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Thanks to all who helped in reconstruction of this radio, coming to the home stretch, there is a loud squeal when volume is mid range have not done a good alignment and this may address this but not sure. any suggestions? can get some stations on a really bad antenna set up, also rather garbled when on station. Ron helped with dirty pin connection on 14af7.
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Do not know this radio, but if it has tube shields, are all of them in place and are all grid wires that should be inside the shields are indeed inside?
Just a thought.
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No tube shields but good thought. Thanks
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Well, you should do the alignment first. And sometimes you have to back off a hair from "perfect" on first or second IF to cure squeals, don't know why, but have been there. Also check/clean volume potentiometer. Been there too.
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Thanks, that was my plan so will give it a try this eve and let You know how I fair. This forum is a great place to pick everyone's brain and the info is, as always, welcome. Being a newbie, all the input has been a great help. I felt as if I may have tackled a project that was way beyond my pay grade but all the info I received has been fantastic and appreciated.
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I second that about notching it back just shy of perfect with IF, found that out with Atwater Kent, though never saw it on PHILCOs.
Although I have yet to understand how this would result in howling when the volume is increased (with IF it is oscilation through feedback due to superhigh gain).
Also see if the volume wires are routed funny....missing wire shields (if any - have that on the Packard Bell)....and, last but not least, tubes do that too at times.
(This post was last modified: 02-03-2015, 11:47 AM by
morzh.)
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Will give that a try also if the alignment does not cure the problem. Volume control had a bad spot in it bur wd 40 seemed to correct it, time will tell.
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Some Philcos of this vintage are made to use their specific loop antennas and will squeal if you use a random wire like many of us use as test bench antennas. Others seem to work OK on a random wire.
You should for sure use the correct loop antenna installed in the cabinet and connected to the chassis with original short leads (or only short extenders) to do any final alignment. If you can reach the compensators with the chassis installed in the cabinet, that would be best, but I've had good luck putting the chassis on a table back-to-back to the chassis (antenna installed in cabinet) so that the original wires will reach. Electrically, that's almost equivalent to having everything installed in the cabinet as designed.
John Honeycutt