[Elecraft] k2/100 low power

[Don Wilhelm]

Leo,

Do a quick and easy test - it does require an external wattmeter and a 
200+ watt dummy load, so if you do not have one, borrow it for a quick test.
Put the wattmeter between the KPA100 and a dummy load.  Then turn the 
power to 5 watts and do a TUNE.  Is the power indicated on the external 
wattmeter close to 5 watts or closer to 12 watts.
If it was closer to 5 watts, repeat the same test at 50 watts.  You will 
have to hold TUNE and DISPLAY at the same time.  Did the power stabilize 
near 50 watts or does it  go up to 120 watts or greater?

If during the first test, you find that the power soars to 12+ watts, do 
not bother with the 2nd test,  There is something wrong with the KPA100 
wattmeter.  The most likely failure is diodes D16 and D17, but could 
also be U5 or U6.  There is also the possibility that there is a problem 
with the scaling resistors or the 2N7000 transistors that control the 
scaling.

73,
Don W3FPR

On 3/3/2013 12:56 PM, leo wrote:
>   My k2/100 has been working good for about 12 month's. The only problem was
> when I put the power over 90W I would get a Hi Cur warning so I would keep
> it down to 90W, might have been a mistake not to fix that. Now everything
> over about 20W the radio will drop down to about 20 watts. I'm using a dummy
> load and cal cur is at 3.5 .The problem is on all bands.
>   Looking through the E-Mail's I see that diodes D16,D17 1N5711 in the amp
> might be bad any thoughts will be appreciated. Thanks  Leo
>   kg6wni at yahoo.com
>
>
>
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