02-10-2019, 11:22 PM
Thanks for all your help Scott! I appreciate all the time you've put into posting suggestions for me ;) And everyone else that has helped me...there have been many. I don't think I'm done yet...my biggest concerns are the little bit of distortion and the fact that I receive 90.9 at about 107 on the dial. And I'm still concerned about the 15k 2W resistor dissipating close to 2 watts. I think it's better now that the IF can has been replaced and FM is working but I'll take another reading tomorrow. I'm also concerned that the output (at the voice coil) rides on top of a sine wave, about 200mV peak-to-peak. Is that normal?
Maybe I'm worrying too much, but I want this thing to work right for a long time.
Ok, to answer your question Scott...I'm pretty sure the 3rd IF (AM detector/FM discriminator) was the primary problem. I can't explain why I didn't get solid FM when I had it tacked into the circuit, but it did allow me to do the FM alignment properly, which I couldn't do before replacing it. Perhaps I had it tacked in improperly but I don't think so. But when I soldered it in permanently I did make a mistake, and once I corrected that it came to life and I'm glad.
Rich
Maybe I'm worrying too much, but I want this thing to work right for a long time.
Ok, to answer your question Scott...I'm pretty sure the 3rd IF (AM detector/FM discriminator) was the primary problem. I can't explain why I didn't get solid FM when I had it tacked into the circuit, but it did allow me to do the FM alignment properly, which I couldn't do before replacing it. Perhaps I had it tacked in improperly but I don't think so. But when I soldered it in permanently I did make a mistake, and once I corrected that it came to life and I'm glad.
Rich