KPA-1500 failed!

Sorry to hear this happen Peter, especially during a contes. LDMOS devices
are suppose to be pretty tough and the KPA1500 is not pushing their limits.
There are videos of a different LDMOS showing it to be indestructible:
https://www.youtube.com/watch?v=8ziYqjMQGEQ  Is the KPA1500 cooling and heat
sink adequate?  Personally if I owned this amp I would leave the fan on at a
tolerable speed 100% of the time.  Did you use the amp during the RTTY
contest last weekend?

John KK9A


Paul Baldock wrote:

It sounds like one of the output devices have failed. Half power out
is usually the indicator. A number here have reported this happening.
It would be nice to know why this problem is occurring and if
Elecraft are working on a fix.

- Paul

>
>On 2/16/2019 7:28 AM, lists at w2irt.net wrote:
> > I was operating in the ARRL-CW contest this morning and on 20m, with a
> > 1.2:1 SWR on the Yagi, all of a sudden I saw my power drop to about
> > 450-500W with about 40W in. Worked a few stations but not as easily as
> > when I turned everything on this morning. Switched over to phone
> and made a few contacts.
> > Audio is fine barefoot with 100W out of the K3s-which suffered blown
> > finals itself during CQWW SSB last fall, but with the amp in I got
> > reports that my audio was badly distorted.
> >
> > Before I send it in, is there anything I should look at or any
> > diagnostics I can easily perform? For the cost of this, I'd have
> > thought protection would have kicked in to prevent anything untoward
> > from happening. I'm in complete disbelief, to be honest.
> >
> > ---------------------------------------------
> > 73 and Good DX
> > Peter, W2IRT

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[Peter W2IRT]

I don't contest in RTTY (I don't use that mode other than for Dxpeditions)
and rarely even do FT8. I mostly operate CW and a bit of SSB and that's it.

I have no idea why it would fail. I did have some issues in the past with
antennas going stupid on me or the HF-Auto tuner failing to match when it
was supposed to, but those always hard-faulted instantly. I never attempted
to push RF through more than about a 2:1 without a tuner, and for CW, all my
antennas are resonant on the bottom of all the bands. That it happened on 20
where I'm about 1.2:1 is very strange.

 - pjd

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of [hidden email]
Sent: Saturday, February 16, 2019 12:35 PM
To: [hidden email]
Subject: [Elecraft] KPA-1500 failed!

Sorry to hear this happen Peter, especially during a contes. LDMOS devices
are suppose to be pretty tough and the KPA1500 is not pushing their limits.
There are videos of a different LDMOS showing it to be indestructible:
https://www.youtube.com/watch?v=8ziYqjMQGEQ  Is the KPA1500 cooling and heat
sink adequate?  Personally if I owned this amp I would leave the fan on at a
tolerable speed 100% of the time.  Did you use the amp during the RTTY
contest last weekend?

John KK9A


Paul Baldock wrote:

It sounds like one of the output devices have failed. Half power out is
usually the indicator. A number here have reported this happening.
It would be nice to know why this problem is occurring and if Elecraft are
working on a fix.

- Paul

>
>On 2/16/2019 7:28 AM, lists at w2irt.net wrote:
> > I was operating in the ARRL-CW contest this morning and on 20m, with
> > a
> > 1.2:1 SWR on the Yagi, all of a sudden I saw my power drop to about
> > 450-500W with about 40W in. Worked a few stations but not as easily
> > as when I turned everything on this morning. Switched over to phone
> and made a few contacts.
> > Audio is fine barefoot with 100W out of the K3s-which suffered blown
> > finals itself during CQWW SSB last fall, but with the amp in I got
> > reports that my audio was badly distorted.
> >
> > Before I send it in, is there anything I should look at or any
> > diagnostics I can easily perform? For the cost of this, I'd have
> > thought protection would have kicked in to prevent anything untoward
> > from happening. I'm in complete disbelief, to be honest.
> >
> > ---------------------------------------------
> > 73 and Good DX
> > Peter, W2IRT

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Please help support this email list: http://www.qsl.net/donate.html Message
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