RE: [Elecraft] K2 weird problem
Gregg, If the power display does not indicate any output, it is quite possible that VRFDET is being pulled down (which will cause the K2 to develop full power output, and hence your Hi-Cur message). Check the DC voltage on the ALC THR signal (on the KSB2 board U2 pin 5. That should remain at a high level during CW transmit - I measure about 5.9 volts on a KSB2 here. If ALC THR is at zero volts or close to it, Q1 would conduct at the base/emitter junction and limit the voltage on VRFDET to about 0.7 volts (or to 0.7 volts above the level of ALC THR). I measure a voltage of about 2.5 volts on the VRFDET line at a power output level of 5 watts. If you do find ALC THR at a low level, that could be caused by either the KSB2 firmware or the U2 chip itself. Substitution for another KSB2 firmware chip would be the quickest check to determine the culprit. 73, Don W3FPR -Original Message- First I'd like to thank all of u guys fer pitching in to help me with this problem. That said, hereis an update. Power out set to 5w, CW mode. K2 works fine with no SSB brd intstalled. When SSB brd in, on CW xmit, the bar graph reads no power, the power out at the ant reads abt 10 w, high current alarm comes on when xmitting.Problem is no longer intermittent, there all the time. Have replaced (new parts) Q1, Q2 , Q3 , D1, D2 ,D3, D5, es C36 on ssb brd. Appears to be somthing related to Q1, With Q1 remmoved, rig seems to xmit OK, Tryed removing D2, but that does not help. Haven't had my mic today so can't try Peter's suggestion of measuring voltages while in ssb mode.Should I be looking on another brd for somthing feeding the ALC circuitry ? i'm going to replace C19, C38, R4,es R9 on ssb brd tonight. 73 Gregg -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.430 / Virus Database: 268.15.2/559 - Release Date: 11/30/2006 5:07 AM ___ Elecraft mailing list Post to: Elecraft@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
RE: [Elecraft] K2 weird problem
Others on the list know infinitely more than I do about how the K2-KSB2 work, but from the symptoms, I would guess that the KSB2 is loading down the VRFDET line so that the K2 thinks it isn't generating enough power. It then tries to up the power, gives the high current warning, and drops back to 10 watts. This would suggest checking the components around Q1 on the KSB2. 73 Kevin w9cf Hello agn fellow Elecrafters, I still have a problem with my K2, upon cold startup. power cont. set to 5w. CW mode. when 1st x-mit . bargraph shows almost no ind. but hi curent alarm, power out is 10+ watts( 40m) es after a minite or 2 all is backto normal with bar graph showing 5w es power out is 5w es no alarm. i followed Keith Darwins suggestion es made some rework eliminators. I narrowed the problem to when the ssb brd is plugged in. with ssb brd out, all is fine. I went thru a rebuild of the ssb board es all parts are in proper places es no cold solder joint or bridges. Problem is with ssb brd. could my problem be a faulty (intermittent) IC ??? Any sugestions appreciated. tnx, Gregg WB8LZG =- Kevin Schmidt, [EMAIL PROTECTED], http://fermi.la.asu.edu/w9cf Department of Physics Arizona State University, Tempe, AZ 85287-1504 (480) 965-8240 Fax: (480) 965-7954 ___ Elecraft mailing list Post to: Elecraft@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
RE: [Elecraft] K2 weird problem
Yes, you can just pull the SSB board, and put in two jumpers (the ends of the end jacks) and one capacitor (pins 5 and 7 of the big jack, C169 IIRC - Check the schematic. I have no ideas on the cold/High-current issue. Dan / WG4S / K2 #2456 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Gregg mulder Sent: Monday, November 27, 2006 9:47 AM To: Elecraft@mailman.qth.net Subject: [Elecraft] K2 weird problem snip Can i remove the ssb brd es install the jumpers agn without removing all of the componets on the front ? /snip ___ Elecraft mailing list Post to: Elecraft@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
RE: [Elecraft] K2 weird problem
Rework-Eliminators. Here's where they are great. Get the module header boards and build them up. Takes maybe a hour and you'll have a full set of plug-in dummy boards to replace the options you've removed. Great for trouble shooting. My K2 shows strange things after power on during TX for the first dot or two while the auto TX level circuitry figures out where it is and what it has to do. After a couple of dits on the keyer (or bug) I'm in business with the rig more-or-less producing what I'm asking for. - Keith N1AS - -Original Message- Yes, you can just pull the SSB board, and put in two jumpers (the ends of the end jacks) and one capacitor (pins 5 and 7 of the big jack, C169 IIRC - Check the schematic. -Original Message- snip Can i remove the ssb brd es install the jumpers agn without removing all of the componets on the front ? /snip ___ Elecraft mailing list Post to: Elecraft@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
