Hi Gary, Just to let you know: I swapped out the power supply and it cleared up the 160M problem. Thanks again for the stellar support! Julius n2wn
--- Gary Surrency <[EMAIL PROTECTED]> wrote: > OK Julius. I hope you find that is all it is. > > Good luck! > > -- > 73, Gary AB7MY > ========= > [EMAIL PROTECTED] > Elecraft Technical Support > > > > > -----Original Message----- > From: J F [mailto:[EMAIL PROTECTED] > Sent: Monday, February 07, 2005 9:39 AM > To: Gary Surrency > Subject: Re: N2WN: RE: 160M problem > > > Gary, > Based on this list, I'm going to try #10. I do > notice > that the Power Supply seems to drop almost a volt in > key down. So I suspect it at this junction. I do > have > another PS, so I'll try that first. > Thanks again! > Julius > n2wn > > --- Gary Surrency <[EMAIL PROTECTED]> wrote: > > > See what the TX current demand is with the power > to > > the KPA100 turned off, > > so just the K2's QRP output is produced. > > > > Then try the K2 on 160m at max power without the > > KPA100 connected at all. > > > > If the current demand is too high, it may be: > > > > 1) Wrong turns on the toroids in the lowpass > filters > > (LPF) for the K2 or > > KPA100. > > 2) Wrong or missing caps in the LPF for the K2 or > > KPA100. > > 3) Poor connections in these areas. Make sure all > > toroids are well tinned > > and soldered. > > 4) Wrong freq. being produced, such as a kit I > just > > repaired that had no C75 > > installed in the VCO circuit for the K2. Check > that > > the freq. at TP1 is as > > expected in the VCO Table in the K2 manual. The > > freq. shown is with the VFO > > at the bottom edge of the band. Check that the VCO > > voltage is between 1.5 > > and 7.5VDC at 1800 and 2000kHz. > > 5) Wrong turns on the PA output transformer of the > > K2 or KPA100. > > 6) Wrong caps in the PA input circuit between T1 > and > > T2 on the KPA100. > > 7) Lack of enough t-r switch reverse bias, > resulting > > in poor t-r switch > > isolation and the result is oscillation of the > > KPA100 PA stage. The left > > side of the resistors at R11, R12 (nearest R14) > must > > be more than 100VDC > > when in TX, and the higher the better. > > 8) Apply the last two items of the attached KPA100 > > errata if the test in #7 > > above is not correct, or if your kit does not > > already have these changes. > > 9) Wrong toroid core used for SWR sensor T4. It > must > > be the larger FT50-37 > > gray core. > > 10) Sometimes the power supply is the problem, and > > it may be outputting a > > poorly regulated voltage when the rig is operating > > at high power on some > > bands. A fellow in Holland last week had this > > problem. Try another power > > supply or 12V auto battery if this is suspected. > > > > -- > > 73, Gary AB7MY > > ========= > > [EMAIL PROTECTED] > > Elecraft Technical Support > > > > > > > > > > -----Original Message----- > > From: J F [mailto:[EMAIL PROTECTED] > > Sent: Monday, February 07, 2005 7:13 AM > > To: Gary Surrency > > Subject: Re: N2WN: RE: 160M problem > > > > > > Hi Gary, > > I probably did not make the 30 seconds. I don't > > recall > > that being the same on the other bands, but I > > probably > > wasn't looking either. > > > > Cal Cur is set to 3.5. The only band (I checked > this > > weekend) that I get the high current warning on is > > 160M. It looks like I draw 22 Amps with the pot > > cranked, but I can back it off (almost 35%) and it > > works fine. It does the same thing into a dummy > > load. > > > > This was working fine previously. I'm not quite > sure > > what event caused the change. I guess what baffles > > me > > most, is that it is band specific. I would have > > expected the problem to be in the circuitry you > > mention, but accross all the bands... Curious eh? > > > > 73, > > Julius > > n2wn > > > > --- Gary Surrency <[EMAIL PROTECTED]> wrote: > > > > > Julius, > > > > > > The rig does not remember a frequency when it is > > > turned off, unless 30 > > > seconds have elapsed or the mode or band has > been > > > changed. This saves write > > > cycles to the 25LC320 EEPROM on the control > board. > > > See page 94 of the K2 > > > manual, "Backup Timer". > > > > > > CAL CUR should be set to 3.5A in the K2 menu to > > > avoid unnecessary HI CUR > > > warnings. If this occurs only when the K2 is > > > operating without the KPA100 > > > 100w option, HI CUR may occur if the RF output > > > exceeds 10w, the antenna load > > > Z is not close to 50 ohms resistive, or if there > > is > > > an error on the 160m > > > option such as the wrong number of turns on the > > > lowpass filter toroids. > > > Damage to U6 on the KPA100 can also prevent the > > > needed VRFDET signal from > > > the SWR detector to the K2 MCU VRFDET pin 2, as > > can accidental > > > incorrect connection of the ribbon or RS232 > > cables. > > > > > > If HI CUR occurs with the KPA100 installed and > > > operating at 100w, then there > > > could be a problem with the lowpass filters on > it, > > > such as the wrong turns > > > count, wrong caps, or missing caps. > > > > > > Also: > > > > > > If the FWD and REFL cal pots on the KPA100 are > not > > > set accurately, it can > > > cause too high or too low RF output. Most > KPA100s > > > have 41-44K from the wiper > > > of the cal pots at R26 and R27 to ground when > they > > > are set correctly. This > > > is more easily measured at the LM358 at U5 pin 5 > > > (FWD, R26), and U5 pin 3 > > > (REFL, R27). > > > > > > The 1N5711 diodes at D16, D17 in the SWR > detector > > on > > > the KPA100 can > > > definitely be damaged by nearby storms. Try > > > operating the rig on all bands > > > with a dummy load to see if the problem > continues. > > > Use care to not damage > > > the rig from excessive RF output or current. > > > > === message truncated === _______________________________________________ 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