[Elecraft] KNB2 Installed, but...

[Don Wilhelm]

  Larry,

You probably have some slivers of aluminum embedded in the thermal pads.
Unless you have some good thermal conductive material laying around, I 
would request replacement thermal pads from parts at elecraft.com.

BTW - when you replace the hardware, do not use the internal toothed 
lockwashers - they can dig out bits of aluminum and cause just the 
problem you are having.  Substitute split lockwashers.  You may have 
enough left over from the option installation, normally a few extras are 
included.

73,
Don W3FPR

On 1/23/2011 8:43 PM, L Kendall wrote:
> I built the KNB2 board and installed it today.
>
> No problems with that, but it occurred to me while the 100 Watt board
> was removed to check the TO220 packaged Q7 and Q8 on the RF board for
> any electrical continuity to the heat sink .
>
> I have to back those 4-40 nuts out to barely finger tight or it measures
> short to ground.
>
> Is there a suitable substitute material I can use for those adhesive
> insulating pads between the transistor and the grounded heat sink?
> Elecraft p/n in the manual is E700002.
>
> Thanks,
> Larry
> K5END
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>