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Working on Philco 46-421. Recapped, all resistors out of spec were replaced. Radio picks up all local stations but has low volume. I checked the volume control and am reading about 1 mill. Schematic calls for 500,000. Will this cause the low volume??
Thanks,
Joe
http://www.nostalgiaair.org/resources/599/M0013599.htm
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Thanks for including a schematic link.
No, as long as the wiper of the pot is making good contact. Can verify with an ohmmeter.
Make basic voltage checks on the tube pins as given on the schematic to see if any are far out of range.
Check the antenna connections too.
Ultimately an alignment may be called for.
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You do not state in your post whether you have done a full alignment on the set yet or tested the tubes. These should be done.
Poor alignment and/or a weak tube(s) can cause this.
If volume is still low, then we can look for other causes.
Chuck
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All voltage readings taken-they seem a little high- but within reason.
Tubes will be checked next time out for a weak one.
Aligned it as best I could- signal generator acting up- another project. I put the strongest channel we have on and adjusted the IFs to max.
On the original work there were several resistors that increased the volume a little when replaced.
Will continue the work at next chance.
Thanks,
Joe
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Spend the dollar or so to replace the rest of the ancient resistors. You can get a good enough digital frequency meter for very little nowadays. Old signal generators can get quite cranky. Mine was off by more than 10 KZ before I checked.
Best of luck.
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Codefox,
Any name brand or the like I should look for? What is very little these days?
Thanks,
Joe
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If you mainly aim at tuning old AM radios, a heathkit or Eico can usually be had for very little fro whaterver local ham festival or even EvilBay. Of course you have to treat it as an old radio and recap, check resistors, etc... The other accessory is a frequency counter, and a modern digital one can be had cheaply (less than $30) from same source or wherever.
Many were built from kits, so quality varies. If it is an old one you will have to be patient.
Between the two, and leave #1 on an hour or so, you can get very accurate, or good enough standards to align radios. Note bene all these signal generators will put out significant harmonics (actually that's how they work!) so you can be led down the garden path if a golden screwdriver has been in your set before.
You can get a good enough frequency counter surplus or new digital meter with frequency determination or whatever for less than $35 if you scrounge around. It's not a heartbreak if you bust one of these out, just a mild kick in the you know where.
I recently found a radio that was tuned to 1/2 IF, and still worked a little, but once I got it back to where it should be, it's a champ. Not many of newer ones would tune as low.
Anyway there are a number of ways of doing away with signal generator by using a not screwed up radio next to your set, well covered here and on net.
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Low and behold -- a very weak 7C6 tube. Feel silly I missed this the first time I checked. Have to track one down as none in stock.
Redid all resistors in radio.
Also recapped and resistored my Eico 324 and Accurate tube tester.
Should make life a little easier.
Will keep you posted when tube is tracked down.
Thanks,
Joe