http://elecraft.85.s1.nabble.com/KPA1500-Thermal-problems-tp7656375p7656385.html
I operated the contest with over 1200 contacts. I never saw temps over
80c. I too have a low serial number but have installed all the firmware
updates. Only on 40m did I hear the fan speed get to a very high speed. I
> Thank you for the information. RTTY contests are the acid test of an
> amp....
>
> On Mon, Nov 11, 2019 at 8:35 AM Jim Miller <
[hidden email]> wrote:
>
> > It trips off at 105C.
> >
> > It starts warning with a yellow indication at 100c
> >
> > Power reduced to 1kw helped slow the rate of temperature increase but
> > still required a cold room and max fan speed at the beginning to contain
> > it. It never stopped climbing.
> >
> > Jim ab3cv
> >
> > On Mon, Nov 11, 2019 at 9:32 AM Fred Massey <
[hidden email]> wrote:
> >
> >> What output power did that reduce too ultimately, is 105c the design
> >> temp limit?
> >>
> >> On Mon, Nov 11, 2019 at 8:30 AM Jim Miller <
[hidden email]> wrote:
> >>
> >>> " I rode the drive power downward as the power increased to stay below
> >>> the
> >>> trip point of 105c."
> >>>
> >>> Should have been "as the temperature increased"
> >>>
> >>> jim ab3cv
> >>>
> >>> On Mon, Nov 11, 2019 at 9:03 AM Jim Miller <
[hidden email]> wrote:
> >>>
> >>> > I participated in the WAE RTTY contest this past weekend and was
> having
> >>> > problems with thermal tripping.
> >>> >
> >>> > I have resonant antennas for 80, 40 and 20m and had SWR between 1:1
> and
> >>> > 1.2:1, power nominally set between 1400-1500w.
> >>> >
> >>> > I found that I couldn't repeatedly CQ without temperature creeping up
> >>> so I
> >>> > paused to around 50% duty cycle to stop that.
> >>> >
> >>> > However when sending QTC which amount to about 200 characters the
> >>> > temperature would rapidly increase and eventually thermal trip.
> >>> >
> >>> > I took several actions to try to compensate:
> >>> >
> >>> > I opened the shack windows and bundled up. Shack then stayed at 60f
> or
> >>> > below.
> >>> > I immediately manually cranked the fan speed to max (5) when started
> to
> >>> > send QTCs.
> >>> > I rode the drive power downward as the power increased to stay below
> >>> the
> >>> > trip point of 105c.
> >>> >
> >>> > Upon taking all these actions I was able to eventually send the QTC
> >>> > packets but it was unnerving and unexpected.
> >>> >
> >>> > This is a low serial number KPA1500 but with latest production
> >>> firmware.
> >>> >
> >>> > What have others seen?
> >>> >
> >>> > 73
> >>> >
> >>> > jim ab3cv
> >>> >
> >>> ______________________________________________________________
> >>> 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> >>> Message delivered to
[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> Message delivered to
[hidden email]
>