RF Probe again
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I have a RF probe. However I am not sure it is working. It did not seem
to work at the first test point I tried. Is there someplace in the K2 on the receive side I could test it? My problem appears to be in the send side. This obviously would eliminate some problems if it worked. Gary WA4SZI _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Gary,
Turn your manual to the Troubleshooting Appendix - look at page 10 near the end and you will find the PLL and VCO circuits will provide you with some checks for your RF Probe. 73, Don W3FPR Gary Montalbine wrote: > I have a RF probe. However I am not sure it is working. It did not seem > to work at the first test point I tried. Is there someplace in the K2 on > the receive side I could test it? My problem appears to be in the send > side. This obviously would eliminate some problems if it worked. > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Thanks all for the response. My RF probe works at TP1 and the PLL and
VCO circuits. U8 was where I had no voltage and was unsure of the probe. Need to check further. Gary, WA4SZI Don Wilhelm wrote: > Gary, > > Turn your manual to the Troubleshooting Appendix - look at page 10 near > the end and you will find the PLL and VCO circuits will provide you with > some checks for your RF Probe. > > 73, > Don W3FPR > > Gary Montalbine wrote: >> I have a RF probe. However I am not sure it is working. It did not >> seem to work at the first test point I tried. Is there someplace in >> the K2 on the receive side I could test it? My problem appears to be >> in the send side. This obviously would eliminate some problems if it >> worked. >> > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Gary,
I must be misreading something or you had a typo. RF Board U8 is a voltage regulator - you will not find any RF there. 73, Don W3FPR Gary Montalbine wrote: > Thanks all for the response. My RF probe works at TP1 and the PLL and > VCO circuits. U8 was where I had no voltage and was unsure of the probe. > Need to check further. > > Gary, WA4SZI > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Basic problem was engage mind before typing. High DC voltage at U8 and
no RF voltage at pin 4 of U10. Low RF voltage at pin 6 of U9. Wanted to make sure my RF probe was good before continuing. It has been many years since I have messed with electronic circuits.I may be back at the Novice level. Would this be the appropriate forum to address my transmitting problems or should I bother Gary? I appreciate everybodys help thus far. Gary, WA4SZI K2 #1009 Don Wilhelm wrote: > Gary, > > I must be misreading something or you had a typo. RF Board U8 is a > voltage regulator - you will not find any RF there. > > 73, > Don W3FPR > > Gary Montalbine wrote: >> Thanks all for the response. My RF probe works at TP1 and the PLL and >> VCO circuits. U8 was where I had no voltage and was unsure of the >> probe. Need to check further. >> >> Gary, WA4SZI >> > _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Gary does not work weekends, and you can likely have it isolated by then.
If you have no output from U10-4, then how about the input at pin 1? That should be the BFO signal fed to the transmit mixer. (you do have the KSB2 plugged in correctly do you not?). The only other signal that must be present is the TX VFO which should have at least 70 mV RF on U10 pin 6. You must be in TUNE or otherwise keydown to get RF to U10-1. If you have RF at both U10-1 and U10-6, you shoudl also have RF at U10-4. Check the DC voltage at pin 8 (it will only be present during TUNE or other transmit periods). 73, Don W3FPR Gary Montalbine wrote: > Basic problem was engage mind before typing. High DC voltage at U8 and > no RF voltage at pin 4 of U10. Low RF voltage at pin 6 of U9. Wanted to > make sure my RF probe was good before continuing. It has been many years > since I have messed with electronic circuits.I may be back at the Novice > level. Would this be the appropriate forum to address my transmitting > problems or should I bother Gary? > > I appreciate everybodys help thus far. > > Gary, WA4SZI > > K2 #1009 > > > > Don Wilhelm wrote: >> Gary, >> >> I must be misreading something or you had a typo. RF Board U8 is a >> voltage regulator - you will not find any RF there. >> >> 73, >> Don W3FPR >> >> Gary Montalbine wrote: >>> Thanks all for the response. My RF probe works at TP1 and the PLL and >>> VCO circuits. U8 was where I had no voltage and was unsure of the >>> probe. Need to check further. >>> >>> Gary, WA4SZI >>> >> > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 mailing list Post to: [hidden email] 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 |
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Don Wilhelm wrote:
> Gary does not work weekends, and you can likely have it isolated by then. > > If you have no output from U10-4, then how about the input at pin 1? > That should be the BFO signal fed to the transmit mixer. (you do have > the KSB2 plugged in correctly do you not?). Pin 1 also reads 0. Per the troubleshooting instructions the KSB2 was removed. I installed temporary jumper pins between 1 & 3 of J9 and J10 and installed a .001mf cap between pins 7 & 12 of J11. I can reinstall KSB2 if you think it will help. The only other signal that > must be present is the TX VFO which should have at least 70 mV RF on U10 > pin 6. I have .16V You must be in TUNE or otherwise keydown to get RF to U10-1. Tried both. > > If you have RF at both U10-1 and U10-6, you shoudl also have RF at > U10-4. Check the DC voltage at pin 8 (it will only be present during > TUNE or other transmit periods). Pin 8 voltage is 6V in tune. Thanks, Gary WA4SZI > > 73, > Don W3FPR > > Gary Montalbine wrote: >> Basic problem was engage mind before typing. High DC voltage at U8 and >> no RF voltage at pin 4 of U10. Low RF voltage at pin 6 of U9. Wanted >> to make sure my RF probe was good before continuing. It has been many >> years since I have messed with electronic circuits.I may be back at >> the Novice level. Would this be the appropriate forum to address my >> transmitting problems or should I bother Gary? >> >> I appreciate everybodys help thus far. >> >> Gary, WA4SZI >> >> K2 #1009 Elecraft mailing list Post to: [hidden email] 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 |
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Gary,
You should have signal at U10 pin 1 but you don't - you had a signal at the BFO output if I recall correctly, so something is broken between those two points. Since you jumpered the KSB2 headers correctly, leave things that way for now. Set the K2 to TUNE and recheck to be certain you have RF at the following points (in order): U11 pin 6 Q24 gate TP2 D36 anode (small fragile glass diode on the bottom of the board) D36 cathode J11 pin 12 J11 pin 7 U10 pin 1 That is the entire path between the BFO and the transmit mixer input, and you should be able to locate the point where the signal disappears. 73, Don W3FPR Gary Montalbine wrote: > Don Wilhelm wrote: >> Gary does not work weekends, and you can likely have it isolated by then. >> >> If you have no output from U10-4, then how about the input at pin 1? >> That should be the BFO signal fed to the transmit mixer. (you do have >> the KSB2 plugged in correctly do you not?). > > Pin 1 also reads 0. Per the troubleshooting instructions the KSB2 was > removed. I installed temporary jumper pins between 1 & 3 of J9 and J10 > and installed a .001mf cap between pins 7 & 12 of J11. I can reinstall > KSB2 if you think it will help. > > The only other signal that >> must be present is the TX VFO which should have at least 70 mV RF on >> U10 pin 6. > > I have .16V > > You must be in TUNE or otherwise keydown to get RF to U10-1. > > Tried both. >> >> If you have RF at both U10-1 and U10-6, you shoudl also have RF at >> U10-4. Check the DC voltage at pin 8 (it will only be present during >> TUNE or other transmit periods). > > Pin 8 voltage is 6V in tune. > > Thanks, > > Gary WA4SZI >> >> 73, >> Don W3FPR >> >> Gary Montalbine wrote: >>> Basic problem was engage mind before typing. High DC voltage at U8 >>> and no RF voltage at pin 4 of U10. Low RF voltage at pin 6 of U9. >>> Wanted to make sure my RF probe was good before continuing. It has >>> been many years since I have messed with electronic circuits.I may be >>> back at the Novice level. Would this be the appropriate forum to >>> address my transmitting problems or should I bother Gary? >>> >>> I appreciate everybodys help thus far. >>> >>> Gary, WA4SZI >>> >>> K2 #1009 > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 mailing list Post to: [hidden email] 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 |
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Don Wilhelm wrote:
> Gary, > > You should have signal at U10 pin 1 but you don't - you had a signal at > the BFO output if I recall correctly, so something is broken between > those two points. > > Since you jumpered the KSB2 headers correctly, leave things that way for > now. > > Set the K2 to TUNE and recheck to be certain you have RF at the > following points (in order): > U11 pin 6 .36V > Q24 gate .04V Rest are all 0V. The voltage was present at U11 and Q24 without going into tune. The voltages did not change in tune. Don't know if this is significant. Q24 D shows an input from V ALC. I cannot find this source. Voltage on D is 0. The DC voltage table shows that the following transmit-mode voltages for Q24 should be G - 0, S - 1.2, D 1.3. I got the following DC voltage with key down, not RF probe, G - 0, S - .86, D .94. Would replacement of Q24 be in order? > TP2 > D36 anode (small fragile glass diode on the bottom of the board) > D36 cathode > J11 pin 12 > J11 pin 7 > U10 pin 1 > > That is the entire path between the BFO and the transmit mixer input, > and you should be able to locate the point where the signal disappears. > > > Gary Montalbine wrote: >> Don Wilhelm wrote: >>> Gary does not work weekends, and you can likely have it isolated by >>> then. >>> >>> If you have no output from U10-4, then how about the input at pin 1? >>> That should be the BFO signal fed to the transmit mixer. (you do have >>> the KSB2 plugged in correctly do you not?). >> >> Pin 1 also reads 0. Per the troubleshooting instructions the KSB2 was >> removed. I installed temporary jumper pins between 1 & 3 of J9 and J10 >> and installed a .001mf cap between pins 7 & 12 of J11. I can reinstall >> KSB2 if you think it will help. >> >> The only other signal that >>> must be present is the TX VFO which should have at least 70 mV RF on >>> U10 pin 6. >> >> I have .16V >> >> You must be in TUNE or otherwise keydown to get RF to U10-1. >> >> Tried both. >>> >>> If you have RF at both U10-1 and U10-6, you shoudl also have RF at >>> U10-4. Check the DC voltage at pin 8 (it will only be present during >>> TUNE or other transmit periods). >> >> Pin 8 voltage is 6V in tune. >> >> Thanks, >> >> Gary WA4SZI >>> >>> 73, > Elecraft mailing list Post to: [hidden email] 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 |
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Gary,
Possibly Q24 could need replaced, but it is too quick to judge. Certainly V ALC is not up to the normal DC level - BTW, that listed voltage is nominal for a setting of 5 watts out with the K2 actually delivering 5 watts. Since you have no power out, the voltage on V ALC should be quite a bit higher. If the K2 senses no ouput, the V ALC voltage should increase in an effort to increase the power - that is not happening in your case. V ALC comes from the Control Board - the emitter of Q8 drives that signal. Check the 2 capacitors added on the back of the Control Board (this circuit deals with the keying waveshape control). With the information you have provided so far, Control Board U10A, Q8 and their associated components are the prime suspects. 73, Don W3FPR Gary Montalbine wrote: > Don Wilhelm wrote: >> Gary, >> >> You should have signal at U10 pin 1 but you don't - you had a signal >> at the BFO output if I recall correctly, so something is broken >> between those two points. >> >> Since you jumpered the KSB2 headers correctly, leave things that way >> for now. >> >> Set the K2 to TUNE and recheck to be certain you have RF at the >> following points (in order): >> U11 pin 6 > > .36V >> Q24 gate > .04V > > Rest are all 0V. The voltage was present at U11 and Q24 without going > into tune. The voltages did not change in tune. Don't know if this is > significant. > > Q24 D shows an input from V ALC. I cannot find this source. Voltage on D > is 0. The DC voltage table shows that the following transmit-mode > voltages for Q24 should be G - 0, S - 1.2, D 1.3. I got the following DC > voltage with key down, not RF probe, G - 0, S - .86, D .94. > > Would replacement of Q24 be in order? > Elecraft mailing list Post to: [hidden email] 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 |
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