>
>>> Thanks, Ed W5TM

Bob McGraw - K4TAX

Re: KPA1500 LOW GAIN FAULT

I've found that hams are notorious for plugging in a multi pin
connector and not securing the connector to be tight with the provided
thumb screws. The "I'll do it later, but I've got to get it on the air
now" seems to always take precedence . The connectors will wiggle
and back out, often leaving an intermittent connection.

Likewise with PL-259 connectors. Finger tight is simply not good enough
for a reliable RF connection. I use a pair of 4" Channel lock pliers to
snug the PL-259 connectors. And I solved many RFI issues for others
just by tightening the PL-259's in the path.

73

Bob, K4TAX

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Gwen Patton

Re: KPA1500 LOW GAIN FAULT

I started using a corrosion-inhibiting lube on my PL-259s, and religiously
sealing them with Coax-Seal. I tighten them very tightly as well. Since I
started doing that, I have no odd failures or intermittent connections in
my feedlines.

73,
Gwen, NG3P

On Tue, Apr 30, 2019 at 5:13 PM Bob McGraw K4TAX <[hidden email]>
wrote:

> I've found that hams are notorious for plugging in a multi pin
> connector and not securing the connector to be tight with the provided
> thumb screws. The "I'll do it later, but I've got to get it on the air
> now" seems to always take precedence . The connectors will wiggle
> and back out, often leaving an intermittent connection.
>
> Likewise with PL-259 connectors. Finger tight is simply not good enough
> for a reliable RF connection. I use a pair of 4" Channel lock pliers to
> snug the PL-259 connectors. And I solved many RFI issues for others
> just by tightening the PL-259's in the path.
>
> 73
>
> Bob, K4TAX
>
>
>
> ______________________________________________________________
> 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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> Please help support this email list: http://www.qsl.net/donate.html

--

-+-+-+-+-
Jenny Everywhere's Infinite: Quark Time
http://quarktime.net
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Bob McGraw - K4TAX

Re: KPA1500 LOW GAIN FAULT

A good approach for those PL-259 connectors outside or exposed to the
weather. For those inside, that's a might bit aggressive. I just
prefer to snug them tight, a bit more than hand tight, using some small
channel lock pliers.

73

Bob, K4TAX

On 4/30/2019 5:54 PM, Gwen Patton wrote:
> I started using a corrosion-inhibiting lube on my PL-259s, and religiously
> sealing them with Coax-Seal. I tighten them very tightly as well. Since I
> started doing that, I have no odd failures or intermittent connections in
> my feedlines.
>
> 73,
> Gwen, NG3P
>

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Gwen Patton

Re: KPA1500 LOW GAIN FAULT

I don't know if you're talking about what I do, Bob, but I guess I should
have said that I do that with the outdoor connectors, where they might
encounter weather. Indoor connectors are just snugged down tight enough
that they don't wiggle loose, since I disconnect them whenever lightning is
in the area.

Gwen, NG3P

On Tue, Apr 30, 2019 at 7:18 PM Bob McGraw K4TAX <[hidden email]>
wrote:

> A good approach for those PL-259 connectors outside or exposed to the
> weather. For those inside, that's a might bit aggressive. I just
> prefer to snug them tight, a bit more than hand tight, using some small
> channel lock pliers.
>
> 73
>
> Bob, K4TAX
>
> On 4/30/2019 5:54 PM, Gwen Patton wrote:
> > I started using a corrosion-inhibiting lube on my PL-259s, and
> religiously
> > sealing them with Coax-Seal. I tighten them very tightly as well. Since I
> > started doing that, I have no odd failures or intermittent connections in
> > my feedlines.
> >
> > 73,
> > Gwen, NG3P
> >
>
> ______________________________________________________________
> 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

Elecraft mailing list

Re: KPA1500 LOW GAIN FAULT

Just an interesting aside.

Last night at the radio club meeting the guys were checking out a Yaesu controller box that will operate the az/el rotor for an ARISS contact this June from our local library. No one could get it to work until someone brought in another connecting cable (I think it was a db 9 pin USB cable). Voila! It works.

Just lurking on the Elecraft site I see many problems are connected to the incorrect cable or a faulty cable.

Take away: don’t throw away those cables you have been collecting over the years. I have fixed a few problems over the years by trying a different cable.

David J. Wilcox K8WPE’s iPad

> On Apr 30, 2019, at 7:35 PM, Gwen Patton <[hidden email]> wrote:
>
> I don't know if you're talking about what I do, Bob, but I guess I should
> have said that I do that with the outdoor connectors, where they might
> encounter weather. Indoor connectors are just snugged down tight enough
> that they don't wiggle loose, since I disconnect them whenever lightning is
> in the area.
>
> Gwen, NG3P
>
> On Tue, Apr 30, 2019 at 7:18 PM Bob McGraw K4TAX <[hidden email]>
> wrote:
>
>> A good approach for those PL-259 connectors outside or exposed to the
>> weather. For those inside, that's a might bit aggressive. I just
>> prefer to snug them tight, a bit more than hand tight, using some small
>> channel lock pliers.
>>
>> 73
>>
>> Bob, K4TAX
>>
>>> On 4/30/2019 5:54 PM, Gwen Patton wrote:
>>> I started using a corrosion-inhibiting lube on my PL-259s, and
>> religiously
>>> sealing them with Coax-Seal. I tighten them very tightly as well. Since I
>>> started doing that, I have no odd failures or intermittent connections in
>>> my feedlines.
>>>
>>> 73,
>>> Gwen, NG3P
>>>
>>
>> ______________________________________________________________
>> 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
>
>
>
> --
>
> -+-+-+-+-
> Jenny Everywhere's Infinite: Quark Time
> http://quarktime.net
> ______________________________________________________________
> 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