Philco 41-300 output transformer question. - Printable Version

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RE: Philco 41-300 output transformer question. - Tomie - 10-23-2017

I got a used output transformer that was out of an older radio with 6v6 push pull output. I don't know what radio it came out of so unfortunately I don't have a print or good independent specifications. I did note for my purposes that the primary winding DC resistance was around 360 ohms compared to the Zenith output transformer and speaker I have been using to test at around 580 ohms primary DC resistance. The original Philco transformer was 640 ohms. Both the original and replacement transformers are wound 48 to 1.
The radio sounds good now, but not exceptional. I am using the original Philco speaker and it's not bad. I agree with Morzh, it doesn't sound as nice as I anticipated it would sound, but it is now acceptable.
I'm not ready to put the chassis back into the cabinet as I have other cabinet issues I need to address first. But I did install one of the two speakers back into the cabinet and then slipped the receiver in just to hear it. Of course there is additional improvement once the speaker is in the cabinet.
The one recommendation I would make for whomever replaces an output transformer on one of these receivers in the future, I think it is worth your while, no matter what formula you use to select a replacement transformer, to make as certain as you can that the transformer has good low end frequency response in order to get the best performance from this receiver.
I am now ready to align at least a couple of the push buttons. The Philco literature says I need a Philco loktal aligning adapter part number 45-2767. It appears that there is one wire coming from the loktal adapter so it appears to basically act as a tap to some point on the 7C6 AF tube. Does anyone have information about that part? I'd like to know what pin on the 7C6 it is hooking up to.
Then, the literature continues and tells me I need a model 077 station setter.
Have no idea what that is but I would love to know.
Also, if anybody has aligned those buttons before and has an easy work around to do it I would like to know.
If I need to start a new thread for the push button questions, let me know and I'll repost.
Thanks everyone, have a great day.

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RE: Philco 41-300 output transformer question. - Radioroslyn - 10-23-2017

Hey Tommie,
Setting the buttons are easy. Set band switch to pushbutton. Look into the back of the pb assbly and you'll see two rows of adjusts (trimmer caps). One peaks up the ant the other adj the osc (set what station you'll hear). You'll notice some frequencies stamped into bracket holding the trimmers. It's is the range that the pb associated with the trimmer will tune. Trimmers toward the right side tune the low end of the band the left side the high end. There is a drawing of them of the lower right corner of the schematic.

Push in the second button (1st is the off/on sw) and you should be able set the osc trimmer to hear stations at the low end of the band. You may have to peak up the ant trimmer when adjusting the osc. The next pair of trimmers are for the next button and so on..

Probably a good idea to have the chassis in the cabinet and the loop ant connected.

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