++++++++++++++++++++ See also KPA100_Debugging ++++++++++++++++++++ Date: Thu, 26 Dec 2002 13:29:12 -0500 Subject: Re: [Elecraft] KPA100 Help PLEASE Cc: elecraft at mailman.qth.net To: Ned Asam From: Pete Meier Thanks to Lyle and Ned I have found my problem. It was a lifted land between RP1 P5 and U1 Pin 7 on the underside of the PA board. No other component problems were discovered. Voltages and resistances are all nominal so I'm not sure what caused the break in the land. It was right at a open feed through hole. All appears normal now. So on the next section of test and alignment. Thank again guys for the quick help. Pete WK8S On Thursday, December 26, 2002, at 12:31 PM, Ned Asam wrote: > Peter, > > Good, you are making progress. > > My next suggestion is the same as Lyle's. Check the voltages around > Q12. This is an FET switch which is off when the 12 PA is missing. If > this FET switch is off, the voltage at pin 7 of U1 will be 0 -- if on, > expect a positive 6 + volts at pin 7. Check the voltage levels all > around Q12. > > Good Luck... > > ...Ned, KC2FLM > > [Elecraft] KPA100 Help PLEASE > > Lyle Johnson wa7gxd at fidalgo.net > Thu Dec 26 11:37:01 2002 > > Previous message: [Elecraft] KPA100 Help PLEASE > Next message: [Elecraft] K2 resistance checks > Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] > > > > > I have completed the KPA100 upgrade but cannot get the K2 to > recognize > > it. With a 20 amp supply connected I still get NO PA PS. > > > Check and verify that you have between about 3V and not more than 6V > at U1 > pin 7. This senses the presence of the "12PA" source and is most > likely > what the KPA100 CPU uses to verify there is a power supply attached and > working. See Sheet 2 of the schematic, in the upper left. R8, Q12, > RP1. > You should see about +12 on the 12PA side of R8, About +4 on the > source and > drain of Q12, and about +12 on the gate of Q12. > > 73, > > Lyle KK7P > > > > > At 11:11 AM 12/26/2002 -0500, you wrote: >> Hi Ned, >> >> I am only using the high current connection. I have no problem with >> low power xmit/receive on any band. I am getting about 120 volts at >> R11, R12. >> >> Pete >> >> >> On Thursday, December 26, 2002, at 10:34 AM, Ned Asam wrote: >> >>> Peter, >>> >>> It sounds like you almost working, since all the low power circuits >>> seem to be working. I assume the LP filter relays on the KPA 100 >>> are also working. That is, you can transmit and receive at low power >>> on all bands. All these circuits are powered from the low power >>> source on the base K2. >>> >>> What happens when you disconnect the low power 12 volts, and the >>> high power 12 v is still connected? If all is off, then this would >>> also point to the High Power 12 volt path. >>> >>> If I understand the situation correctly, I would trace the high >>> power 12 volts from the back of the unit through the amplifier >>> section -- r13, c75, rfc1 and so on... >>> >>> Are you getting the 90 to 150 volts at R11 and R12? This is >>> generated on the KPA from the high power 12 volt source. If not, >>> check all around T3 for good solder connections.etc... >>> >>> Regards, >>> >>> Ned, KC2FLM +++++++++++++++++ From: "Brian Machesney" To: "'elecraft'" Date: Fri, 27 Dec 2002 16:38:45 -0500 Subject: [Elecraft] RE: KPA100 bringup problem: only 1-W of output Thanks to all those who wrote with suggestions. The "blind troubleshooter" award goes to those who suggested I look at the KPA100 input section. Indeed, one of T4's inputs wasn't soldered properly; in fact, it was difficult to get a good joint here, for some reason. It's alive; first QSO with K4PV lasted over an hour -- Jim wanted to know everything there was to know about the K2. Think we have another convert! 73 Brian K1LI +++++++++++++++++ Reply-To: "Nick Frost" From: "Nick Frost" To: Date: Fri, 3 Jan 2003 23:35:52 -0700 Subject: [Elecraft] KPA100 power output fixed Recently I wrote asking for help with a KPA100 that put out either 5 watts or 100 watts and would not vary the output. From 0-10 watts LCD setting, the KPA100 was outputting 5 watts on the meter and jumped to 100 watts at the 11 watts setting. I fixed the problem by re-winding T4 which I had initially wound correctly but may have connected incorrectly, *AND* by following Gary Surrency and Tom Hammond's excellent suggestions which are: turn off the PA and remove the high-current power supply. Use the low-current power supply into the K2 and do the power calibration with 5-15 watts and when finished, then turn on the PA with high-current and see if the power on your wattmeter reflects the applied setting on the LCD/power knob as you vary the power setting. This worked for me, now the KPA100 varies the output power from 5 to 100 watts. So, many thanks to Gary and N0SS for their help, and for all of you on this list and for your posts. I wanted to document it here for others who might be searching to resolve this problem. Thank you! -Nick KD5QEF ++++++++++++++++++ From: Bradbeerfamily at aol.com Date: Fri, 10 Jan 2003 14:06:30 EST To: elecraft at mailman.qth.net Subject: [Elecraft] KPA100 temp problem For Leo, PA5LS. Have you set up your ambient room temperature as per the instructions? I only finished my KPA100 a couple of weeks ago, and on switching on, my fan was running all of the time too. It was only when I got to the temp calibration phase (CAL TPA, I think) and adjusted the setting to match the room temperature that the fan came under control. regards Paul M0CVX ++++++++++++++++++ Date: Sat, 11 Jan 2003 09:25:46 +0100 From: dl1iaq at t-online.de (Martin) To: elecraft Subject: [Elecraft] Wider range for the 10m Bandpass-Filter Hi gang. After performing the 10mBPF-mod for use with the KPA-100, I was not satisfied with the performance of my K2. The range of the BPF was too narrow for my needs and sensitivity quickly dropped when tuning higher in band. I mailed to the reflector, but never got an answer from you ´crafters. So I mailed directly to Wayne, N6KR, who suggested to try different coupling-condensers (C45). I played around a bit, the results can be seen on Sverre´s -LA3ZA- website http://www.qsl.net/la3za/K2/10mDL1iAQ.pdf It might take another day or so until Sverre puts it in his Modification-list. Thanks to Sverre for providing the webspace. 73 Martin DL1iAQ +++++++++++++++++++ From: "Don Brown" To: "Richard Stasiak" , Subject: Re: [Elecraft] KPA100 - RS232 difficulties Date: Sun, 12 Jan 2003 13:52:22 -0600 Hi Did you do the mod to the control board and if you did check it to be sure you got it right. It is easy to put the jumpers on the wrong pins. Don Brown KD5NDB ----- Original Message ----- From: "Richard Stasiak" To: Sent: Sunday, January 12, 2003 1:38 PM Subject: [Elecraft] KPA100 - RS232 difficulties > Hello fellow Elecrafters > > Just finished up the KPA 100 - the PA works fb. > > However, I cannot get the RS232 port to work. > > I have checked the computer cable three times and resoldered the pins of U4. > > I can turn the port on and off, using the menu command > > Using Hyperterminal, I can get the K2 to send the frequency to the computer > ok., but I cannot send the command (SW01;) to the K2 to get it change > bands. > > When I run K2 remote and select the COM port, K2 Remote comes back with an > error message to check the RS 232 connection or make sure the K2 is powered > up. > > Anyone have any suggestions or ideas on things to check? > > 73 > > Rick VE3MM > K2/100 #1591 +++++++++++++++++ From: "Rich Lentz" To: "'Richard Stasiak'" , Subject: RE: [Elecraft] KPA100 - RS232 difficulties Date: Sun, 12 Jan 2003 14:30:33 -0600 Make sure the interface cable is wire exactly as shown in the diagram. Haven't built the KPA100, but know the diagram is in the KIO2 manual, = which can be downloaded. I got the exact same problem when I tried a three = wire cable that I had use on other rigs. The K2 remote looks to see if pins = 7 & 8 are hooked together, if not, then it gives you the error message. May want to check the PC end of the cable with an ohm-meter to be sure. Rich KE0X=20 +++++++++++++++ From: "Richard Stasiak" To: , "Don Brown" Date: Sun, 12 Jan 2003 19:20:32 -0500 Subject: [Elecraft] KPA100 - RS232 difficulties ----- Original Message ----- From: "Richard Stasiak" To: "Don Brown" ; Sent: Sunday, January 12, 2003 3:28 PM Subject: [Elecraft] KPA100 - RS232 difficulties > Don > > Thanks for the quick reply. You hit a home run!!!! or more appropriately > for us Canadians scored a goal on the penalty shot!!!!! > > I had made the mods on the control board. But it was far easier to check > them, than taking the KPA100 apart. > > The jumpers were in the correct spots but I had a cold joint at the jumper > connection to P4 pin 1. > I redid it and plugged the board back in. It never occurred to me to check > those mods until your suggestion. > > Right away K2 Remote worked fine. > > 73 > > Rick VE3MM > > ----- Original Message ----- > From: "Don Brown" > To: "Richard Stasiak" ; > Sent: Sunday, January 12, 2003 2:52 PM > Subject: Re: [Elecraft] KPA100 - RS232 difficulties > > > > Hi > > > > Did you do the mod to the control board and if you did check it to be sure > > you got it right. It is easy to put the jumpers on the wrong pins. > > > > Don Brown > > KD5NDB > > +++++++++++++++++ From: "Lyle Johnson" To: Subject: RE: [Elecraft] PA Menu Paramter Date: Mon, 13 Jan 2003 18:03:08 -0800 > While my K2/100 + KAT100 all seem to be individually working > correctly and playing well with each other, I by chance > discovered that the PA menu Error parameter occasionally reads > quote E8 unquote. Can someone please tell me what that means? > This is on the KPA100 errata sheet, also found on the Elecraft web site in the manuals section. "8. This code will always be seen after setting CAL TPA, but it can also indicate a problem with the KPA100 MCU or its on-chip EEPROM. If it's just the CAL TPA indication, it can be cleared by turning power off and back on." 73, Lyle KK7P +++++++++++++++++ From: "Leo Starrenburg PA5LS" To: "Elecraft Reflector" Date: Mon, 20 Jan 2003 22:14:01 +0100 Subject: [Elecraft] KPA troubles: the outcome. LS the replacement U6 arrived today, along with a spare MCU. After placing the ic on the KPA pcb I followed the alignment procedure and everything turned out fine. Even the ventilator is behaving again, so there is no need to replace the MCU. ( If I hadn't orderd it, I probably would have had to replace it ...) So now I am the proud owner of a K2 with KAT2 and internal battery, and a KPA- and KAT100 in an EC2. Happy days indeed ! I did do the "KAT100" modification on the K2 control board ( extra resistor in the control line ), but I do not have the xx Ohm 3W resistor in the RF feedline, works ok with the one foot RG58-U coax between the K2 and KPA100. A last remark: as U6 provides powerlevel feedback to the K2, the lack of it in my set-up resulted in a 200W+ output, and before I realised what was going on I went on and did this several times. So I can safely say that the KPA100 is a very fool-proof and indeed conservativly rated design (!) 73' Leo PA5LS. ++++++++++++++++++++ From: "Don Brown" To: , Subject: Re: [Elecraft] KPA100 Problem solved Date: Mon, 20 Jan 2003 16:32:45 -0600 Hi Don, Leo and all Maybe a little circuit description of the Temperature measuring circuit will help locate the problem. This circuit is similar to a temperature probe I worked on at Tektronix. If a constant current is forced through a transistor the base-emitter junction voltage will track fairly close to 10 mV change per 1 degree C. A large value (15K) resistor causes a constant current to flow in Q3 and U7B, Q4 buffers the base voltage of Q3 and forms a temperature regulated drive for the PA transistors. The base voltage at Q3 is also sent to an analog input on the KPA100 MPU. The firmware uses this voltage, that varies with temperature, to calculate the heat sink temperature. This works because Q3 is screwed to the heat sink so its base-emitter junction will be at the heat sink temperature. If Q3 was not screwed to the heat sink it would measure the ambient temperature in the K2. It should not read a very high temperature. I think the tightening of the screw may have flexed the board or the transistor, causing a bad connection somewhere to reconnect. The problem may come back. There is not enough current flowing in Q3 for it to self heat. What is worse if there is a problem in the temp measuring circuit it could over drive the bias on the PA transistors and cause the transistors to overheat. I had a KPA100 today I was working on with the bias misadjusted. If you keyed the mic the KPA100 would draw 10 amps without speaking into the mic. The normal draw should be a little less than 1 amp. After adjusting the bias everything was fine. I mention this because this is the symptom you would have if Q3 was not working or a bad connection in the temperature measuring circuit. If a split lock washer is used on Q3 and Q4 without a flat washer or fiber washer the split lock will sometimes crack the case of the transistor if tightened to much. I use a fiber washer like the ones used to mount the speaker on Q3 and Q4's mounting screws to cushion the transistors. Don Brown KD5NDB ----- Original Message ----- From: To: Sent: Monday, January 20, 2003 3:29 PM Subject: [Elecraft] KPA100 Problem solved > Leo, > > I don't believe anything was actually getting hot, because the PA hot message > appeared upon intial power-up when the heat sink was quite cold to the > touch. The high temp reading in the CAL tpa menu setting would also show an > extremely high temp reading even when the ambient temp. in my shack was only > 5 deg. C early in the morning. It's almost as if the erratic readings might > have been caused by a crack in the case of Q3, a possibility suggested by > Don, KD5NDB. I could not find such a problem when I looked at Q3; it was > quite loose however. > > 73, > > Don ++++++++++++++++++ Date: Sat, 08 Mar 2003 18:29:28 -0500 From: "Carter W. Craigie" To: Elecraft List Members Subject: [Elecraft] KAT100 to DX4WIN Problem SOLVED! JOY! Hi again! I received two responses to my query: From Phil WD8QWR and from Rich KE0X, and my thanks to you both. Rich nailed my problem: I had the cable plugged in backwards! The end that should have gone into the rig was plugged into the KAT100 and vice versa. As soon as I changed the plugs -- SHAZAAM!! Everything worked PERFECTLY! I am so appreciative! 73, Carter Carter Craigie N3AO K2/100 S/N 678 K1 S/N 159 ++++++++++++++++++++ To: rvickers at hobbsbondedfibers.com, elecraft at mailman.qth.net Date: Fri, 28 Mar 2003 08:15:50 -0500 Subject: Re: [Elecraft] KPA100 Low power on the low bands From: Daniel L Brinneman Hi, Take out your KPA100. Turn the basic K2 on. If you have the KAT2, put it in the CAL P mode on ATU menu. If not hook up your basic K2 RF-board antenna to an external wattmeter which is hooked up to a good 50 ohm dummy load. Use an oscilliscope on AC coupling. Set your radio to a band of choice, such as 80m. With the oscilliscope probe, put ground lead on a ground point, make sure that your alligator clip has NO WAY of shorting out a component on either side of the ground point if you were to move your hand. If it does, you will definitely short a component out. With the front of the K2 facing you, identify the LPF section in the back right-hand corner near the RF-board antenna. If you have the 160m option in, you can take the screw out, take out the module from the pins and lay the board; still attached to the RX antenna; outside the K2 upside down to the back left. To be safe follow this procedure. Use your RF board schematic (sheet 3 of 4) for these correct test points. On oscilliscopes' probes there is a hook which can be removed to produce a point. Connect your osciliscope's probe ground to a ground point on the K2. Make sure that it will NOT short anything else out while the radio is on. The 80m LPF is at the very back of the radio under or behind the 160m module. Notice the very left torroid, place the point of your probe to the pad for the lead of the very left torroid. Hold your probe hand steady and turn on the K2, placing it on 80m. For all these tests, set your power out to 1 Watt. Now press TUNE, notice the internal meter on your K2 compared to the external meter reading. If you see Hi Cur, get out of the TUNE mode. Don't stay in the TUNE mode too long (5-10 seconds). Now with the K2 off, move your probe point to the very right torroid's lead, test the same thing. You should see that you get a blurry signal on the very left torroid and a clean signal on the very right torroid. NOW HERE IS THE TEST TO FIND A BAD RELAY THAT IS NOT WORKING IN THE LPF SECTION. [With RX set to 80m, then set to TUNE mode, you are looking for a relay in the LPF that should not be active {meaning no RF on the input or output on the relay for another band, that is not selected on the RX display of the K2}, if it is active than that relay(s) needs to be replaced. Only 80m should have RF output on its relay and no other relay.] After doing the tests mentioned above, turn off the K2 and replace your probe point as discussed above in checking the LPF for the next band. Turn on your K2, still on 80m RX, go into the TUNE mode and look to see that THERE SHOULD BE NO RF AT ALL. Then check the very right torroid for that band different from the RX band, 80m. THERE SHOULD BE NO RF AT ALL there also. Get out of TUNE mode. Do these steps for every relay in the LPF pertaining to a different band than 80m. If you find bad relays, replace them. This should bring your power back up. You will have to redo the BPF alignment, to get full power out on all bands. Remember while waiting for the relay replacements not to use the bands without relays. You can use the other bands, but DON'T TX on bands without a relay. This information is an accumulation of thoughts from the Elecraft team, et Gary Surrency. If you are having anymore problems, or this information did not help you contact Gary at: gary at elecraft.com Also check everything in the LPF and the rest of the board for torroid spacing adjustments, missed soldering a pad, cold grayish color soldering points. Check Q7 and Q8 with the K2 off, for high impedance on the B & C leads, and a short to GND on the E lead, if so your PA transistors are good. Check T1-T4 transformers on the last sheet of schematics for the RF board, for proper winding, tinning of leads, and placement of the red/white/green leads. Make sure these are wound according to the book. Daniel kg4dni ++++++++++++++++++