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Philco 70 output transformer
#23

Got back around to this, surprised the unit can be dialed in at all. The 30 AWG wire I used to rewind the oscillator is app. .2 mm diameter vs app. .15 of the original wire. I wired it up to the coil's original center tap hole, then on up the the coil's original top hole to complete the taps. So the original wire is only app. 75% diameter of what I used, then I am app. 75% of the inductance it needs (don't know how linear inductance builds up though, and how diameter affects it yet). I measure .15 mH currently, but need .26 mH to bring the broadcast band's to app. the 260k IF that this unit uses. I thought someone might have put in a different coil at some point and that's why the radio was parked and when I rewired - same problem. The mounting bracket does look newer than the other coil's brackets and has a orange paint dot on it. Could try substituting the 410pf and 110pf as a simpler solution, but don't know if the spread would work out. My .15 inductance bounced against the 410pf = 641.77 khz vs. .26 against 410 pf = 487.46 when pushed against the middle 750rf would be 260khz if. Also, strange to me, since this is my first coil excursion, I measure .25 mH on the coil outside the aluminum case, but inside .15 - I added some turns to the top, but only a few more mH. Playing this radio with the original NC disease coils gave glimpses of AM like I have never heard, tweaking and dialing in in I heard bass and details that were unreal from an AM unit - also some high frequencies that I did not think possible, so I know it's in there somewhere, even though this non AVC unit will vary, esp. at night. I will find it. With this 30 AWG, the 1st RF and osc. coils don't pump out like the 36 or so wire will, but music now sounds like music ungarbled compared against the old corroded coils. Going to try 36 AWG as some have said. It's starting to pop in like it should even though it's on the side of 260 - fun to tweak the IF side best for the current coils, then rock the oscillator and trimmers to get totally different tones and sounds.


Messages In This Thread
Philco 70 output transformer - by radio1 - 05-06-2020, 06:49 PM
RE: Philco 70 output transformer - by Radioroslyn - 05-06-2020, 07:32 PM
RE: Philco 70 output transformer - by radio1 - 05-06-2020, 07:40 PM
RE: Philco 70 output transformer - by klondike98 - 05-06-2020, 09:45 PM
RE: Philco 70 output transformer - by rfeenstra - 05-06-2020, 10:31 PM
RE: Philco 70 output transformer - by klondike98 - 05-06-2020, 10:56 PM
RE: Philco 70 output transformer - by radio1 - 05-07-2020, 04:45 AM
RE: Philco 70 output transformer - by Steve Davis - 05-07-2020, 07:58 AM
RE: Philco 70 output transformer - by radio1 - 05-07-2020, 08:59 AM
RE: Philco 70 output transformer - by radio1 - 05-07-2020, 10:20 AM
RE: Philco 70 output transformer - by morzh - 05-07-2020, 10:40 AM
RE: Philco 70 output transformer - by rfeenstra - 05-07-2020, 11:01 AM
RE: Philco 70 output transformer - by radio1 - 05-07-2020, 11:21 AM
RE: Philco 70 output transformer - by morzh - 05-07-2020, 11:46 AM
RE: Philco 70 output transformer - by rfeenstra - 05-07-2020, 11:56 AM
RE: Philco 70 output transformer - by radio1 - 05-07-2020, 06:34 PM
RE: Philco 70 output transformer - by morzh - 05-07-2020, 07:46 PM
RE: Philco 70 output transformer - by radio1 - 05-08-2020, 03:17 PM
RE: Philco 70 output transformer - by morzh - 05-08-2020, 03:51 PM
RE: Philco 70 output transformer - by radio1 - 05-18-2020, 05:52 PM
RE: Philco 70 output transformer - by radio1 - 05-19-2020, 07:26 PM
RE: Philco 70 output transformer - by radio1 - 05-27-2020, 07:19 PM
RE: Philco 70 output transformer - by radio1 - 06-06-2020, 07:22 PM



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