Re: [Elecraft] dead K2
On 6/21/2024 11:24 AM, Oscar Castillo wrote: hello everyone, , the coaxial that carries the RF from the board to the tunner was loose (the ground part of the coax was broken), in the physical inspection everything looks fine, no "pop" was heard, There was no smoke anywhere or a burning smell, so I have no idea where to start, any advice would be greatly appreciated. It's been a long time since I sold my K2s, but I have more recent experience with K3s, and I had a problem with one of those mini-coax jumpers. Elecraft can send some to you. And if it's a female connector that solders to a board, they can send you that. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] dead K2
Oscar, First remove the KAT2 from the K2 entirely, including the cable to the control board. Then connect a dummy load to the BNC on the lower rear panel. Try transmitting (do a TUNE) and see if there is any RF. If there is, you are fortunate, fix the coax ground to the KAT2 and put it back together. If not, you have some troubleshooting to do. Get an RF Probe (or an oscilloscope) and follow the procedure for troubleshooting that is printed near the back of the K2 manual (download if you do not have a printed copy). Until you find the failure point, that is all I can tell you. A serial number will be helpful. You might also contact Elecraft support, and Dave W8FGU can likely help as well - he is the official contact for support on the legacy gear (K1, K2, KX1). 73, Don W3FPR On 6/21/2024 2:24 PM, Oscar Castillo wrote: hello everyone, Several years ago I bought my K2 and I have been very happy since then, but a month ago tragedy struck my life. I noticed that the radio was "deaf", so I did a tuning cycle and my radio turned off completely, I checked everything on the outside and it looked good, I checked the power and it was fine (13.2 v), the antenna was fine, so I removed the top cover and that was where I saw the "big problem", the coaxial that carries the RF from the board to the tunner was loose (the ground part of the coax was broken), in the physical inspection everything looks fine, no "pop" was heard, There was no smoke anywhere or a burning smell, so I have no idea where to start, any advice would be greatly appreciated. I bought the radio assembled and it has the following modules KAF2 KSB2 KNB2 K160M KIO2 KAT2 I really hope that you guys cand help me, it´s hard to find a place to fix it here in Mexico, and the shipping cost to send it to the US are really high. best regards to all of you Oscar XE2IF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] dead K2
hello everyone, Several years ago I bought my K2 and I have been very happy since then, but a month ago tragedy struck my life. I noticed that the radio was "deaf", so I did a tuning cycle and my radio turned off completely, I checked everything on the outside and it looked good, I checked the power and it was fine (13.2 v), the antenna was fine, so I removed the top cover and that was where I saw the "big problem", the coaxial that carries the RF from the board to the tunner was loose (the ground part of the coax was broken), in the physical inspection everything looks fine, no "pop" was heard, There was no smoke anywhere or a burning smell, so I have no idea where to start, any advice would be greatly appreciated. I bought the radio assembled and it has the following modules KAF2 KSB2 KNB2 K160M KIO2 KAT2 I really hope that you guys cand help me, it´s hard to find a place to fix it here in Mexico, and the shipping cost to send it to the US are really high. best regards to all of you Oscar XE2IF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] dead K2
Mike, My K2/100 #3255 behaved in exactly the same way some years ago, actually on two occasions about a year apart. The problem was caused by dirt or corrosion on the contacts of the socket of the MCU U6 on the Control board. Pulling and reseating the U6 IC cured the problem on each occasion. After the second episode I changed U6's socket to a turned pin (machined) type of socket, and the problem has not reared its ugly head since. The type of socket supplied with the K2 kit is often a cause of "problems". 73, Geoff GM4ESD From: "worsr" Sent: Friday, May 07, 2010 9:47 PM > My K2 #5767 suddenly has quit working. Upon power up today, the freq. > readout is OK, but none of the buttons work and the tuning dial doesn't > change freq. No error messages are seen at powerup. > > Anyone have any ideas?? > > --Mike, W0RSR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] dead K2
Mike, The symptom of not being able to do anything from the front panel is usually an indication that it is attempting to transmit as soon as power is applied. The simple thing that can cause a transmit condition is a closed key (or PTT). Remove anything from the micophone jack, remove anything from the key jack and the AUX I/O if you have one. Connect a dummy load 'just in case' my transmit assumption is correct. If you have the KPA100, it is preferable to power only the base K2, but if you have only the 12 volt cable for the KPA100, go ahead and use it. After that bit of setup, power the K2 on - does it work? If so, one of the external cables was putting it into transmit, your task is to find which one and correct it. If you still have the same problem, remove the top cover (whether that be the KPA100 or the QRP cover. You will be making a couple checks with your DMM. Power on and check the voltage at the anode of both D6 and D7 (located halfway back about 1 inch from the left side panel). During receive, you should find the anode of D6 near 8 volts and the anode of D7 near zero - during transmit, the anode of D6 should go to zero and the anode of D7 will be near 8 volts. If both of them are near 8 volts when you power on, power off quickly and tell us about it. In any case tell us what you found in the above steps before proceeding further (or making any assumptions). An orderly progression of tests will lead you to the failure point. 73, Don W3FPR worsr wrote: > My K2 #5767 suddenly has quit working. Upon power up today, the freq. > readout is OK, but none of the buttons work and the tuning dial doesn't > change freq. No error messages are seen at powerup. > > Anyone have any ideas?? > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] dead K2
My K2 #5767 suddenly has quit working. Upon power up today, the freq. readout is OK, but none of the buttons work and the tuning dial doesn't change freq. No error messages are seen at powerup. Anyone have any ideas?? --Mike, W0RSR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] Dead K2/100
What should the resistances between poles of Q7 & Q8 be? Mac __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
Fred, We are 'doubling' with overlapping posts here along with fast paced responses. From that brief measurement, I think Q3 is the problem - I base that on the fact that you measure 8 volts on both D6 and D7. Just remove Q3 to check that theory. The K2 will receive without Q3 installed, but will get mixed up if you try to transmit. If you get receive and a display with Q3 removed, then a new 2N7000 should fix it. BTW, you cannot check a transistor or FET for short/open by making resistance measurements - it is just not reliable nor predictable. 73, Don W3FPR KC9QQ wrote: > > KC9QQ wrote: > >> >> Don Wilhelm-4 wrote: >> >>> Fred, >>> >>> In cases like yours, first step is to connect a dummy load to the K2 >>> just in case it is trying to transmit - it is not good to enter transmit >>> state without a load on the PA transistors. If it is a K2/100, remove >>> the KPA100 and connect the dummy load to the BNC antenna jack on the >>> lower rear panel. >>> >>> First thing is to check the state of the 8T and 8R voltage rails. Those >>> are easily checked at the anodes of D6 and D7. If D7 anode has 8 volts >>> on it while D6 anode has zero volts, then the K2 is in a transmit >>> state. If both D7 and D6 anodes have 8 volts present, power it only >>> briefly while making further checks lest some components overheat. >>> >>> If both 8T and 8R are present, you need to check the state of the RX >>> signal at the gate of control board Q4 as well as the TX signal at the >>> gate of CB Q3 - one should be on (about 5 volts) while the other should >>> be off (near zero volts). If both of these are on, the microprocessor >>> was zapped with the power surge, but if only one is on, the problem is a >>> shorted Q3 or Q4 on the control board. >>> >>> 73, >>> Don W3FPR >>> >>> >>> >>> >>> >> Don, >> >> I pulled the control board again to reset the relays and then reinstalled >> it to make the measurements on D6 and D7. When I powered the unit, >> Elecraft was again shown and the frequency of 7100 was briefly displayed. >> When then display went out I measured the anodes and cathodes of both d6 >> and d7 and measured nearly zero volts on both. >> >> > > I tested the voltages on D6 and D7 anodes again when I powered up. I had to > power up twice, but each showed around 7 volts before they fell to near > zero. I have found that I can let the unit sit for a few minutes before I > re-power and I don't have to pull the control board to reset the relays. > This only gives me about 2 seconds to make the measurement. > The voltage on the gate of Q4 is 5 volts. The voltage on the Gate of Q3 is > close to zero for the brief period I have to make the measurement. After a > few moments the gate of Q4 drops to zero. > > How do I tell which is shorted? I made the following measurements to > resistance measurements referenced to ground. > > Q3 > S - 0.4 M > G - 5.4 M > D - 8.1 M > > Q4 > S - 0.3 ohms > G - 3.9 K ohms > D - 8.1 K ohms > > I am assuming the culprit is Q4. Am I correct? Is it possible the > something else is fried that may take out Q4 if I install a replacement? I > still have 4 boards that I have not built (SSB, DSP2, AT and NB). I > believe at least one of these has a 2N7000 I can rob for a temporary > replacement. I just don't want to install it until I am sure another > failure somewhere else upstream won't cause it to fail. Are there any other > items I should check before I replace the failed transistor? > > Thanks, > > Fred > > > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
Fred, Zero volts on both is way better than 8 volts on both - at least the K2 is not trying to transmit. Check the gates of Q3 and Q4 on the control board. The gate of Q4 should be at 5 volts and the gate of Q3 should be near zero. If that is true (and only if that is true), short the drain of Q4 to its source and see if the 8R voltage rail comes to life - 8 volts at the anode of D6. If so, replace Q4. If still no 8 volts on 8R, then something is wrong with Q2 (likely open). OTOH, if the gates of both Q3 and Q4 are near zero volts, you have a bad microprocessor output. 73, Don W3FPR PS: Top posting is preferred here, it is easier to see the latest without scrolling all the way to the bottom - on some posts it is hard to determine what has been added - I know about 'netiquette', but that is slow and laborious. KC9QQ wrote: > > Don Wilhelm-4 wrote: > >> Fred, >> >> In cases like yours, first step is to connect a dummy load to the K2 >> just in case it is trying to transmit - it is not good to enter transmit >> state without a load on the PA transistors. If it is a K2/100, remove >> the KPA100 and connect the dummy load to the BNC antenna jack on the >> lower rear panel. >> >> First thing is to check the state of the 8T and 8R voltage rails. Those >> are easily checked at the anodes of D6 and D7. If D7 anode has 8 volts >> on it while D6 anode has zero volts, then the K2 is in a transmit >> state. If both D7 and D6 anodes have 8 volts present, power it only >> briefly while making further checks lest some components overheat. >> >> If both 8T and 8R are present, you need to check the state of the RX >> signal at the gate of control board Q4 as well as the TX signal at the >> gate of CB Q3 - one should be on (about 5 volts) while the other should >> be off (near zero volts). If both of these are on, the microprocessor >> was zapped with the power surge, but if only one is on, the problem is a >> shorted Q3 or Q4 on the control board. >> >> 73, >> Don W3FPR >> >> Fred Keller wrote: >> >>> I also just noticed that the power output transistors Q7 and Q8 are >>> getting warm when the power is on. I did not say before but, their >>> is no display or any other activity on the control board or front panel. >>> >>> Fred, KC9QQ >>> >>> > Don, > > I pulled the control board again to reset the relays and then reinstalled it > to make the measurements on D6 and D7. When I powered the unit, Elecraft > was again shown and the frequency of 7100 was briefly displayed. When then > display went out I measured the anodes and cathodes of both d6 and d7 and > measured nearly zero volts on both. > > Fred > > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
KC9QQ wrote: > > > > Don Wilhelm-4 wrote: >> >> Fred, >> >> In cases like yours, first step is to connect a dummy load to the K2 >> just in case it is trying to transmit - it is not good to enter transmit >> state without a load on the PA transistors. If it is a K2/100, remove >> the KPA100 and connect the dummy load to the BNC antenna jack on the >> lower rear panel. >> >> First thing is to check the state of the 8T and 8R voltage rails. Those >> are easily checked at the anodes of D6 and D7. If D7 anode has 8 volts >> on it while D6 anode has zero volts, then the K2 is in a transmit >> state. If both D7 and D6 anodes have 8 volts present, power it only >> briefly while making further checks lest some components overheat. >> >> If both 8T and 8R are present, you need to check the state of the RX >> signal at the gate of control board Q4 as well as the TX signal at the >> gate of CB Q3 - one should be on (about 5 volts) while the other should >> be off (near zero volts). If both of these are on, the microprocessor >> was zapped with the power surge, but if only one is on, the problem is a >> shorted Q3 or Q4 on the control board. >> >> 73, >> Don W3FPR >> >> >> >> > > Don, > > I pulled the control board again to reset the relays and then reinstalled > it to make the measurements on D6 and D7. When I powered the unit, > Elecraft was again shown and the frequency of 7100 was briefly displayed. > When then display went out I measured the anodes and cathodes of both d6 > and d7 and measured nearly zero volts on both. > I tested the voltages on D6 and D7 anodes again when I powered up. I had to power up twice, but each showed around 7 volts before they fell to near zero. I have found that I can let the unit sit for a few minutes before I re-power and I don't have to pull the control board to reset the relays. This only gives me about 2 seconds to make the measurement. The voltage on the gate of Q4 is 5 volts. The voltage on the Gate of Q3 is close to zero for the brief period I have to make the measurement. After a few moments the gate of Q4 drops to zero. How do I tell which is shorted? I made the following measurements to resistance measurements referenced to ground. Q3 S - 0.4 M G - 5.4 M D - 8.1 M Q4 S - 0.3 ohms G - 3.9 K ohms D - 8.1 K ohms I am assuming the culprit is Q4. Am I correct? Is it possible the something else is fried that may take out Q4 if I install a replacement? I still have 4 boards that I have not built (SSB, DSP2, AT and NB). I believe at least one of these has a 2N7000 I can rob for a temporary replacement. I just don't want to install it until I am sure another failure somewhere else upstream won't cause it to fail. Are there any other items I should check before I replace the failed transistor? Thanks, Fred Fred Fred -- View this message in context: http://n2.nabble.com/Dead-K2-After-nearby-power-surge-tp2312857p2313061.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
Don Wilhelm-4 wrote: > > Fred, > > In cases like yours, first step is to connect a dummy load to the K2 > just in case it is trying to transmit - it is not good to enter transmit > state without a load on the PA transistors. If it is a K2/100, remove > the KPA100 and connect the dummy load to the BNC antenna jack on the > lower rear panel. > > First thing is to check the state of the 8T and 8R voltage rails. Those > are easily checked at the anodes of D6 and D7. If D7 anode has 8 volts > on it while D6 anode has zero volts, then the K2 is in a transmit > state. If both D7 and D6 anodes have 8 volts present, power it only > briefly while making further checks lest some components overheat. > > If both 8T and 8R are present, you need to check the state of the RX > signal at the gate of control board Q4 as well as the TX signal at the > gate of CB Q3 - one should be on (about 5 volts) while the other should > be off (near zero volts). If both of these are on, the microprocessor > was zapped with the power surge, but if only one is on, the problem is a > shorted Q3 or Q4 on the control board. > > 73, > Don W3FPR > > Fred Keller wrote: >> I also just noticed that the power output transistors Q7 and Q8 are >> getting warm when the power is on. I did not say before but, their >> is no display or any other activity on the control board or front panel. >> >> Fred, KC9QQ >> >> > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > Don, I pulled the control board again to reset the relays and then reinstalled it to make the measurements on D6 and D7. When I powered the unit, Elecraft was again shown and the frequency of 7100 was briefly displayed. When then display went out I measured the anodes and cathodes of both d6 and d7 and measured nearly zero volts on both. Fred -- View this message in context: http://n2.nabble.com/Dead-K2-After-nearby-power-surge-tp2312857p2312974.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
Fred, In cases like yours, first step is to connect a dummy load to the K2 just in case it is trying to transmit - it is not good to enter transmit state without a load on the PA transistors. If it is a K2/100, remove the KPA100 and connect the dummy load to the BNC antenna jack on the lower rear panel. First thing is to check the state of the 8T and 8R voltage rails. Those are easily checked at the anodes of D6 and D7. If D7 anode has 8 volts on it while D6 anode has zero volts, then the K2 is in a transmit state. If both D7 and D6 anodes have 8 volts present, power it only briefly while making further checks lest some components overheat. If both 8T and 8R are present, you need to check the state of the RX signal at the gate of control board Q4 as well as the TX signal at the gate of CB Q3 - one should be on (about 5 volts) while the other should be off (near zero volts). If both of these are on, the microprocessor was zapped with the power surge, but if only one is on, the problem is a shorted Q3 or Q4 on the control board. 73, Don W3FPR Fred Keller wrote: > I also just noticed that the power output transistors Q7 and Q8 are > getting warm when the power is on. I did not say before but, their > is no display or any other activity on the control board or front panel. > > Fred, KC9QQ > > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2 After nearby power surge
KC9QQ wrote: > > I also just noticed that the power output transistors Q7 and Q8 are > getting > warm when the power is on. I did not say before but, their is no display > or any other activity on the control board or front panel. > > Fred, KC9QQ > > > > > ___ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > I also just notice that the transistors Q7 and Q8 are getting warm when the unit is powered. Even though the display is dead. Fred -- View this message in context: http://n2.nabble.com/Dead-K2-After-nearby-power-surge-tp2312857p2312876.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] Dead K2 After nearby power surge
I also just noticed that the power output transistors Q7 and Q8 are getting warm when the power is on. I did not say before but, their is no display or any other activity on the control board or front panel. Fred, KC9QQ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Dead K2-now lives!
Many thanks to all who replied to my question. What happened was that while I was putting T4 on, I overheated the 7-8 winding and it melted through the insulation of the 3-4 winding, therefore shorting it. So I just rewound it and it works! Thanks again! 73, Kristina KE7LUC ___ 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] Dead K2
Kristina, You will just have to continue measuring things until you discover the root cause. Did you measure the resistance at the power plug with the power switch ON? Try the checks below (in order until you find the source). Measure the resistance to ground from the cathode of D12. You may find it quite low (indicating a short). Remove the control board and check it again - if the resistance increases, look for the problem on the control board. If not on the control board, remove the heat sink and then recheck - if things are OK with the heat sink removed, check the thermal pads. If you still have not found it, the 'hunting' gets more difficult. Use the schematic to follow the path of the 12V voltage line - it starts at the lower right corner of RF Board sheet 1, and goes to the regulators on the control board, and various places on the RF Board (mostly on sheet 4). Check those paths thoroughly, even if it means removing some components to see which side of the component the short is located. Remember that the most likely cause is a solder bridge (connecting 2 points that should not connect together) so a VERY careful visual inspection may reveal the problem source. Work in an orderly manner - a short on a power line is difficult to find because the PC traces seem to go everywhere and it is difficult to isolate them - expect some frustration in the process. 73, Don W3FPR Kristina Wright wrote: OK, here's what I've done so far: checked the resistance from the power plug to ground, the meter read infinite resistance. Also checked the voltage at the same and got 12 volts. Then I measured the voltage at the cathode end of D10 and got 12 volts with the power switch on and off, but at D12 I got nothing with the power off and 0.7 volts with it on. Obviously the fuse is being tripped, but I still don't see any shorts (yes I inspected the whole board carefully). Thanks for the help so far, any more ideas? 73, Kristina, KE7LUC ___ 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] Dead K2
OK, here's what I've done so far: checked the resistance from the power plug to ground, the meter read infinite resistance. Also checked the voltage at the same and got 12 volts. Then I measured the voltage at the cathode end of D10 and got 12 volts with the power switch on and off, but at D12 I got nothing with the power off and 0.7 volts with it on. Obviously the fuse is being tripped, but I still don't see any shorts (yes I inspected the whole board carefully). Thanks for the help so far, any more ideas? 73, Kristina, KE7LUC Jim, <[EMAIL PROTECTED]> wrote: Check the voltage at the power connector when it is dead and see if you have 12 volts there. Also check on the other side of the resetable fuse on the right side of the rf board and make sure it is not opening up. A good place to check the voltage is at the cathode end of the big power diode on the right side of the rf board. and at the pins of the on/off switch. Jim K4ZM Don Wilhelm <[EMAIL PROTECTED]> wrote: OK, check the resistance from the coaxial power plug to ground both with the switch on and with it off. If you find the resistance at 500 ohms or more, then the K2 is likely OK, check your power supply and cord for good solid connections - you are using a proper regulated power supply rated at 3 amps or greater are you not? If all is OK there, measure the voltage at D10 cathode and D12 cathode (with the power turned on - of course). 73, Don W3FPR ___ 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] Dead K2
Nothing I can see looks to be shorted. And yes I checked the collectors of Q7 and Q8 and it was 1.6 k ohms, so the problem doesn't seem to be there. I'll go fiddle with it some more. Kristina, KE7LUC On 5/24/07, Don Wilhelm <[EMAIL PROTECTED]> wrote: Kristina, It sounds like you have created a short in the DC power and the resettable fuse is being activated. Check all your soldering and the pad placement of the thermal pads for the PA transistors. Did you check for a short at the collectors of Q7 and Q8 as instructed? If so, what was your resistance reading. 73, Don W3FPR ___ 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] Dead K2
Kristina, It sounds like you have created a short in the DC power and the resettable fuse is being activated. Check all your soldering and the pad placement of the thermal pads for the PA transistors. Did you check for a short at the collectors of Q7 and Q8 as instructed? If so, what was your resistance reading. 73, Don W3FPR Kristina Wright wrote: Hi all, In building my K2 everything has gone perfectly and without a hitch until I got to the Alignment and Test, Part III. When I try to turn it on there's an audio "pop" but nothing on the LCD display and no relays clicking. It worked just fine before I installed the transmitter part. Its probably something simple, but I don't know what. Any ideas?? 73, Kristina, KE7LUC ___ 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
[Elecraft] Dead K2
Hi all, In building my K2 everything has gone perfectly and without a hitch until I got to the Alignment and Test, Part III. When I try to turn it on there's an audio "pop" but nothing on the LCD display and no relays clicking. It worked just fine before I installed the transmitter part. Its probably something simple, but I don't know what. Any ideas?? 73, Kristina, KE7LUC ___ 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
[Elecraft] dead K2 is alive no
Hi everyone and thanks everyone for answering "to my dead K2 on 3,5 and 7,0" the K2 is alive and the owner is reading the op.manual very very closley ! 73 de Rolf SM2MZC ___ 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
