Philco 48-1264 Resistor R100 missing ? - Printable Version

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+--- Thread: Philco 48-1264 Resistor R100 missing ? (/showthread.php?tid=21582)

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RE: Philco 48-1264 Resistor R100 missing ? - ascion90 - 10-26-2020

Hi Terry,

during the weekend I reviewed the project and thanks to your suggestions. 

I started from pin 4 and discovered that there was no HV. There was a bad connection from the field coil. I already fixed this section at the beginning of the project, but when I changed the field coil I did a bad connection.

The value of the HV after the 1000 ohms R314 resistor is now 275V instead of 240V. 

After this step everything was almost ok on the section  except for the high value of the voltage. I came back to verify the Pin 2 of the 7R7 and due to the open coil on Z302 there was no Voltage . 

At this point just to verify if something is working on the radio I used a 20 ohm resistor to create continuity instead of the open coil that I think is on the AM part . In this way I have now the HV (275V) on pin 2 of 7R7 .Blue wire from Z302

I switched on the radio and of course no signal on AM band , but without alignment I receive some stations on the FM band with good volume.

I have to look now the 275V instead of the 245V and probably can be the Field coil I used ( 500 ohms instead of 650 ) .

But the real problem is how to rebuild the coil in the Z302 IF Transformer. I am looking for a spare 32-4147 but I didn't find yet. Any suggestion where I can find it?

Thank you so much Terry and sorry for some wrong informations I provided in the other reply.

Camillo

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RE: Philco 48-1264 Resistor R100 missing ? - Radioroslyn - 10-27-2020

Sets that use the 9.1mc IF for the FM band are not very common. 10.7mc was adopted early on and it became the standard. With your situation you could if you have the space near Z-302 to wire in a common 455kc replacement transformer. It doesn't necessarily have to be bolted in, lead length is some what important, and neatness is good. If I were doing it I would look for an IF transformer that has trimmer adjustments at the top as having slugs at the top and bottom may present an alignment problem after mounting. Drill a hole thru the chassis on center with the base of the replacement trans about 5/16" in dia for the wires to connect under the chassis. To mount the trans double side tape or zip tie is ok.

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