[Elecraft] KPA-1500 input too high

[rocketnj at gmail.com]

Don, first thing I did. Radio is indeed sending 20 watts on 80 meters. Is a Flex 6600, not capable of 191 watts the amp said it was seeing.

The 3 watt, 3k Ohm resistor on the filter board is discolored and one side desoldered itself. This provides RF to the onboard frequency counter. This is the second time in three months that resistor has been an issue. Last time it was discolored and fell off the board (mounted upside down).

This time it appears to be more involved than just the 3 watt resistor.

Dave wo2x


-----Original Message-----
From: Don Wilhelm <donwilh at embarqmail.com> 
Sent: Saturday, April 27, 2019 6:08 PM
To: rocketnj at gmail.com; elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA-1500 input too high

What are you using to drive the KPA1500?

Connect the driving transceiver to an external wattmeter, and then to a dummy load.  Do a KeyDown in CW mode and see what the actual power output is shown on the external wattmeter.

My thinking is that your driving transceiver has lost its ability to control the power output.  Do the test with an external wattmeter and a dummy load rather than depending on the power indications from either the KPA1500 or the driving transceiver.  In other words, check each piece of gear one piece at a time.

73,
Don W3FPR

On 4/27/2019 5:48 PM, rocketnj at gmail.com wrote:
> Hi All,
> 
>   
> 
> KPA-1500 s/n 423
> 
>   
> 
> Operating 80 meter SSB running 20 watts drive with tuner engaged for about
> 1240 watts out PEP. Remote app shows maximum power handling of 1620 watts.
> 
> Out of nowhere I got an input power too high alarm @ 191 watts! The radio is
> capable of 100 watts out max and verified is set to 20 watts.
> 
>   
> 
> Set tune power to 10 watts.
> 
> Meter in amp during standby reads 10 watts.
> 
> Switch to operate and immediately get input power too high alarm @ 91 watts.
> 
>   
> 
> Switch to 20 meters (resonant antenna). No issue - 10 watts tune is
> approximately 400 watts out with no error.
> 
>   
> 
> Any ideas?
> 
>   
> 
> Dave wo2x
> 
>   
> 
>   
> 
>   
> 
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