The nice thing about the 50pF capacitors is that there will be less of a dependence on changes in stray capacitance (say from changing tubes in the IF stages) than there would be with 39pF.
The AM IF cans probably use something between 120 and 150 pf./mmf across the primaries and secondaries, if both cans are the same. I remember trying to use values that were too low, like 100 pf, and had the same problem with having to crank the cores all the way in to get it to peak. I tried measuring the micas first and got 142 pf, but I didn't trust my measurement, and didn't have one that size, so I tried the 100s, I ended up stacking a 90 and a 40 pf in parallel.
Thank you! I know its just a cheap radio but you proved all the theory! I was screaming yes turn that lug more! I too am an old TV Radio repair man. I am now unemployed and feeling the pain of it all. Thanks for keeping me sane and rejuviniting me to feel good about myself remembering the skills that I have! Oh to work again using electronics! Question, Shango066 what do you do for a living?
Great to actually see the peaks & s-curve changes, while signal is injected. It plays super clear. Ok, Will go back & review this from the top. As the camera was on the scope, & being the FM IF, the signal (w/the marker) being injected (to get the pattern) is 10.7 Mhz? (from the B&K device), applied to the grids of each stage?
Could you explain how you superimpose the marker onto the sweep signal. I am using a sweep gen from 10.5-10.9mhz swept at 400 hz but can't see my reference 10.7 peak on the scope trace! Help!
Very informative & you've inspired me to one day play with my white plastic GE hybrid clock radio.
Great series on alignment and adjustment on sensitive components. Thanks again Shango!!!!
Prob the best that radio has ever worked after looking at the cheap crap GE used to build it. Thanks bud. Great video!!!!
What a cool series! Thank you so much. This is exactly the kind of thing I want to learn.
Really enjoyed watching the alignment bit, what a balancing act!!
The nice thing about the 50pF capacitors is that there will be less of a dependence on changes in stray capacitance (say from changing tubes in the IF stages) than there would be with 39pF.
Great work with this one, I have learnt alot !
The AM IF cans probably use something between 120 and 150 pf./mmf across the primaries and secondaries, if both cans are the same. I remember trying to use values that were too low, like 100 pf, and had the same problem with having to crank the cores all the way in to get it to peak. I tried measuring the micas first and got 142 pf, but I didn't trust my measurement, and didn't have one that size, so I tried the 100s, I ended up stacking a 90 and a 40 pf in parallel.
Thank you! I know its just a cheap radio but you proved all the theory! I was screaming yes turn that lug more! I too am an old TV Radio repair man. I am now unemployed and feeling the pain of it all. Thanks for keeping me sane and rejuviniting me to feel good about myself remembering the skills that I have! Oh to work again using electronics! Question, Shango066 what do you do for a living?
That was a interesting project. Good stuff. Thanks.
Sounds Great! Good Job
Great to actually see the peaks & s-curve changes, while signal is injected. It plays super clear. Ok, Will go back & review this from the top. As the camera was on the scope, & being the FM IF, the signal (w/the marker) being injected (to get the pattern) is 10.7 Mhz? (from the B&K device), applied to the grids of each stage?
What he switches that we see these the peaks & s-curve changes?
Repair your oscilloscope. He has a big pulsation on nutrition. Most likely +55 volts. Electrolytic capacitors are drying out
Nice job, Shango! ;)
Amazing .. just I wanted to see …
Could you explain how you superimpose the marker onto the sweep signal. I am using a sweep gen from 10.5-10.9mhz swept at 400 hz but can't see my reference 10.7 peak on the scope trace! Help!
interesting vid , small rancher of humans
What equipment is used to do the sweep?
Why not just measure your coil inductance and calculate your caps? Much easier than what you went through.
Why does the marker look so ragged?
use two 22s for the 44
pico? don't you mean micro?
The more GE electronics i see the less impressed I am, just really weird and cheap construction.
21!