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Philco 70 tuning backward?
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(10-07-2016, 10:34 PM)btoher Wrote:  Hi, I am just getting back to restoring a Philco radio after a long break from them. But i like philcos and always wanted a 70 or a 90. Not feeling too lucky at the moment, but will eventually . It is an earlier serial number 70.Not in the best of shape but I am determined to get it back to normal as possible.The problem is I am stuck and could use some help . Maybe someone has run into this symptom before. 1420 khz station comes in at 1120 on the dial 1190 kHz comes in at 1410. Backwards! I flipped the oscillator feedback coil wires .no change.The silver micas should be .00011 on the oscillator but were .ooo42 . I had a .00025. So  I installed it .No real change.I have done the normal cap and resistor changes - no change.I have checked coils no opens. Not sure if they are rewound but does hot look it.Any ideas much appreciated ! Nothing below 900 on dial .With signal gen only low tone below 900.Is there some thing obvious I should look at? Thanks for any help!
Bill
 
  Good  Morning ,I wanted to add some more detail and ask another related question. The IF coil appears to have had some repair .The primary is 18 ohms and the secondary is 7.8 ohms .The 1st detector coil is primary 17 ohms secondary 4.4 ohms . Not that this is the problem ,but I do not know. I have read and looked for what the coils should read on this model and can not find any approximate values listed .Right now I have the set on a long wire antenna , but am moving it back to the bench and look at it with signal gen and scope . I have a lot of back ground information that I can add . For instance the tuning gang was rebuilt ,cleaned new insulators etc. What is weird is the rotor just sits in the rear of the gang with a wire strap to hold it in place. No bushing or anything . I have had to grease that because dry the hold down wire  was wearing at the shaft . I went through all the spacing of plate checks  I could . Nothing touching . Even with the lack of a good bushing in the back of the gang . The first noticeable thing in the alignment was how strong the 266 khz I.F was . But it was adjustable . Second thing was how weak the lower signal was on alignment , there is no AVC on this model . Last the #4 tuning trimmer and # 7 low frequency adjustment seem to have no effect . So as you can see I am clutching at straws and need to get methodical . Right now I am sort of brain dead as to what to do . Not even 100% sure that the tuning is linear backwards as I think a strong local station comes in way off the mark in a place that makes no sense.I have order the correct .00011 micas for the oscillator .But because all my fiddling around there has not seemed to result in any change I have low confidence that will do the trick . Still my goal is to get this thing back little by little to the print . Thanks for any help . I would really like some normal coil ohms date if it is out there? Thanks !
Bill


Messages In This Thread
Philco 70 tuning backward? - by btoher - 10-07-2016, 10:34 PM
RE: Philco 70 tuning backward? - by morzh - 10-08-2016, 09:29 AM
RE: Philco 70 tuning backward? - by btoher - 10-09-2016, 08:53 PM
RE: Philco 70 tuning backward? - by btoher - 10-08-2016, 10:02 AM
RE: Philco 70 tuning backward? - by morzh - 10-08-2016, 11:24 AM
RE: Philco 70 tuning backward? - by Radioroslyn - 10-08-2016, 11:48 AM
RE: Philco 70 tuning backward? - by sam - 10-08-2016, 12:42 PM
RE: Philco 70 tuning backward? - by btoher - 10-08-2016, 06:46 PM
RE: Philco 70 tuning backward? - by morzh - 10-09-2016, 09:12 PM
RE: Philco 70 tuning backward? - by btoher - 10-09-2016, 11:33 PM
RE: Philco 70 tuning backward? - by Radioroslyn - 10-10-2016, 12:53 AM
RE: Philco 70 tuning backward? - by btoher - 10-14-2016, 09:15 PM
RE: Philco 70 tuning backward? - by btoher - 10-16-2016, 12:24 PM
RE: Philco 70 tuning backward? - by Radioroslyn - 10-16-2016, 03:06 PM
RE: Philco 70 tuning backward? - by btoher - 10-17-2016, 07:34 PM
RE: Philco 70 tuning backward? - by Radioroslyn - 10-17-2016, 07:50 PM
RE: Philco 70 tuning backward? - by Steve Davis - 10-17-2016, 08:25 PM
RE: Philco 70 tuning backward? - by Radioroslyn - 10-17-2016, 09:28 PM
RE: Philco 70 tuning backward? - by btoher - 10-18-2016, 07:38 PM
RE: Philco 70 tuning backward? - by Steve Davis - 10-19-2016, 07:14 PM
RE: Philco 70 tuning backward? - by btoher - 10-23-2016, 04:28 PM



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