The PHILCO Phorum

Nice work. Looking foward to fire up.

(02-22-2015, 05:00 PM)Mike Wrote: [ -> ]Nice work. Looking foward to fire up.

+1  

Oh....yeah, that speaker again
I guess, a Philco 39-7 speaker to the rescue all over again.

Please dont say Fire when Mike is working on one of my helpless radios,

A+ Mike

Oh and I may have cut off a bunch of wire that was hanging off the chassis but I don't think it will affect anything right.

Kirk

Any more confessions?
Did you forget the rule "don't cut off what's hanging, you might regret it!" ?

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Mike 
Looking good 

Looks good Mike but just a thought. In the picture below there seems to me much more wire on the small bobbin. 
Maybe I really did remove wire? 

If you did it is no good. Why didn't you put this photo out before?
Do you have other photos of this coil?
Any other wires removed?


Wll, I will dismantle it and try to count turns on the photo.
For the future, the length of the wire left is the key, so do not touch it.

I don't think I would ever do that but I will look for photos when I get home.
I know I thought about it so I just wanted to say it as a far off maybe.

Hope I didn't screw this up

Kirk

Well...imagine you came to a doctor with a majorpain in your behind. But because you feel uncomfy to tlk about it, the doc did something else, and you left the office with the same pain in your behind but without your tonsills and a prescription for estrogen ingections and a free box of Tic-Tacs.

You give me a pretty chewed up chassis that also has no sch, might as well tell me everything you know, every little bit helps.

OK. Disconnected the coil, wound 30 turns (this is what I was able to count on the photo).

Major pain in the behind? is that a metaphor for me

At least I will have nice boobs doc

Sorry Mike, I cant believe I didn't think of that and I cant believe I cut it... !!

If it doesnt work this time just call it done.
You have done enough work on it...

Kirk

Well,

I suspect if it works, the coil will still need adjstment.

Thing is, the coil in question is a part of the first tuning resonant tank. So the inductance of it is important.

Now, the formula for cylidrical coil involves:

1. Square of the number of turns (so it is the most important) and this is what we are guessing.
2. Length of the winding. This we also do not know.
3. Crossection area of the bobbin. This we know.

So, first order of approximation is, I think, OK, but then it will need some adjustment.

Some radio....

While resoldering electrolytics (wires cracked so I actually just put one right where the wires came from, and other needed a shorter single wire) I could not understand one wire coming to the solder post which came from dial lamps.
Obviously it was connected to the negative (xfmr centertap.)

http://www.nostalgiaair.org/PagesByModel...010931.pdf

But.
This sch shows a sepatate winding for that.
I think they rely on negative bias developed across the field coil and the divider to light th lamps!

Wow....

Well, I rewound the coil, put 33 turns and will try to see (if it comes to life) how the signal resonates.



PS. Kirk, dost thou have the speaker AND canst thou measure thy speaker's field coil resistance?