Re: QRO - KPA500 Failure

Posted by Rick Bates, NK7I on Feb 06, 2020; 9:07pm
URL: http://elecraft.85.s1.nabble.com/QRO-KPA500-Failure-tp7658244p7658248.html

Since the SWR is still nominal into the amp (as shown on your radio),
it's not likely the tuned input circuits (which is confirmed from no
output on all bands).

This points to the high power module.  Running low output power from it,
is far less efficient than pushing it hard (compare wattages consumed to
RF watts output delivered at different output levels); which may have
stressed the finals.  Ideally you run the previous stages at
low-moderate power for lower IMD, then punch it up with the amp.

The "HIGH SWR" fault you saw is then very likely the final signing QRT
SK.  You can confirm that with Elecraft wizards.

That module isn't hard to swap out, but it would be best (slightly more
costly) for the entire amp to visit it's parents, so that other updates
that may not have been done, can be done. Many of them, really matter.

While also not cheap in shipping and insurance (ask me how I know?) that
is often the better choice.

Rick, NK7I

On 2/6/2020 12:54 PM, Michael Walker wrote:

> Amps making noises like that usually mean you have to take the covers off.
>
> They are easy enough to repair if you are so inclined.  If not, then you
> will need to contact Elecraft support and odds are you will have to send it
> home for a Spa day.
>
> Mike va3mw
>
>
> On Thu, Feb 6, 2020 at 3:35 PM Jim Brown <[hidden email]> wrote:
>
>> On 2/6/2020 12:15 PM, Jim Mullen wrote:
>>> Any pointers of where to start looking?
>> 1) What SWR does the rig see with the amp off?
>> 2) Make notes of any error messages given by the KPA500 display.
>> 3) Call Elecraft Support
>>
>> 73, Jim K9YC
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