Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA
I have a 49-505 and I can't seem catch a break with SMD the thunderstorm that never ends! Here is the link.
http://www.nostalgiaair.org/pagesbymodel...013664.pdf
The output IF #36 has 6 solder points ( As opposed to 4 if the Input IF) and shows to caps (100pf each) tapped in the center to the B-. What do these do?
Also on the Input IF I opened up the existing caps and put in 100pf caps on each side. I can find no value for these but from a previous post someone said that these values should work. Thoughts?
Thanks Eric
Posts: 24
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Joined: Jan 2020
City: Laceys Spring
State, Province, Country: Alabama
Hello, the two extra 100pf capacitors on the IF can with the six terminals act as some kind of rf filter. You can replace those when you replace the other two mica caps in the can. I have rebuilt this rf filter outside the can, very easy. Also, sometimes 100pf caps won't work in all situations. I recently restored a Philco 53-564 and had to replace all the mica caps in the if transformers. When I used 100pf caps on the transformer with the six terminals, I couldn't get the transformer to peak out correctly and ended up turning the slug all the way in one direction to get any reception at all. This is what I did....I very lightly tacked in 110pf caps and retried to see how they would work , then 120pf, then 130pf. Just tried each one until I settled in on 120pf. You just have to experiment with different values until you find the value that works best. Just lightly tack the caps in while you test, so you can remove them easily to try a different value. Once you find the best value, you can shorten the leads and solder them in better. My 53-564 works great now. You can also do it a different way using mica trimmer capacitors. Go to YouTube and look for Shango066 and watch his video on SMD repair using mica trimmer capacitors. He's very knowledgeable on this subject.
Posts: 451
Threads: 85
Joined: Nov 2011
City: Cumming, GA