Posts: 6
Threads: 4
Joined: Apr 2014
City: Independence, MO
Hello All;
I have two questions as follows:
I have a Philco 41-265 that I recently purchased that is missing the speaker, speaker mounting board, and the antenna.
1. Does anyone know what the original equipment speaker size and impedance was for the 41-265?
2. Also it appears this model used a heavy gauge wire loop antenna perhaps similar to one used on the Philco 41-280. If so, using the 41-280 antenna as a model, can a similar usable antenna be fabricated from 12 or 14 gauge copper wire?
Thanks in advance for any information that you can give me.
Marion
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Well, you'll need an electromagnetic speaker that will fit in the cabinet after you make a new mounting board, you should be able to estimate original size by front of cabinet. Electrically, the field coil is listed at 1700 ohms, and the output transformer (I assume it is also missing) would match the tube (about 10,000 ohms impedence) to the replacement speaker voice coil impedence (most likely less than 8 ohms.) Of course you can substitue a small choke (or resistor combined with slight (15% or so) increase of filter capacitor values since you will be replacing them anyway before firing the set up) for the field coil and use a more modern permanent magnet speaker if you can't scrounge up something more original. Impedence matching is not all that critical, about the worst you could do is have diminished volume.
Yes, you can make an antenna loop (just scrounge a scrap length of electrical outlet wire, (OK to leave insulation on and/or solder scraps for needed lengtkh, and follow the dust stains in the cabinet to learn how many turns it had, and (not certain if a turn or two is missing or over counts,) make you a new one.
As you will find out, this is not an exact science unless you are working on a museum piece or national treasure. Best!
Schematic here:
http://www.nostalgiaair.org/Resources/413/M0013413.htm
(This post was last modified: 12-24-2014, 12:01 PM by
codefox1.
Edit Reason: add to
)
Posts: 6
Threads: 4
Joined: Apr 2014
City: Independence, MO
Hi Codefox1;
Thanks for the reply and info.
The mounting board should pretty easy. Think I will use a PM speaker with a power resistor to replace the field coil. The output transformer is mounted under the chassis and ohms out good. I will take your advice and increase the size of the filter e-caps to reduce hum.
I will try to make a loop antenna from 12 ga. solid copper wire that I have. I will pattern it after the loop antenna which rotates a few degrees that is in my Philco 41-280.
Thanks again.
Marion