[Elecraft] K2 Transmitter and KAT2 failures

[Damon - KC5CQW]

Don, 

Actually, in CalP mode on 10m the KAT2 reports 14.2W and my external shows
8.5W.
I calibrated the KAT2 on 40m per the manual, should I set the FWD/REF pots
on a different band?
The closest setting of C55? in CALn was 006 as displayed on the K2's LCD. I
did find that the test point voltage at pin 1 on U4 was about 2.5V @ 5W
(3-4V spec). I did verify that everything was correct on and around T1. 

The good news is after two months of troubleshooting, I finally have the
radio working enough to make my first contact with it today. The other op.
was in a bit of a hurry to QSY but, he did say that the audio sounded just
fine (7.180MHz LSB with W8ERN). 

73, Damon




Don Wilhelm wrote:
> 
> Damon,
> 
> I would speculate that you have bad diodes in the KAT2 wattmeter (D1 and 
> D2), or there is some other problem with the wattmeter in the KAT2.
> 
> Try this test:
> 1) Put an external wattmeter (or other power measuring device) on the 
> output of the K2 and make certain you are connected to a good 50 ohm 
> dummy load.
> 2) Set the power to 4 or 5 watts and set the KAT2 to CAL P and press 
> TUNE - check to be certain the K2 is controlling the power output near 
> the requested level.
> 3) Evaluate the result:
> 
> If the power goes to maximum output (but displays 0.1 or 0.2 watts - 
> which is actually zero), then you have a problem with the KAT2 wattmeter 
> circuit, and it it was working before, the most likely cause is that the 
> diodes have been zapped.
> 
> OTOH, if the K2 display shows some reasonable power output, but is quite 
> different from the external wattmeter, you need to calibrate the KAT2 
> wattmeter - start with the balance adjustment, then calibrate the power 
> output and finally calibrate the SWR.  The adjustments must be done in 
> that order - if you go back to a prior adjustment, you have to re-do the 
> other adjustments.
> 
> Fact is you may have only the forward diode bad but not the refl diode - 
> that would cause a higher than normal SWR to be indicated.  Since the 
> diodes were likely damaged by a lightning static surge (yes, it can 
> happen even with an attic antenna), I would recommend replacing both of 
> them if either are suspected of causing a problem.
> 
> 73,
> Don W3FPR
> 
> Damon - KC5CQW wrote:
>> Below is some of the text that I sent to Gary. 
>> Basically, if I use the KAT2 to tune my 40m attic dipole the PA finals
>> will
>> short out. 
>> I haven't tryied to tune any other antennas because I don't want to pay
>> for
>> any more PA kits ($18.50 'ish each time I tune up).  
>> Also, CW is un-usable above 80m and no CW output on 10m (SSB and "tune"
>> yield 8.5W)
>>
>> See text below...
>>
>> 73, Damon KC5CQW
>>
>>   
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft    
> 
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
> 
> 


-----
Damon Wascom KC5CQW
Elecraft K2 #:6351
Build: 12/28/07-01/01/08


-- 
View this message in context: http://www.nabble.com/K2-Transmitter-and-KAT2-failures-tp15883353p15884384.html
Sent from the Elecraft mailing list archive at Nabble.com.