Re: # 4472 mixer problem now???
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Hello all,
Just took some voltage readings. Q 22 base 1.894 emitter 1.168 collector 10.88 Z6 mixer 0 volts on all 4 pins.. it that correct??? Q21 base and emitter 0 volts collector 11.78 ( PRE amp is not on) D7 and D6 junction 7.24 D6 anode 7.87 Can anyone make sense of this.. Do I have a bad mixer? Since the freq looks incorrect also. Jerry Below is my older post. ***************************************************************************** New problem is on the IF amp alignment page 64 in manual. I get just very little hiss with headphones with the AF gain to max and can't even hear the internaly - generated signal I even hooked up an antenna and could not hear any signals. I tried tweaking L1 and L2 to no avail... I was afraid to tweak them to much. I then tried hooking up the headphone output to the computer mic in ( no display at all on line in) using Spectorgram and had noise displayed but no trace of a signal , by the way the mic gain was in the middle. Then i tried tweaking L1 and L2 but could see no change. Should I be able to see the internally generated signal with spectrogram? Every adjusment on pages 60 to 63 went ok. Just got my XG! test occilator today and put it together tonite and did a little troubleshooting. I have the K2 set for 7040 Khz and the XG1 on 50uv and i am getting at the W2 jumper a 42 mv p-p 11955khz signal (using a scope and the internal freq counter). There is nothing at the W3 jumper, not getting thur the crystal filter. BUT, should not that be a 4.9136 IF signal? I get the same freq signal at the collector of Q22, the post-mixer amp *************************************************************************************************************************************************** jerry [hidden email] 2004-10-28 _______________________________________________ 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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My just completed #4438 with SSB, DSP, 160M, and 100Watt Modules
seems to be working just fine .... except: .. on the low end of 80 meters (3500-3700 approximatly) the signal sounds like there is a 'ringing' on it when listening to another receiver in the shack. This happens only at power levels above about 50 watts and only on the low end of 80 meters. Here is what I have done: Replaced my power supply with a large lead-acid car battery to eliminate any possibility of interaction with the power supply. Results the same with either power source. Tried two different monitoring receivers ... same results with each. I am using a 50 ohm dummy load (Heath Cantenna). This is what I see: A scope looking at the RF waveform shows NO am modulation. The envelope is clean. A scope looking at the RF waveform does show a slight blurriness in the horizontal axis indicating rapid but slight frequency shift. A scope monitoring the 12 volt input shows a small sinusoid waveform on the 12 volt input (a hundred mV or so) indicating that there is a significant AC component of current being drawn from the battery. The frequency of this AC component of input current is about 30 hertz. I suspect ALC instability of some kind. I could sure use some help here. Don K7FJ _______________________________________________ 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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This sounds like the same I'm trying to cure here also.
I did have FM-ing on 80 with dummy , but not with antenna. My antenna is groundmounted and with radials so it's grounded. What happens if u try the antenna with ground? And if u set power to 50 watt on 80 meter and switch to 40 and wistle high tone/pitch in the mic , does your power go way up then? I have a problem where the K2/100 forget powersetting and want regulate down on it self. This happens partly on 80 also. But a low wistle in the mic in same time as I regulate down power does work and it stays there until I change band again. Can you try that? I'm interested to hear if you have same symptom? Good luck! 73 Tom LA1PHA ----- Original Message ----- From: "Don Ehrlich" <[hidden email]> To: <[hidden email]>; <[hidden email]> Sent: Thursday, October 28, 2004 6:27 PM Subject: [Elecraft] K2 FM-ing on 80 Meters > My just completed #4438 with SSB, DSP, 160M, and 100Watt Modules seems to > be working just fine .... except: > > .. on the low end of 80 meters (3500-3700 approximatly) the signal sounds > like there is a 'ringing' on it when listening to another receiver in the > shack. This happens only at power levels above about 50 watts and only on > the low end of 80 meters. > > Here is what I have done: > > Replaced my power supply with a large lead-acid car battery to eliminate > any possibility of interaction with the power supply. Results the same > with either power source. > > Tried two different monitoring receivers ... same results with each. > > I am using a 50 ohm dummy load (Heath Cantenna). > > > This is what I see: > > A scope looking at the RF waveform shows NO am modulation. The envelope > is clean. > > A scope looking at the RF waveform does show a slight blurriness in the > horizontal axis indicating rapid but slight frequency shift. > > A scope monitoring the 12 volt input shows a small sinusoid waveform on > the 12 volt input (a hundred mV or so) indicating that there is a > significant AC component of current being drawn from the battery. The > frequency of this AC component of input current is about 30 hertz. > > I suspect ALC instability of some kind. I could sure use some help here. > > Don K7FJ > > _______________________________________________ > 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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