[Elecraft] K2 Problems

[Don Wilhelm]

Brent,

In cases of lightning damage to the KPA100, I normally just replace all 
the active devices (transistors, diodes and ICs) on the premise that if 
not damaged, they have been stressed and will fail later - I do not 
normally replace the KPA100 PA transistors because they are quite 
hardy..  The KAT100 does not usually endure damage other than the diodes 
in the wattmeter and usually the firmware IC, but you can't take my 
"usual" observations to heart with lightning damage. Most anything is 
suspect, so check it all out.

Look at the boards - If there is evidence of charring or burning, that 
area will have to be cleared of carbon and any damaged PC traces 
replaced with wire repairs.

What I am saying is that it is less expensive and easier to assume that 
all active devices have been damaged and arbitrarily replace then than 
it is to try to debug exactly the failing component and then endure the 
frustration of an additional failure a few weeks later when a stressed 
component fails.  Replacing all the ICs in the KPA100 and KAT100 is not 
really that expensive when compared with the alternative.

73,
Don W3FPR

On 8/29/2012 6:48 PM, Brent Sutphin wrote:
> I now have the basic K2 working as it should after replacing the TX finial
> and bias transistors. Now to move on to the KPA100.
>
> Brent
> ----- Original Message -----
> From: "Brent Sutphin" <bsutphin at triad.rr.com>
> To: <elecraft at mailman.qth.net>
> Sent: Thursday, August 23, 2012 9:27 PM
> Subject: [Elecraft] K2 Problems
>
>
>> The symptoms I explained earlier were after an electrical storm
>> that also took out my cable modem and wireless router.  The K2 was
>> connected
>> to its antenna but was turned off at the time.  It also had the KPA100 and
>> KAT100 installed.  I decided to remove the KPA100 and KAT100 to see if I
>> still had the problem with the basic K2.  I wanted to see if the high
>> current warning was
>> still there.  The high current warning did not come on but the power
>> transistors became very hot very quickly. I was not transmitting. That led
>> me to believe
>> that the power transistors were defective. There very well could be
>> problems
>> with the KPA100 as well.  Now I'm not so sure.
>>
>> Brent
>> WB4X
>>
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