KPA500 PA transistor screws

[ANDY DURBIN]

From "KPA100 failure" topic -

"Thirdly, were the PA transistors tight? If not, the PA transistors will heat the board around the transistors and not be thermally  coupled to the heatsink.  Are the thermal pads properly in place? After initial assembly (and anytime afterwards if the thermal pads are changed) you must re-tighten the screws after about 10 hours of operation at high power."

Does the KPA500 need similar attention after the first 10 hours of use?   How long is the factory burn-in of KPA500 PA modules and is the security of the mounting screws checked after burn-in?

Andy, k3wyc
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[Don Wilhelm]

Andy,

No, the KPA500 is a different design than the KPA100.

73,
Don W3FPR

On 1/5/2019 5:02 PM, Andy Durbin wrote:

>>From "KPA100 failure" topic -
>
> "Thirdly, were the PA transistors tight? If not, the PA transistors will heat the board around the transistors and not be thermally  coupled to the heatsink.  Are the thermal pads properly in place? After initial assembly (and anytime afterwards if the thermal pads are changed) you must re-tighten the screws after about 10 hours of operation at high power."
>
> Does the KPA500 need similar attention after the first 10 hours of use?   How long is the factory burn-in of KPA500 PA modules and is the security of the mounting screws checked after burn-in?
>
> Andy, k3wyc
> ______________________________________________________________
> 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
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>

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