Re: [Drakelist] Drake R4B 5595 kHz oscillator/mixer
- Original Message - From: Charles Bostian bost...@vt.edu To: drakelist@zerobeat.net Sent: Friday, November 14, 2014 1:58 PM Subject: [Drakelist] Drake R4B 5595 kHz oscillator/mixer I am trying to bring my old R4B/T4XB combination back to life after about 35 years of non-use. The 5595 kHz oscillator part of the second mixer 12BE6 circuit does not oscillate. I have tried several tubes with no effect. As far as I can determine, the tube is functioning normally and I can make the receiver work (after a fashion) by injecting a 5595 kHz signal from an external source. Before I take out/test/replace the handfull of Rs and Cs and also look for a replacement xtal, I am wondering if anyone on the list has had a similar problem. In particular, can you recommend a source for a replacement xtal? Thanks! Charles W4KEP It may well be the crystal. Replacements can be obtained from International Crystal. I've bought many crystals from them and all were perfect. They know the parameters for Drake crystals. You might want to post also to the other drake list at: http://groups.yahoo.com/group/DrakeRadio/ It seems to me this is a fairly common problem. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake R4B 5595 kHz oscillator/mixer
the oscillator may be working but on another frequency. if you have a receiver that you can listen around the 5595 wrap a few turns around the second mixer, hook it up to the receiver and tune around the frequency. you may have a cap or inductor that has changed value and the oscillator is still working. if the oscillator is working you can add or subtract capacitance or inductance to bring it to the correct frequency. i have done this many times and it works. mickey wa6fiz On Nov 15, 2014, at 8:50 AM, Richard Knoppow 1oldle...@ix.netcom.com wrote: - Original Message - From: Charles Bostian bost...@vt.edu To: drakelist@zerobeat.net Sent: Friday, November 14, 2014 1:58 PM Subject: [Drakelist] Drake R4B 5595 kHz oscillator/mixer I am trying to bring my old R4B/T4XB combination back to life after about 35 years of non-use. The 5595 kHz oscillator part of the second mixer 12BE6 circuit does not oscillate. I have tried several tubes with no effect. As far as I can determine, the tube is functioning normally and I can make the receiver work (after a fashion) by injecting a 5595 kHz signal from an external source. Before I take out/test/replace the handful of Rs and Cs and also look for a replacement xtal, I am wondering if anyone on the list has had a similar problem. In particular, can you recommend a source for a replacement xtal? Thanks! Charles W4KEP It may well be the crystal. Replacements can be obtained from International Crystal. I've bought many crystals from them and all were perfect. They know the parameters for Drake crystals. You might want to post also to the other drake list at: http://groups.yahoo.com/group/DrakeRadio/ It seems to me this is a fairly common problem. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Drake R4B 5595 kHz oscillator/mixer
My thanks to everyone who has sent me ideas. At one of your suggestions I built a simple circuit to check the xtal performance. It works fine - series resonant at 5563.3 kHz and parallel resonant between 5599.1 and 5599.3 kHz. So the problem must be in the four caps I haven't checked yet. Naturally they are the four hardest parts to get to! Charles W4KEP -- Charles W. Bostian Alumni Distinguished Professor of ECE Emeritus Virginia Tech 1609 Kennedy Avenue Blacksburg, VA 24060-5731 540-552-9327 (H) ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake R4B 5595 kHz oscillator/mixer
It could very well be a bad crystal. If you or a friend have a crystal not too far from that frequency, you can wire it in and just see if the circuit oscillates. Dennis AE6C On Sat, Nov 15, 2014 at 12:09 PM, Morrell Siegel mandbsie...@charter.net wrote: the oscillator may be working but on another frequency. if you have a receiver that you can listen around the 5595 wrap a few turns around the second mixer, hook it up to the receiver and tune around the frequency. you may have a cap or inductor that has changed value and the oscillator is still working. if the oscillator is working you can add or subtract capacitance or inductance to bring it to the correct frequency. i have done this many times and it works. mickey wa6fiz On Nov 15, 2014, at 8:50 AM, Richard Knoppow 1oldle...@ix.netcom.com wrote: - Original Message - From: Charles Bostian bost...@vt.edu To: drakelist@zerobeat.net Sent: Friday, November 14, 2014 1:58 PM Subject: [Drakelist] Drake R4B 5595 kHz oscillator/mixer I am trying to bring my old R4B/T4XB combination back to life after about 35 years of non-use. The 5595 kHz oscillator part of the second mixer 12BE6 circuit does not oscillate. I have tried several tubes with no effect. As far as I can determine, the tube is functioning normally and I can make the receiver work (after a fashion) by injecting a 5595 kHz signal from an external source. Before I take out/test/replace the handful of Rs and Cs and also look for a replacement xtal, I am wondering if anyone on the list has had a similar problem. In particular, can you recommend a source for a replacement xtal? Thanks! Charles W4KEP It may well be the crystal. Replacements can be obtained from International Crystal. I've bought many crystals from them and all were perfect. They know the parameters for Drake crystals. You might want to post also to the other drake list at: http://groups.yahoo.com/group/DrakeRadio/ It seems to me this is a fairly common problem. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
