Thanks Bob, That makes me feel a bit better. I'm still going to remeasure it with a newer meter and see if the measurements check.
73, Jim KO5V -----Original Message----- >From: Bob McGraw K4TAX <[email protected]> >Sent: Nov 9, 2018 10:29 AM >To: Jim KO5V <[email protected]> >Cc: Elecraft List <[email protected]> >Subject: Re: [Elecraft] K2: KPA100 fan issue + current question > >At 13.8 volts, 11amps is about 152 watts input. 100/152 = .658 * 100 for about >66% efficiency. > >All in all , looks about right to me. AKA - I wouldn't be concerned. > > >Bob, K4TAX > > >Sent from my iPhone > >> On Nov 9, 2018, at 10:46 AM, Jim KO5V <[email protected]> wrote: >> >> Well, after checking that all of the components in the fan circuit were >> correct, I decided to follow Don's usual advice about checking my soldering, >> so I re-flowed all of their joints. None looked bad, but now the fan works >> as it should, so... >> >> I'm still curious about my 11A @ 100W measurement. I think I'll borrow a >> friend's DMM and see if I get the same voltage measurement across R1 >> (unless 11A is in the ballpark). >> >> 73, Jim KO5V >> >> -----Forwarded Message----- >>> From: Jim KO5V <[email protected]> >>> Sent: Nov 8, 2018 2:11 PM >>> To: Elecraft List <[email protected]> >>> Subject: K2: KPA100 fan issue + current question >>> >>> I just finished building and testing the KPA100 that goes with K2 #7225. >>> This kit was a rev C, and I have brought it up to the latest specs. U1 says >>> PA 1.1. >>> >>> #1: It has passed all of the tests, except it apparently has no low fan >>> speed. I have set the temperature of the heat sink using CAL tPA, after >>> measuring it with an IR thermometer, and I have set and re-set the fan >>> parameters in the secondary menu. On "nor" and on "LoHi" the fan is off. On >>> "Hi" it runs. I have tested the amp's output into my power meter at 100w, >>> but I haven't transmitted long enough to really heat anything up. >>> >>> When I first applied power to the KPA100 for the initial tests, I believe >>> the fan ran at low speed, so I have probably broken something... >>> >>> #2: When I key the amp at 100w, through the power meter, and into a dummy >>> load, I measure about .055v across R7, so that's ~11A. I expected higher >>> current. Does that seem about right? >>> >>> Any insight would be appreciated. >>> >>> Thanks in advance, & 73, >>> >>> Jim KO5V >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] >> > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
