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Philco Shadowgraph meter, the old style, coil removal
#17

Well, it has just come back.
The resistance is 1.1K, don't know how many turns but supposedly they went by repair manuals, and I also pointed them to that article at Philcorepairbench. They at some point mentioned #41 wire and not #40, I will have to ask them what wire they ended up using.

I took a guess about the polarity as they used two white wires to make the leads. I guessed it right as the shadow seems to narrow when I tune in.

Not everything is working like it should, and I have to check a few things.

One is, if they used #41 wire and not #40 then it takes less turns to achieve 1.1K, but what really matters is that number of turns as this is what creates the field, so with less turns it may be weaker.
Then again, I think the current icreases when it is "Off-tune" so the stronger current widens the shadow, not narrows it, so I may be OK and it is the Off-tune width that would suffer. And it is acceptable.

When the radio starts though, the shadow goes to the most narrow. Don't know whether that is an indicator or not.

I guiess I will have to re-read the procedure at Philcorepairbench.

I will have to ask experts in the Philco documentaion a couple of questions in my Philco 18 thread.


Messages In This Thread
RE: Philco Shadowgraph meter, the old style, coil removal - by morzh - 03-29-2013, 10:31 PM



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