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I have a Philco 42-327 Rider 14-31
http://www.nostalgiaair.org/PagesByModel...013515.pdf
Changed the caps and replaced a couple of missing tubes and powered up the radio and got static no smoke so far so good. It works on the sw as I have gotten some foreign broadcast at the high end of the scale. On BC I get static, set the signal gen to 455 and got tone at 480 with the gang fully closed should I be able to adjust this down using 24 A&B because it doesn't seem to move the signal just fade it in and out?
Eric
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Did you try moving the generator down a bit then repeaking the trimmers on both IF's?
Terry
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Yes I did, the tone will fade as I turn the screw (24B) but when I turn the dial on the signal gen it doesn't follow. 24A doesn't seem do anything?
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Do you have plate voltage on both plates of the mixer tube?? Where are you injecting the IF signal??
Terry
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These sets are a bit weird, they don't use a conventional convertor tube they use a dual triode mixer oscillator tube called an XXD/14AF7, they also have an extra IF amplifier stage. A stupid question but is the band switch set on dial tuning instead of pushbutton tuning? There are three IF transformers, the first has two trimmers but the second and third ones have one trimmer each marked 29A and 35A respectively, the 455 kc signal should go into the antenna section of the tuning capacitor.
Regards
Arran
(This post was last modified: 02-07-2013, 10:59 PM by
Arran.)
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It is entirely possible that the oscillator for the broadcast band isn't functioning for some reason, a bad resistor, a bad mica cap, or even an open oscillator coil could cause this. I would start checking voltages on the XXD tube, particularly the oscillator section.
Regards
Arran
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Hi Eric,
Check the tube pins and make sure they are clean. Loktals are know to sometimes have a little corrosion in them, causing bad contact. Something simple to check.
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Agree you need to realign the IF and check all the things mentioned. I once had a 42-327 that had the same symptoms as yours and mine turned out to be the local oscillator was not working on BCB but was fine on SW. Bad mica cap.
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Got a lot of things to check now. Thanks to all I will post when I know more
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Ok, when I started to see what the voltages were on the XXD and put the meter lead on pin 4 the radio started playing and you could tune in stations I followed it back to the OSC lead #6 is this an indication of an open winding?
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This morning started looking at the OSC and the mica caps especially at point 6 on the OSC first checked #9 and it came in at 260pf. Then # 5on the print calls for 5pf but the dots on the cap say it should be 100 pf but reads 19pf so I put in a 10 and nothing then put in a 100 and the radio plays fine. Thanks for the help now to clean the chassis and the cabinet. Love this site!
Eric
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Me too, was on my Philco. SSDD. Glad you gort it working.
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Congrats, Eric. I can't recall which was my bad cap...I'm thinking it was #9. What I remember most is that it was the most buried one in that part of the circuit!
