+++++++++++++++++++++ Date: Tue, 14 May 2002 14:24:05 -0500 To: "Chuck Roedel" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] soldering iron recommendations Chuck: Got a soldering GUN? Use it! The idea is to not only find a nice HOT iron, but preferably one with a decently wide tip... say 0.2" to 0.25" and a moderate amount of mass to be able to supply a decent amount of heat in one pass. If you happen to have a LARGE WTCPT 700 deg. tip, you may also be able to make that work. Being really HOT's not necessarily as important as having the mass so you will be able to SUPPLY what heat you do have (c. 700 deg.) to the fairly large PC board land, and for a slightly extended amount of time... maybe 5-10 seconds. Tom N0SS At 10:14 AM 5/14/02, you wrote: >Hello to everyone, > >I used a Weller WTCPT for soldering my K2 and accessories .I see in the >KPA100 manual the final transistors must be soldered in with a higher >wattage iron than what's used for assembling the rest of the unit. >What would be a good iron to purchase for this task? +++++++++++++++++++++ Date: Tue, 14 May 2002 18:39:40 -0500 To: "elecraft L-serve" From: "Timothy A. Raymer" Subject: Re: [Elecraft] soldering iron recommendations Chuck, We just had a similiar discussion on the Field test forum. If you have a PTD-7 tip for your weller, you should be OK. We also discussed Weller W60P irons, as well as good old Weller 200/260 guns that you can get at the hardware store. If there is any update, I will let you know here. Tim Raymer K2 #1383 At 11:14 05/14/2002 -0400, Chuck Roedel wrote: >Hello to everyone, > >I used a Weller WTCPT for soldering my K2 and accessories .I see in the >KPA100 manual the final transistors must be soldered in with a higher >wattage iron than what's used for assembling the rest of the unit. >What would be a good iron to purchase for this task? Timothy A. Raymer Missouri Department of Health and Senior Services ++++++++++++++++++++++ Date: Thu, 13 Jun 2002 13:48:14 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 detailed assy pics I've added a link to PA3CEV's detailed KPA100 assembly pictures on our Builders Resource Page at www.elecraft.com The direct link to his page is: http://www.qsl.net/pa3cev/KPA100/ 73, Eric WA6HHQ +++++++++++++++++++++++ From: "Don Brown" To: "Dave Gingrich K9DC" , "Elecraft" Subject: Re: [Elecraft] K2/100 errata Date: Sun, 16 Jun 2002 08:35:38 -0500 Hi The 1200 pf cap at C83 will work fine. It was the original value at the s= tart of the field test.. However it was discovered reducing it to 1000 pf= improved the efficiency on 10 meters by reducing the current draw at 100= watts with no other ill effects. 1000 pf is now the recommended value fo= r C83. Don Brown KD5NDB =20 ----- Original Message ----- From: Dave Gingrich K9DC Sent: Sunday, June 16, 2002 7:25 AM To: elecraft at mailman.qth.net Subject: [Elecraft] K2/100 errata The errata for the K2/100, item # 2 advises us of a component value chang= e for capacitor C83 and suggests changing it in the parts list. Unfortunately, that paragragh does not suggest making any note on page 36 where that part is installed. Since components of both values are supplied, it is quite likely you (lik= e me) will install the original value cap, especially if your parts invento= ry process is simmilar to mine, i.e. non-existent. I have no idea what effect the decreased value of C83 is, but my radio seems to work fine with C83 at 1200. Don't know whether I will change it = or not. Dave Gingrich, K9DC - Indianapolis, Indiana USA K2 #2211, K1 #931, QRP-L #2376, ARS #1109, FPQRP #389, IRLP #473, k9dc.ampr.org, CCIE #6748 +++++++++++++++++++ Date: Mon, 17 Jun 2002 08:48:03 -0500 To: elecraft at mailman.qth.net From: Dave Gingrich K9DC Subject: [Elecraft] KPA100 C83 change At 06:45 6/16/2002 -0700, Wayne Burdick wrote: >You should >definitely put in the 1000-pF unit, as it improves efficiency >considerably on the higher bands. Thanks Wayne (and the others that replied privately) I changed the C83 to 1000 pf, and it definitely reduces the current for the same power output. Makes a noticable reduction in the heat output. >Perhaps you can do this at the same time you check the tightness of the >PA transistor hardware. I was surprised how loose the PA transistors were. Those pads must really shrink after they get hot a few times. ================================================ Dave Gingrich, K9DC - Indianapolis, Indiana USA K2 #2211, K1 #931, QRP-L #2376, ARS #1109, FPQRP #389, IRLP #473, k9dc.ampr.org, CCIE #6748 ================================================ +++++++++++++++++ Date: Mon, 17 Jun 2002 15:56:16 -0500 To: "Chuck Roedel" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2/100 progress Hi Chuck: >Just finished the inventory on my K2/100 kit. >I'm missing the 1 ft. of red # 20 stranded wire and have an ORG-ORG-BLK 5% >1/4w resistor I can't find on the parts list. >I don't have stranded wire in the junk bin so I'll call "Elecraft Central" >for some on Monday. Best move here! >The manual suggests using an 800 degree tip. Why? I have one for my WTCPT >soldering station, but the 700 degree did a fine job on my K2. Is there a >specific reason to use 800 degrees? I think this was asked before, but I had >a "senior moment" and can't remember the details. The KPA100 has some rather large PC board lands to which you must solder PA transistor lands AND the bottom edges of the PC board 'ends' of T1 & T2. These require more heat than some irong can generate in a short period of time (e.g. you don't want to have to dwell on these large lands too long if you can help it). If you have a soldering gun (100W or more) with a somewhat small tip, that should work as well though will have to be careful to not 'cook' any adjacent components or wires. If you happen to have a nice, fat, 700 deg. tip for your WTCPT, then USE IT when you have to work on the larger lands. Additionally, some of the GND lands tend to sink away the heat pretty quickly... this would also be a good place to have a but more available 'reserve' heat when soldering to them. 73, Tom Hammond N0SS ++++++++++++++++++ Date: Tue, 18 Jun 2002 08:38:41 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Todd Gahagan Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Help with KAP100 and firmware version please Hi Todd, A small number of K2 microcontroller (uC) chips sent with the KPA100 kit were incorrectly labeled as 2.01F. They are actually programmed correctly as version 2.02 parts. You can verify this by installing the chip in the K2 and powering up the K2 while holding down one of the front panel keys. The K2 uC version will appear on the left side of the display. If you confirm that it is a version 2.02 part, just mark the change on its label. We caught these shortly after beginning KPA100 shipments, but a few slipped out. Sorry for the confusion! 73, Eric WA6HHQ =================== Todd Gahagan wrote: > > Building the KPA100 here and working on the control board. I thought I had > the most up to date firmware but the manual states that I should have > version 2.02A or later. I have 2.01F and did not receive a replacement IC > with the amp kit. Could someone clear this up for me please? Will the > firmware that I have work? Thanks, Todd-WA7U +++++++++++++++++++ Date: Tue, 18 Jun 2002 15:40:49 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Douglas Westover Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] New SSB Firmware Yes, it is necessary to use the latest KSB2 f/w (1.07) with the KPA100. We updated the SSB firmware to receive fast SWR and temperature power reduction commands from the KPA100. (There were no other changes.) 73, Eric ======= Douglas Westover wrote: > > New firmware for the SSB board came with my KPA100. > Just wondering what might be different and is it necessary > to replace the old chip before checking out the amp? > > 73, > Doug > W6JD ++++++++++++++++++ From: "Charles Bland" Organization: Entropy Reduction, Inc To: elecraft at mailman.qth.net Date: Sat, 22 Jun 2002 22:54:20 -0700 Reply-To: BlandRanch at BlandRanch.net Subject: [Elecraft] A tip when calibrating your KPA100 Long Story short...... If you don't get the R26/R27 calibration done properly, your power and current measurements will be way off and you will get weird results from the K2. Make sure you have a known accurate wattmeter. I had a problem and ended-up buying a Diamond SX200. I repeated the calibration procedures and my problems cleared-up. Chuck Bland #1924/100 +++++++++++++++++ Date: Wed, 26 Jun 2002 15:49:53 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 assembly note: Mistaking the FT50-43 core for the T50-10 black core. KPA100 assembly note: Mistaking the FT50-43 core for the T50-10 black core. By Gary Surrency ( support at elecraft.com ) Symptom: If the KPA100 works OK on all bands except one or two, be sure you did not use the FT50-43 dull gray core in place of one of the T50-10 black cores in the low pass filter (LPF). Two or three bands can be affected since the black T50-10 cores are used at several locations and are shared in some cases with more than one band: 30/40m; 17/20m; 10/12/15m. The red T50-2 cores are less likely to be confused, but check for their proper locations too. Result: This error will cause very low RF output on the band(s) where the FT50-43 core is mistakenly installed. Both QRP or high power modes will be affected since the LPF's on the KPA100 are in the signal path at either power level when the KPA100 is connected. Do not operate the radio in high power for more than a few seconds if this condition exists. Troubleshoot the KPA100 in QRP mode and insure no low output problems exist on any band before switching to high power. Keep the high current KPA100 supply off, or disable the PA in the Secondary Menu entry. The SWR detector will not work properly with the wrong core. Incorrect FWD and REFL power outputs from an incorrect core at T4 will make it difficult or impossible to get the FWD and REFL cal pots set properly. The C1 SWR null adjustment will also behave correctly with the wrong core. What to do: It is fairly hard to find this problem unless you recognize the symptom and notice the difference between the color of the two core types. The windings on the core makes this more difficult to see. Also do not confuse the smaller FT37-43 core with the larger FT50-43 core. The smaller core is used at T3, and the larger core is used for T4. Be certain the correct winding direction (sense) is used on the cores, so the PCB pads are lined up with the wires they connect to. The winding direction for SWR sensor T4 is critical to its operation. Follow the manual pictorial on page 27 for correct construction. Make sure the enamel is completely removed from the wires on all toroids and that they are pre tinned, bright, shiny, and clean right to the edge of the core before installation. +++++++++++++++++ From: "Leo Starrenburg PA5LS" To: "Elecraft Reflector" Date: Fri, 5 Jul 2002 15:37:25 +0200 Subject: [Elecraft] KPA100 LS Just finished the KPA, it went together with no problems. The hardest part for me was soldering the silver-mica cap. near T2, I had to make a few "dry" ie: cold runs to see if I could get the 60 W tip in the right place without damaging something else. I used the 60 W iron for all the bigger parts and for most of the leads to ground, my Weller wasn't up to that. As my inv. V is cut for 30m, I 'll have to work qro on that band only until the KAT100 is finished. The external power meter I used is a bit optimistic: the current at 100 Watts is 10.5 A on 40m, have to get an accurate power meter to do the calibration again, but I'm on the safe side for now. I had the IO-option allready installed on the K2, so I didn't bother to install the optional cap. in the Aux RF line on the K2 board. What is it's purpose and is it worthwhile to install it anyway ? 73' Leo. +++++++++++++++++++ From: "Lyle Johnson" To: "Elecraft Reflector" Subject: RE: [Elecraft] KPA100 Date: Fri, 5 Jul 2002 07:52:23 -0700 Hello Leo! > I had the IO-option allready installed on the K2, so I didn't bother to > install the optional cap. in the Aux RF line on the K2 board. > What is it's purpose... Protection in case the RF and AUX PWR cables are accidentally swapped. > ...and is it worthwhile to install it anyway ? I thought it was, opened up my K2, and made the mod. 73, Lyle KK7P ++++++++++++++++++ Date: Fri, 05 Jul 2002 12:18:41 -0500 To: "Lyle Johnson" , "Elecraft Reflector" From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: RE: [Elecraft] KPA100 THIS IS MOD THAT EVERYONE(!) SHOULD PERFORM. Even if you don't have the internal battery, you still may someday. Even if you've never swapped the cables, there's always that chance you will... I'm managed to do it TWICE now!!! And unless you have a really good vacuum-type desoldering gun/station you have a really good chance of boogering up (a mid-west US technical term, meaning... well, to booger up) your PC board. The mod is simple to do and makes it fail-safe to accidently swap the cables. Tom Hammond I, too, have mine marked... but... in BOTH instances where I swapped the cables, I had opened up the K2 in order to show the 'guts' to several onlookers in a crowd. As I was reassembling the K2 (and talking with the onlookers at the same time!) I just lost track of where I was and got them switched. At that point in time colors had no meaning as I was mostly concentrating on answering wuestions from the folks in the crowd. 73, Tom N0SS At 09:52 AM 7/5/02, Lyle Johnson wrote: >Hello Leo! > > > I had the IO-option allready installed on the K2, so I didn't bother to > > install the optional cap. in the Aux RF line on the K2 board. > > What is it's purpose... > >Protection in case the RF and AUX PWR cables are accidentally swapped. > > > ...and is it worthwhile to install it anyway ? > >I thought it was, opened up my K2, and made the mod. > >73, > >Lyle KK7P ++++++++++++++++ From: "Don Brown" To: "Jim W7RY" , "G. Thisell" Cc: "Elecraft" Subject: Re: [Elecraft] KPA100 Resistor R9 Date: Sat, 6 Jul 2002 09:42:27 -0500 Hi All very true except when the resistor is a 1% then 100 ohms is brown-bla= ck-black-black-brown. The first band is the one the next two bands are th= e two zeros and the fourth band is the multiplier of zero. The last or fi= fth band is the tolerance of 1%. A 10 ohm 1% resistor would have brown-bl= ack-black-gold-brown. In this case the gold band is a .1 multiplier. The = Elecraft manual does not list the tolerance band in the part list. This w= ill be a gold band for 5% for most resistors and a brown band for 1% resi= stors. When building one of the KPA100's I miss read the manual and installed a = 10 ohm resistor in R23 (brown-black-black instead of brown-black-black-bl= ack) but I caught my mistake when I got to the R9 install on page 34. I c= ould not find a 10 ohm but had a 100 ohm 1%. The K2 spoils you with the r= esistors all taped in order of the installation so you need to be careful= reading the color codes with the KPA100 Don Brown KD5NDB =20 ----- Original Message ----- From: Jim W7RY Sent: Friday, July 05, 2002 11:24 PM To: G. Thisell Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] KPA100 Resistor R9 Brown-Black-Black is 10 Ohms. Brown Black Brown is 100 Ohms. 73 Jim W7RY # 2740 ----- Original Message ----- From: "G. Thisell" To: Sent: Friday, July 05, 2002 5:24 PM Subject: [Elecraft] KPA100 Resistor R9 > The only resistor I have left is > Brown 1:st figure =3D 1 > Black 2:nd figure =3D 0 > Black 3:d figure =3D 0 > Black 4:th figure =3D multiplication =3D 0 > Brown Tolerance > ++++++++++++++++++++ To: vze2gmp4 at verizon.net Cc: andrew at utahdesign.com, elecraft at mailman.qth.net Date: Sat, 6 Jul 2002 21:25:54 -0400 Subject: Re: [Elecraft] KPA100 SWR adjustment problem From: Michael E Dobson On Sat, 6 Jul 2002 15:34:31 -0400 Helmut Usbeck writes: > On Saw,turday 06 July 2002 15:12, Michael E Dobson wrote: > > > Also, R26/27 should be at their mid-points for the SWR > calibration, they will be adjusted in a later step using a calibrated wattmeter. > > The ass'y manual says these pots should be all the way clock-wise. > Is the above an "official" change to the adjustment or something you tried > that makes the calibration easier. It's official, p15 KPA100 manual Rev A "Install trimmers R26 and R27 (100k, "104") near spekaer cutout. .....Set the trimmers to their midpoints." R6, the bias trimmer is set fully counter-clokwise. 73, Mike WA3KYY K2 #2221 +++++++++++++++++ From: Unifiedtx at aol.com Date: Sun, 7 Jul 2002 17:49:54 EDT To: elecraft at mailman.qth.net Subject: [Elecraft] K2/100 Updated Chip Replacements The KPA100 manual states the need to do a realignment of the CAL PLL and CAL FIL due to the K2 Control Board U6 MCU and the KSB2 U1 updated chip replacements. After replacing these chips I fould my Spectrogram patterns were not shifted enough to warrant making any changes, and the CW and CW Reverse offsets also remained correct. The CAL FIL numbers changed only slightly. I originally thought that by changing these processors I would lose all previous settings and would have to start all over again with a complete alignment. This was a nice and very pleasant surprise. I believe the CAL PLL and CAL FIL settings are stored in the Control Board U7 EEPROM. Thank you Eric and Wayne. Roy Morris W4WFB K2 #2225 ++++++++++++++++++ Date: Sun, 07 Jul 2002 15:57:23 -0700 From: Phil Wheeler Organization: Outstanding To: Unifiedtx at aol.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] K2/100 Updated Chip Replacements Unifiedtx at aol.com wrote: >The KPA100 manual states the need to do a realignment of the CAL PLL and CAL >FIL due to the K2 Control Board U6 MCU and the KSB2 U1 updated chip >replacements. > If you already had a V. 2.x MCU, likely you had already done the deed. I did and had. 73, Phil +++++++++++++++++++ From: "Francis Belliveau" To: Date: Sun, 21 Jul 2002 16:21:09 -0400 Subject: [Elecraft] Power Calibration ? On: Monday, July 15, 2002 6:10 PM "Mike Harris" wrote: > ...RFL-100... > I'm going to modify mine by including a simple ferrite core transformer to > make a -20dB pick-off (coupler) to a secondary BNC socket so that I can use > the WM-2 to measure 100W power levels e.g. KPA100 when Lisa does her stuff. > ... My question for the group is: Wouldn't it be just as accurate to read the RF Voltage across the load? This is how I calibrated the SWR circuit in my KAT2. I do not remember the exact procedure but I remember it being one of the choices in the manual. I am sure that the KPA will develop much higher voltages, but isn't the same procedure just as applicable? It would be easy to measure the voltage being developed across the RFL-100. 73, Fran +++++++++++++++++++ To: elecraft at mailman.qth.net Date: Sun, 21 Jul 2002 14:24:22 -0700 Subject: Re: [Elecraft] Power Calibration ? From: k6se at juno.com Francis Belliveau wrote regarding the KPA100: "My question for the group is: Wouldn't it be just as accurate to read the RF Voltage across the load?" ========== Keep in mind that the RF voltage across a 50-ohm resistive load will be 70.7 Vrms with 100 watts applied. If the RF probe can handle that much voltage, it should work fine. 73, de Earl, K6SE +++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] Power Calibration ? Date: Sun, 21 Jul 2002 14:48:48 -0700 My question for the group is: Wouldn't it be just as accurate to read the RF Voltage across the load? ... 73, Fran Since the power is related to the square of the voltage, any error in the r-f voltage measurement is squared as well. For example, say you have 10 vrms across 50 ohms. That equals 2 watts (10 squared = 100 divided by 50 ohms). If your measurement is off by 10%, then you might measure 9 vrms or 11 vrms, indicating a power of 1.6 to 2.4 watts - a possible error of +/- 20%. A 10% r-f voltage measurement error is very easy to have, even with a very good DMM measuring the d-c coming out of the r-f probe. The behavior of the diode in the r-f at the power level involved, the accuracy of the scaling resistances used to provide a 0.707 (rms) multiplication of the peak d-c level, or the loading effects of the DMM on a capacitor in a peak-reading meter can all add up to 10% or more measurement error very easily. Ron AC7AC K2 # 1289 ++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Jim Shaver'" , Subject: RE: [Elecraft] Setting K2 to 5W and the KPA100 Date: Sun, 21 Jul 2002 18:12:36 -0700 If I set up the K2 to be 5 Watts max, if I later add the amplifier will this power it to 100 Watts or do I have to go back and revert to the original specs? Jim Shaver ----------------- What do you mean by "5 watts max", Jim? Are you thinking of the mod that gives a slight improvement in the total current drain at 5 watts? If so, then I'd recommend forgetting it. It doesn't limit the power. It only provides a slightly lower current drain when running at 5 watts for those who want to stay at that power level and run off of the battery for as long as possible between recharging. The K2 will still run more than 5 watts with that mod if you crank up the POWER control, but it will be less efficient and it won't make the same maximum 12 to 15 watts most K2's do. Also, it cannot be used for SSB or any digital mode using the SSB module if that mod is done. The mod increases the IMD. Ron AC7AC K2 # 1289 +++++++++++++++++++ From: Gerald Pfaff Reply-To: Gerald Pfaff To: elecraft at mailman.qth.net Date: Mon, 22 Jul 2002 11:06:48 +0100 Subject: [Elecraft] K2 to 5W and the KPA100 Dear Jim, Yes, you can wire the K2 for 5 Watt and the KPA will deliver 100 Watt. That is exactly how my setup looks like. K2 #1185. The KPA puts out 100 Watts+ from 160m to 10m. 73 Gerald, HB9iRF ++++++++++++++++++ Date: Mon, 22 Jul 2002 09:32:18 -0700 From: Wayne Burdick Organization: Elecraft To: rondec at easystreet.com Cc: 'Jim Shaver' , elecraft at mailman.qth.net Subject: [Elecraft] Re: Setting K2 to 5W and the KPA100 Ron and Jim, The 5-watt winding option for the K2's PA transformer should not be used with the KPA100 if you want to run full power. More than 5 watts of drive is requried on most bands to get to 100 watts output. We'll update all relevant documentation to reflect this. 73, Wayne N6KR Ron D'Eau Claire wrote: > > If I set up the K2 to be 5 Watts max, if I later add the amplifier will > this power it to 100 Watts or do I have to go back and revert to the > original specs? ++++++++++++++++++ From: "Mike Harris" To: , Subject: Re: [Elecraft] Power Calibration ? Date: Mon, 22 Jul 2002 19:06:38 -0400 Hi folks, > Francis Belliveau wrote regarding the KPA100: > > "My question for the group is: Wouldn't it be just as accurate to read > the RF Voltage across the load?" > ========== > Keep in mind that the RF voltage across a 50-ohm resistive load will be > 70.7 Vrms with 100 watts applied. If the RF probe can handle that much > voltage, it should work fine. > > 73, de Earl, K6SE Quite so, my Fluke probe is only good for 32 volts. The idea of using a coupler is common practice. I used to run an 11 metre dish earth station (Intelsat Std. "B") and many station measurements are made using couplers, 4 and 6GHz. I still have access to the test equipment and will soon be able to measure the true coupling loss and bandwidth. The only thing I won't be able to check is if I'm getting saturation in the small transformer at the 1W level. If that becomes apparent then a bigger core is the answer. For what it's worth how it's done is to wind ten turns on an FT37-43 core, slip the core over the wire between the centre pin of the input PL259 socket and the resistor board which makes a single turn giving a turns ratio of 1:10. One end of the ten turn winding goes to the "earthy" terminal of the load and the other end goes to the centre pin of an output socket. I have used a BNC to ensure I don't mix up in and out. The only thing to remember is that there has to be a small 50 ohm load permanently on the output socket or the main load is no longer 50 ohms. Actually it should be nearer 50.5 ohms after this modification. Will post the results when I have them. Regards, Mike VP8NO (IOTA SA-002) GQRP 10148 K2 #1400 + lots of bits ++++++++++++++++++ Date: Tue, 23 Jul 2002 11:08:00 -0700 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: elecraft at mailman.qth.net Subject: [Elecraft] VFO ALC/10M Mod kit We are currently shipping the VFO ALC/10M mod parts kit with all KPA100s. (This helps improve spectral purity on a small number of K2s that need it when running 100W). A few of you who received the first lot of KPA100s did not receive this kit and will be receiving it shortly from us. (Sorry we missed you in the initial shipping rush!) Please do -not- contact Gary ( support at elecraft.com ) unless it does not arrive over the next couple of weeks. This mod is not essential for basic K2s running without the KPA100. For those of you who feel you will not be purchasing a KPA100 and really want to do it now (some of us are mod addicts..) we will make it available for our cost 0f $15 plus shipping. Order the VFO ALC/10M mod kit, part number E850093, by adding this information in the comments section at the bottom of our secure order form at http://www.elecraft.com . 73, Eric WA6HHQ +++++++++++++++++ From: "Don Brown" To: , "Elecraft" Subject: Re: [Elecraft] KPA100 CAL tPA Date: Thu, 25 Jul 2002 19:45:07 -0500 Hi The heatsink calibration is done from the menu not the bias control R6. I= f the calibration is not set right the fan may not turn off. You need to = measure the heatsink temperature and set the menu setting to the same val= ue. I use a Fluke temperature meter with a thermocouple held against the = heatsink to measure the temperature. If you don't have this setup then yo= u could lay a thermometer on the heatsink and read it that way or put the= radio in a room where the temperature is known for one or two hours turn= ed off to allow the heatsink to adjust to the room then turn on the radio= and set the menu value quickly before the heatsink changes due to heat f= rom the radio. Don Brown KD5NDB 4 K2's 3 K1's all options 2 KPA100's =20 ----- Original Message ----- From: Unifiedtx at aol.com Sent: Thursday, July 25, 2002 6:48 PM To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 CAL tPA Can anyone tell me if it is possible to recalibrate the temperature setti= ng so the fan doesn't run unnecessarily without turning the bias control, R6= , back to counter-clockwise. This may be a futile cause since the fan will switch to HI at a heatsink temperature of 40C and will turn off within 2 = to 4 minutes after going below 37C. Mine doesn't seem to cut off at 37C (100F= ) because it runs a long time after the heatsink fins feel cool (near room temperature, 25C or 78F). Roy Morris W4WFB ++++++++++++++++++ Date: Mon, 29 Jul 2002 17:11:08 -0700 From: Wayne Burdick Organization: Elecraft To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 stripped screw threads -- solution We have a solution for this already in the works. The hole in the K2's side panel, as well as the grooved channel in the KPA100 heat sink, will accept a #5-40 TapTite screw. The #5 body is slightly larger than #4, has a slight taper at the tip, and provides a much better "bite" into the heat sink. (By the way, the side panel screws are not required electrically or thermally, so if they're stripped, it will not affect operation of the K2 at high power.) We have these new screws on order and will make them available as soon as possible--probably about 3 weeks. **** PLEASE NOTE! **** We ask that you DO NOT call or e-mail Elecraft support about this yet. This will just slow Scott and Gary down on other tasks. When we've gotten the new screws in, we'll provide a way to obtain them directly from our web site. Watch for this announcement. 73, Wayne N6KR +++++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] Soldering iron tip temperature for KPA100 Date: Sun, 4 Aug 2002 18:49:34 -0700 The point has probably already been made, but there is a big difference between HEAT and TEMPERATURE. Many times people will use a too-high TEMPERATURE to make up for inadequate HEAT (related to the wattage of the iron). They use the thermal mass of the soldering tip to store extra thermal energy, and allow the heat to flow from the resulting heat reservoir (which quickly lowers the tip temperature, hopefully to a safe value) The idea of a temp-controlled iron is that it limits the tip temperature, but provides heat to the joint as required up to the limit of the iron. You could argue that for large joints that require a lot of heat, you can use a small, low-wattage iron at 1,000 degrees F - but I wouldn't recommend it. One must be careful when soldering that the temperature does not exceed the ability of the PC board or the component to absorb the thermal shock that occurs when the iron is brought to the junction of the part(s) and board to make a connection. An extreme case is charring of the board. A more common case is "lifting the pad" which occurs when the copper+tin plating on the board expands and overcomes the adhesive bond which holds it to the board. This results because the pad was allowed to reach too high of a temperature. Another danger is cracking the plating between the plated-through hole in the board and the pad on the surface of the board. This can occur even when the pad doesn't appear to have "lifted" and cause an unreliable connection which won't fail until Field Day. I have used systems where a part was soldered and desoldered from a board hundreds of times with no damage to the board/pad adhesive or the part. And I have used systems where one or two applications of the iron and the pad was ruined. In both cases, the difference was in controlling the temperature of the iron, the board and the components. As a result of these experiences, I never use an iron temperature of more than 700 degrees. If I need more heat, I use two irons, or a larger iron, but never a higher temperature. Solder melts at the same temperature regardless of your iron. If you are using more than 700 degrees, you have a heat problem, not a temperature problem. In the case of the KPA100, I used two small irons (Hakko 936 + Edsyn 951SX) in the steps soldering Q1 and Q2 emitter tabs to the ground plane because I don't have a higher heat capacity iron and didn't want to buy one. IMHO, YMMV. 72, Lyle KK7P +++++++++++++++++ From: W5EI at cs.com Date: Sat, 10 Aug 2002 15:00:59 EDT To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 question answered Somehow I contrived a way to install the coax connector on the wrong side of the rear panel. Thanks to Pauli and Don for the suggestions. Thanks and 73, Don, W5EI KPA #2478 +++++++++++++++++ From: "Don Brown" To: , "Elecraft" Subject: Re: [Elecraft] Initial test - resistance check in KPA100 contradicting measureme Date: Mon, 12 Aug 2002 16:06:35 -0500 Hi In circuit resistance measurements will vary somewhat with different bran= d of meters. The semiconductors in the circuit will modify the resistance= measurements and will depend on the driving current the meter using and = the range selected. You should look for readings way off before any conce= rn. I would not worry about it. The voltage measurements are more critica= l and should agree with the manual within a few percent. Don Brown KD5NDB =20 ----- Original Message ----- From: Rolf.Schroeder at t-online.de Sent: Monday, August 12, 2002 3:49 PM To: elecraft at mailman.qth.net Subject: [Elecraft] Initial test - resistance check in KPA100 contradicti= ng measurement results Hi, while measuring the resistances according to page 20 of the KPA 100 manua= l, I =20 found the following: while measuring in th 20k range, all resistances that should have been >1= 0k =20 were around 8.3k: U1 pin 2, 3, 13, 14, 27, 28, or U4 pins 1 and 8(too low= ) When measuring in the 200k range all resistances were in the 35k range, =20 measuring in the 2M range produced measurements of about 250k or, to be m= ore =20 specific: DVM range: 20k 2M 20M U1 pin1 3,7k 3,9k 3,8k U1 pin2 8k 34k 255k U1 pin3 8,3k 34,7k 260k More values upon request but pattern is the same for the rest of the pins= of =20 the ICs. Measuring between banded end of D10 and ground as well as measur= ing =20 between AF pad and gound showed infinite resistance. I am using a Metex =20 M4640A DVM and have replaced the battery of the DVM just ten minutes ago.= =20 (thought it might have been a weak battery. Any ideas? -- =20 Best Regards Mit freundlichen Gr=FC=DFen Rolf Schr=F6der They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety. =20 - Benjamin Franklin, 1759 - =20 ++++++++++++++++ From: Unifiedtx at aol.com Date: Fri, 16 Aug 2002 14:42:36 EDT To: elecraft at mailman.qth.net Subject: [Elecraft] Securing Q3 and Q4 on KPA100 Gary Surrency has suggested that Q3 and Q4 be secured to the heat sink with a thick fiber washer (like the speaker washer) rather than the split washer that can bite into the plastic transistor body and damage it. Fiber washers about the size of the speaker washers can be found at Home Depot. The washers to use are the #4 x .032". The hole in these washers are slightly larger than the screw diameter which should let the washer seat properly if the transistor is not in perfect alignment with the PCB hole. I am not using the split washer on top of the fiber washer, and I don't believe Gary uses the split washer on top of the fiber washer either. If these screws are tightened with normal torque, they will stay put. Roy Morris W4WFB K2/100 #2225 +++++++++++++++++++ From: "Don Brown" To: , "Elecraft" Subject: Re: [Elecraft] Securing Q3 and Q4 on KPA100 Date: Fri, 16 Aug 2002 15:20:00 -0500 Hi The correct part to mount this type of transistor is a dish rim lock wash= er but they are hard to find. I used a flat washer and a split lock so th= e lock washer is biting into the flat washer not the transistor case. The= fiber washer sounds like a good solution also. I have heard of several c= racked transistor cases because of the lock washer biting into the case o= f the transistor. Don Brown KD5NDB ++++++++++++++++++ From: "Douglas Westover" To: "Doug Person" , Subject: Re: [Elecraft] Setting bias current on KPA-100 Date: Sun, 18 Aug 2002 16:08:41 -0700 Hi Doug, I found the bias setting to be fairly critical. I had a problem with the KPA becoming very unstable on SSB and spent a lot of time bugging Gary. Finally turned out to be the bias adjustment which I had originally set with an old analog VOM with very poor current resolution. 73, Doug W6JD ----- Original Message ----- From: "Doug Person" To: Sent: Sunday, August 18, 2002 10:05 AM Subject: [Elecraft] Setting bias current on KPA-100 > How important is it to set the bias current accurately. None of my meters > seem to do very well in the necessary range. They all tend to go 0 to 200ma > and then jump to 10 amps. At the higher setting resolution isn't very good. > I think I'm OK and near enough but wonder whether to err over or under. > > I also notice that KPA is very sensitive to SWR. It starts to back down > power at 1.5:1 or more. Are the finals really that sensitive? I notice too > that the fan doesn't seen to run much. Is it better to set it so it runs in > slow all the time? Or is it fine to just leave it in the normal position? > > Doug -- W4DXV > K2/100 #1920 K1/4 #1297 +++++++++++++++++ From: "Don Brown" To: "Douglas Westover" , "Doug Person" , "Elecraft" Subject: Re: [Elecraft] Setting bias current on KPA-100 Date: Sun, 18 Aug 2002 18:58:44 -0500 Hi If your meter does not have a current range or the current range does not= give the resolution you need you can measure the current with a 0.1 ohm = 1% 5 or 10 watt resistor. Just connect the resistor in series with the po= wer supply and read the voltage drop across the resistor. 0.100 volts wil= l be equal to 1 amp of current. So when adjusting the bias current the re= ading is going to be around 0.800 to 0.950 volts for 800 to 950 ma. It is= best if you can get a 1% or better resistor but if you have several in y= our junk box get one a little high in resistance and parallel a higher sm= all resistor until it is as close to .1 ohms as possible. A lot of meters= have a relative function that will allow you to subtract out the lead re= sistance so you can get a accurate reading on the resistor. Use short hea= vy leads with alligator clips. Short the clips together on the lowest ran= ge and press the relative button then put the resistor in the clips to me= asure. =20 I like using a current shunt like the .1 ohm resistor instead of using my= meter current ranges. It is to easy to forget and leave the meter on the= current function and then try to measure how much current your power sup= ply can output. Usually blowing the fuse in the meter or worse damaging t= he internal current shunt. You can make up several of these external shun= ts in small boxes with 5 way binding posts in 1 ohm .1 ohm and .01 ohm va= lues Don Brown KD5NDB ++++++++++++++++++ Date: Sun, 18 Aug 2002 20:16:21 -0500 To: elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] KPA-100 Bias Adjustment WITHOUT AN AMMETER Weveral folks recently have commented that they had problems adjusting the BIAS on their KPA100 because they didn't trust the current measurement capabilities of their test equipment. Here's a message which was posted to the KPA-100 FIeld Tester's reflector while we were busy FTing the pre-release KPA-100. Maybe this will help some of you. WAYNE: If this is no longer a valid method, PLEASE advise a.s.a.p. - Tom N0SS _____________________ Sam, N5WU wrote to the KPA-100 Field Test group a while back: I do not have the luxury of a current meter on my power supply and I couldn't get my ammeter working to measure the current into the K2/100 so Wayne sent me a suggestion that worked well for me. For those of you in the same fix, here is a work around that works very well. Make sure the power to your K2 is off. Using small clip-on leads, clip these to either side of R7. That is the large black resistor in the center of the board toward the back of the amp. With the leads connected, set you voltmeter for the lowest reading you have, at least 1/10 of a mv. Set R6 fully CCW. Turn on the K2 and look at the meter. Write down the mV reading. It will be very close to 0.0mV or just a little more. Mine was at about 0.5mV. Go to CW TEST Mode (VERY IMPORTANT TO BE IN "TEST" MODE) and press Tune. Now adjust R6 for a meter reading of 2mV greater than the receive voltage you just wrote down. Tap any key to get out of tune. That is all there is to it. My R6 ended up at about the 4 to 5 o'clock position when viewed from the front of the unit. Happy adjusting..... Sam N5WU +++++++++++++++++++ From: "Don Brown" To: , "Elecraft" Subject: Re: [Elecraft] KPA100: Wire size for Z1 - is #22 enough? Date: Mon, 19 Aug 2002 07:57:20 -0500 I save the clipped leads from the 1N4007 diodes to use for all of the jum= pers on the boards (grounds, options, ect.) they are about .030 or 22 GA = and work well. I would not use enameled wire because of the problems of s= tripping and getting a good solder joint. If you want an even heaver wire= for Z1 then save the wire clipped from the .005 ohm current sensing resi= stor. =20 Don Brown KD5NDB ----- Original Message ----- From: Rolf.Schroeder at t-online.de Sent: Monday, August 19, 2002 6:42 AM To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100: Wire size for Z1 - is #22 enough? Hello to the fellow builders, after all these toroids... Would a piece of #22 enameled wire be good enough as a basis - there are =20 warnings not to use small component leads. #22 wire might be a bit small for =20 20A? -- =20 Best Regards Mit freundlichen Gr=FC=DFen Rolf Schr=F6der Mail: rolf.schroeder at t-online.de ++++++++++++++++++ Date: Mon, 19 Aug 2002 13:05:29 -0500 To: Rolf.Schroeder at t-online.de (Rolf G. Schroeder), elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] KPA100: Wire size for Z1 - is #22 enough? Rolf: >Hello to the fellow builders, after all these toroids... >Would a piece of #22 enameled wire be good enough as a basis - there >are warnings not to use small component leads. #22 wire might be a bit >small for 20A? I would recommend a larger wire here... something closer to #20 (0.32" / 0.813 mm) or #18 (0.040" / 1.02 mm). As is stated in the KPA100 manual, a clipped lead from one of the 1N4007's or one of the 3W resistors works well. These leads are #20. 73, Tom Hammond N0SS +++++++++++++++ From: "Mike Harris" To: Date: Mon, 19 Aug 2002 19:46:41 -0400 Subject: [Elecraft] KPA100 Bias and R26 Hi, Finally got the beast buttoned up. Comments to add to those made by others: Power Calibration (R26 and R27) - Page 45 I adjusted this as instructed at the 5W level. I think this should only be taken as a good starting point for further adjustment. After completing the construction full power tests indicated about 85W output max. Re adjusted at 50W and now the output tracks OK all the way to 100W. Output was measured into an OHR 100W load with a Bird 43 fitted with a 100W, 2-30MHz slug. An immediate follow up measurement was made using a OHR WM-2 connected to the coupler port (-20dB) I added to the 100W load. I was pleased to see that 100W indicated on the Bird 43 translated to 1W on the WM-2 (100W at -20dB). I can now have confidence that the coupling transformer on the small FT37-43 core isn't saturating at 100W/1W. Bias current adjustment - Page 47 Readings on my KPA100 Point #5 - 290mA Point #6 - 475mA + 400mA for Q1+Q2 = 875mA Quick adjust to 875mA +/- Current slowly climbed to 975mA +/- I would strongly recommend that when mating the KPA100 to the K2, remove the right hand side panel so that the cables can be tucked in neatly, especially the ribbon cable. For what it's worth. Regards, Mike VP8NO (IOTA SA-002) GQRP 10148 K2/100 #1400 +++++++++++++++++ Date: Mon, 19 Aug 2002 17:25:23 -0700 From: Phil Wheeler Organization: Outstanding To: Mike Harris Cc: Elecraft at mailman.qth.net Subject: Re: [Elecraft] KPA100 Bias and R26 Mike Harris wrote: > >I would strongly recommend that when mating the KPA100 to the K2, remove the >right hand side panel so that the cables can be tucked in neatly, especially >the ribbon cable. > Good idea, Mike -- especailly the first time. I ended up with the power cord pinched between the right side of the case and the shield. After a few seconds of operating, the output went to zero. Fortunately my power supply has a crowbar and shut down before the fuse even blew. Now that I have the cables "trained", I no longer remove the side panel when doing an R&R. 73, Phil ++++++++++++++ Date: Sat, 07 Sep 2002 12:45:31 -0500 To: "John Weber" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] KPA100 Fan Test John: >On page 46 at the fan test section, I found that it would not work=20 >properly until I set the power out at greater than 10 watts. Drove me=20 >crazy for a while since there is no mention in the manual of that. Normal? If I recall, this is normal. >Related question. Page 47 sixth step seems to indicate that fan should=20 >run if power is set to 11 watts. My fan does not come on at any setting of= =20 >the power control. It does however come on after transmitting for a while= =20 >at QRO levels. Is this normal? The FAN parameter (p. 50 of the KPA100 Rev A manual) allows you to select=20 the action of your fan as below: Whenever you're editing the PA menu parameter, you can also tap [DISPLAY] to change the KPA100 fan mode: =B7 FAN nor - the normal setting (goes to low or high if needed) =B7 FAN LoH - keeps the fan at low speed, going to high if needed =B7 FAN Hi - keeps the fan at high-speed at all times in QRO mode >If so, what is the best way to set the bias? Add 450 ma instead of 400 ma? NO! Adjust BIAS when the fan is NOT running. In fact, set the K2 to TEST=20 mode in CW, so you cannot actually transmit. This should still allow you to= =20 'key' the KPA100, but without any RF being present, so you won't raise the= =20 temp of the heatsink, and the fan won't turn on. If you have FAN set to either FAN LoH or FAN Hi, set it to FAN nor before=20 setting the bias. Hope this helps. 73, Tom Hammond N0SS ++++++++++++++++++ From: "Don Brown" To: "JAKidz" , "Elecraft" Cc: "=?iso-8859-1?Q?Tom_HammondN=D8SS?=" Subject: Re: [Elecraft] Setting KPA100 Bias? Date: Fri, 18 Oct 2002 07:43:49 -0500 Hi I use the analog bar graph on my Fluke 87 DMM to set the bias to the corr= ect value immediately after hitting tune. The reading will climb over the= next second or 2 but I ignore anything after the initial reading. That i= s why I like the bar graph on the Fluke DMM as it has a 40 times a second= reading rate while the digital display has a 4 times a second reading ra= te. Analog is better for making this type of peak reading that is why Fl= uke includes the bar graph on most of their meters. If your DMM does not = have this feature then try to use the first or second reading after you h= it tune. Go out of tune and try again several times until you get a good = reading as soon after hitting tune as you can. Don Brown KD5NDB ----- Original Message ----- From: JAKidz Sent: Friday, October 18, 2002 12:41 AM To: elecraft at mailman.qth.net Cc: n0ss at earthlink.net Subject: [Elecraft] Setting KPA100 Bias? Greetings, Tom and the Group: How fast is "when you first enter TUNE mode"? Given 532 mA, my target is 932 mA. When I hit TUNE in CW TEST, it looks like the current is followin= g an exponential curve, the rate of increase slowing to a slow change after about 25 seconds. If I set R6 for the target current in a few seconds, th= e plateau is about 1.2A or higher and I wouldn't say it is slowly drifting higher from the 932 mA. Is the resistance in my jury-rigged meter cabling between the power supply and the K2 cable causing an unusually long time-constant? Is N5WU's method, posted by Tom, of measuring the voltage change across R= 7 likely a better method in my case? Or am I about to enter the Trouble Shooting mode in the upcoming Transmit Tests? Thanks much. John, K7JG. +++++++++++++++ Date: Fri, 18 Oct 2002 09:50:24 -0500 To: "JAKidz" , From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: [Elecraft] Re: Setting KPA100 Bias? GM John: >How fast is "when you first enter TUNE mode"? Given 532 mA, my target is >932 mA. When I hit TUNE in CW TEST, it looks like the current is following >an exponential curve, the rate of increase slowing to a slow change after >about 25 seconds. If I set R6 for the target current in a few seconds, the >plateau is about 1.2A or higher and I wouldn't say it is slowly drifting >higher from the 932 mA. Is the resistance in my jury-rigged meter cabling >between the power supply and the K2 cable causing an unusually long >time-constant? If I recall, and I don't think it's menthioned in the manual, Wayne kinda intended for the bias to be set when the heatsink was cool, and without the fan running (due to heatsink temp, NOT because it's been turned off). The bias WILL change as a function of heatsink temperature. This is possibly why you will see the slow increase over time. I believe a slow run-up of the bias current is probably a fact of life, but sould not be a significant hinderance in setting the bias. I wouldn't expect it should take more than 5 seconds to actually MAKE the bias setting, maybe less. This shouldn't contribute terribly to heatsink heating. If you DO need to repeat the step, wait a bit, to give any 'localized' heatsink heating a chance to dissipate before you hit it again. And use an analog meter if one is available. The bias CAN be set +/- a few mA... maybe +/- 20mA, but I'd want to get a reading from either Wayne, Eric, or Gary on this before I'd ask you to take it as gospel. >Is N5WU's method, posted by Tom, of measuring the voltage change across R7 >likely a better method in my case? There's probably not significant difference in the two methods... esp. with regard to you seeing the bias slowly increase. >Or am I about to enter the Trouble Shooting mode in the upcoming Transmit >Tests? I doubt it... sounds like you'll be OK. 73, Tom ++++++++++++++