KPA500 clicks and thermal design

[ANDY DURBIN]

I find the "clicks" my KPA500 makes as its temperature changes to be quite distracting.  Part of the problem is that I'm chasing a problem where the KPA500 changes band spuriously and the thermal clicks sound too much like the relays re-configuring the LPF.


To what extend does the thermal design require conduction between the PA heat sink and the case metalwork?  Would the thermal management be compromised if very thin mylar strips were placed between the heat sink and the case side panel , case rear panel, or Z bracket?


Any other proven techniques for eliminating the thermal expansion/contraction clicks?  (I know the manual says this is normal so no need to tell me that).


73,

Andy k3wyc
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[Buck]

Make sure the transformer is on straight and secured.  Mine clicked for a
while but has since stopped.

On Sat, Apr 21, 2018, 1:35 PM ANDY DURBIN <[hidden email]> wrote:

> I find the "clicks" my KPA500 makes as its temperature changes to be quite
> distracting.  Part of the problem is that I'm chasing a problem where the
> KPA500 changes band spuriously and the thermal clicks sound too much like
> the relays re-configuring the LPF.
>
>
> To what extend does the thermal design require conduction between the PA
> heat sink and the case metalwork?  Would the thermal management be
> compromised if very thin mylar strips were placed between the heat sink and
> the case side panel , case rear panel, or Z bracket?
>
>
> Any other proven techniques for eliminating the thermal
> expansion/contraction clicks?  (I know the manual says this is normal so no
> need to tell me that).
>
>
> 73,
>
> 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
> Message delivered to [hidden email]
>

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[Michael Blake]

My KPA500 clicking has pretty much stopped as well.  The transformer noise has also reduced in amplitude over time (about 3 months).

Michael Blake
[hidden email]

On Apr 21, 2018, at 03:26 PM, Craig Buck <[hidden email]> wrote:

Make sure the transformer is on straight and secured. Mine clicked for a
while but has since stopped.

On Sat, Apr 21, 2018, 1:35 PM ANDY DURBIN <[hidden email]> wrote:

I find the "clicks" my KPA500 makes as its temperature changes to be quite
distracting. Part of the problem is that I'm chasing a problem where the
KPA500 changes band spuriously and the thermal clicks sound too much like
the relays re-configuring the LPF.


To what extend does the thermal design require conduction between the PA
heat sink and the case metalwork? Would the thermal management be
compromised if very thin mylar strips were placed between the heat sink and
the case side panel , case rear panel, or Z bracket?


Any other proven techniques for eliminating the thermal
expansion/contraction clicks? (I know the manual says this is normal so no
need to tell me that).


73,

Andy k3wyc
______________________________________________________________
Elecraft mailing list
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Message delivered to [hidden email]

______________________________________________________________
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