When I was younger, I did it the wrong way. I would tune a station, and turn all the IF's and the trimmer on the tuning capacitor to get the loudest sound, lol . I don't have the proper equipment anyway. Thanks for another informative video. Love it!
I wish you had shown the connections between the 415 and your Scope. Did you need to Did you use the Horiz Input on your scope? This video beats the heck out of anything on TV! Thanks for taking your time to show us this.
I don't have the 415 nor the probes. What I do have: a 150Mhz signal gen, scope and 11Mhz function gen(can do sweep). Kindly let me know if these can be used for aligning the FM radio. It's a cheap brand AM/FM transistor radio that I just want to practice your procedure on. thanks again.
Could set function generator to sweep 200 plus KHz with 10.7 MHz center. You have to figure out how to couple into the IF. Maybe a loop like he did it here. You'll have to send ramp from function generator to scope horizontal. You'll connect vertical to the discriminator output. You won't have a marker unless you use the other signal generator and I'm not sure how you'd calibrate that marker without a frequency counter unless your function generator is spot on then you could beat the two together. I'm an amateur enthusiast so you'll have to use my information here to the best of your abilities and see if it can work for you. Good luck!
It seems to me you made it worse. You had about double the sensitivity at the beginning than what you ended up with. I suggest the IF strip had a better resonance at a slightly higher frequency. The important thing is not the marker, it is the best (highest) response, and to get the S curve to cut the zero axis at the same X co-ordinate as the IF peak. You exhibited poor technique by using a metal adjuster, and by fiddling around with the IF cans in an arbitrary sequence instead of right to left across the schematic.
Here I am awhile later. Watching today I considered that it could require stagger tuned IF stages. So peaking the response alone wouldn't necessarily be optimal, but might reduce IF bandwidth. I'm not really sure how this radio actually sets up in terms of IF bandwidth. I would say if it performs well and gets all of the normal FM stations and sounds clear and undistorted then it's right. Also I think that alignment tool is probably aluminum and should have minimal effect on trimmer adjustment screw that is probably at the ground plane. Just my thoughts here. Thanks
Why you want to make an adjustment on the IF ? if they aren't touched before, this is not necessary even if the caps have been changed. If you put the exact caps with the same Microfarad and voltage, no need to be adjusted..
Adjust when sound is distorted or selectivity is poor. I've found many radios and stereos that are out of adjustment. Especially descriminators may need slight adjustment. I have also had radios and stereos that perform flawlessly over five decades old. You know it when you hear it and tune up and down the dial.
When I was younger, I did it the wrong way. I would tune a station, and turn all the IF's and the trimmer on the tuning capacitor to get the loudest sound, lol .
I don't have the proper equipment anyway. Thanks for another informative video. Love it!
I did the same thing to a 6 band radio .
That pretty much works fine on AM. No on FM...
It might be a cheap radio but the information is worth a great deal! Great video!
I say do whatever WORKS & you DID that, Lol! GREAT JOB on this one, Shango!
Thank you for this wonderful guidance video. You didn't say the frequency of your sweep generator!
Thanks for the video, how well you connected the oscilloscope.
I had a radio once that had the tuning knob in the middle. It was an AM radio made by Realtone. I was only 8.
I wish you had shown the connections between the 415 and your Scope. Did you need to Did you use the Horiz Input on your scope?
This video beats the heck out of anything on TV! Thanks for taking your time to show us this.
Where does the scope probe connection go to? I'm not clear about how the whole setup is connected so that the marker shows on the scope WF. thx.
Great info, thanks for sharing!
When you tuned the fm If where did you connect to when you measured the bandpass, was it the i/p to the discriminator?
I don't have the 415 nor the probes. What I do have: a 150Mhz signal gen, scope and 11Mhz function gen(can do sweep). Kindly let me know if these can be used for aligning the FM radio. It's a cheap brand AM/FM transistor radio that I just want to practice your procedure on. thanks again.
Could set function generator to sweep 200 plus KHz with 10.7 MHz center. You have to figure out how to couple into the IF. Maybe a loop like he did it here. You'll have to send ramp from function generator to scope horizontal. You'll connect vertical to the discriminator output. You won't have a marker unless you use the other signal generator and I'm not sure how you'd calibrate that marker without a frequency counter unless your function generator is spot on then you could beat the two together.
I'm an amateur enthusiast so you'll have to use my information here to the best of your abilities and see if it can work for you. Good luck!
Recap for sure
I have the exact same radio at home. There is no sound on either band what should I do?
+Hugh Spearns Fix it? Start from the speaker and work your way back.
Hugh Spearns completely dead? or some hiss?
It seems to me you made it worse. You had about double the sensitivity at the beginning than what you ended up with. I suggest the IF strip had a better resonance at a slightly higher frequency. The important thing is not the marker, it is the best (highest) response, and to get the S curve to cut the zero axis at the same X co-ordinate as the IF peak. You exhibited poor technique by using a metal adjuster, and by fiddling around with the IF cans in an arbitrary sequence instead of right to left across the schematic.
Here I am awhile later. Watching today I considered that it could require stagger tuned IF stages. So peaking the response alone wouldn't necessarily be optimal, but might reduce IF bandwidth. I'm not really sure how this radio actually sets up in terms of IF bandwidth.
I would say if it performs well and gets all of the normal FM stations and sounds clear and undistorted then it's right.
Also I think that alignment tool is probably aluminum and should have minimal effect on trimmer adjustment screw that is probably at the ground plane. Just my thoughts here. Thanks
Why you want to make an adjustment on the IF ? if they aren't touched before, this is not necessary even if the caps have been changed. If you put the exact caps with the same Microfarad and voltage, no need to be adjusted..
is an informative video. i didn't see your video on how to adjust the FM IF's.
Adjust when sound is distorted or selectivity is poor. I've found many radios and stereos that are out of adjustment. Especially descriminators may need slight adjustment. I have also had radios and stereos that perform flawlessly over five decades old. You know it when you hear it and tune up and down the dial.
Using metal screwdrivers for adjusting IF cans? What are you, nuts?