Is the oscillator freq on the low end too high and needs to be lower or is it to low and needs to be higher.
Some one mentioned that the oscillator may be running on the wrong side. You may know this already but I will state it anyway, that the OSC must be running above the RF that you want to receive. OSC = RF + IF. It is some times possible to pull the OSC with the trimmer all the way down to where the OSC = RF - IF. This will work where you set it but it will not track as the manufacture did not design it that way. Assuming that the culprit is ageing coil forms, not incorrect parts or IF misalignment, there could be a number of quick fixes for this type of thing. Padding capacitors can be added in series with the top end of the coils or extra turns could be added to the coil assembly or just placed in series with it. I have beat up some powdered iron and put it into the coil form with glue to lower the frequency. John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Van K7VS Sent: Tuesday, September 25, 2007 11:04 PM To: Discussion of AM Radio in the Amateur Service Subject: [AMRadio] NC-183D Alignment questions help I have a pristine NC-183D I picked up a year ago that I am finally getting around to. Have replaced all the electrolytics and sound really good. BUT...I cannot get it to track properly as I follow the alignment instructions in the manual. I can set the top frequency on each band with a small trimmer cap (this is the oscillator coil adjustment) but then according to the instruction manual you adjust the low end of the dial by moving a wire inside an inductor, which does move the lower frequency but not nearly enough to get to the frequency they say you should see. Has anyone else had that problem during alignment of this receiver, or am I missing something. Have checked the voltages at the first and second converter and they seem fine and have pulled off the mica cap across one of the oscillator coils (1.8 to 5 Mhz) and it checked just fine (supposed to be 1600 pf and reads 1615 pf). And have substituted a different 6BE6 in the first converter and still can't get close to proper or accurate dial tracking. I am 500+ Khz off no matter what I have tried. And thoughts on this one! Thanks. Van, K7VS PS I would like to hear from NC-183D owners that may have experienced this problem or have some thoughts about what I am seeing. tnx ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
