[EMAIL PROTECTED] writes: > I still suspect a phasing problem, perhaps a double error.
I know what you mean, but I did use a dual-trace scope to confirm that the grids of the push-pull 1st audio stage are getting signals that are 180 deg out of phase from each other. I will do the same on the grids of the 833s later today to make sure that is carried through to them. The entire low-level audio section, from 1st audio to the grids of the 833s, has been replaced with another pc board, this one with 807s instead of the sweep tubes. The low-modulation condition was the same with the earlier board in place as on the 807 version. While the designers were a bit silly to use printed circuitry in this rig, I do admit that the pc board helps ensure that no wires are swapped within the stages. Every component on the 807 audio board is brand new and checked. >Another thought is to temporarily disable one half of the push-pull >circuitry, perhaps by removing tubes. If you get more output from one-half >the circuit, it would verify a phasing problem. Good idea - I'll give that a try. >Wonder also if you have a large power resistor (200 w) of 2500-5000 ohms I wish I did, but so far I've not found anything high enough that could serve. Drives me nuts to think of the multitudes of suitable resistors I've had broadcast sites in my past positions - no access now. The big resistor I have is 50 ohm as shown in the photo at http://www.wd8das.net/BigR.jpg -grin- Steve WD8DAS ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net 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.
