Philco 46-420 Code 121 Reception issues - Printable Version
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Philco 46-420 Code 121 Reception issues - Eric - 10-29-2024
Friends I'm having an issue with a Philco 46-420 (Hippo model) Code 121.
http://www.nostalgiaair.org/Resources/597/M0013597.htm
Tubes 7c7, 7a8, 7b7, 7c6, 50L6, 35z5.
It plays I do pick up the two major stations 750 & 680 in the ATL area but I get a lot of static much more than you would expect from a 6 tube radio. Volume works fine. I even took it outside to see if it made a difference and it didn't. Checked for in house issues like dimmers all was good
What I have done.
All tubes tested good and I even substituted spares I had and it made no difference
It was restored filter caps and paper caps. Some were done by previous owner. Only the PF mica caps remain.
I did an alignment no problems in getting a tone and peaking the IF's
One thing I noticed C404A the bottom segment of the tuner section where one lead of the loop antenna attaches that you peak at 1500KC made no difference when you adjusted it. The problem?
Bad Mica cap I know it is rare but does happen.
I checked resistance of the IF's and they were fine also no problem peaking
Antenna coil resistance is good per print
I used the Philco Service manual and went through the sections and all check's and had tone where I was supposed too.
Not sure what to check next any ideas
Eric
RE: Philco 46-420 Code 121 Reception issues - klondike98 - 11-24-2024
You mentioned the Philco manual and going through the check points...just to be sure we're on the same page here's the manual from our library: https://philcoradio.com/library/download/service%20info/yearbooks/1946-1947/split/Part11-Philco%20Home%20Radio%20Yearbook%201946-1947.pdf
I'm assuming you changed the dual electrolytic caps as well as all the paper ones, probably would not work at all if you had not. Static can be hard to track down, at least for me. No one else has chimed in so I don't think there are many more things to try. One thing I've seen is dirty tuning cap and/or dirty volume control can cause static. Try it in different positions around your house as well. Maybe there is a quieter spot.
If you tap the IF cans z300 and z301 and the static changes a lot or it sounds microphonic then the caps in the IF can may be faulty. I don't know if SMD silver mica disease) is a problem in these sets or not. I have a 1949 set that suffers from it and is causes popping and high and low volume at random times but is very bad when the IF can is tapped on. Just a few thoughts.
RE: Philco 46-420 Code 121 Reception issues - radiorich - 11-24-2024
Welcome Eric,
I agree with Bob and far as the two main electrolytic filter capacitors did you change them yourself or were they changed in the past ?
Sincerely Richard