02-22-2019, 09:06 PM
+ Mike
>I went through all the coils on the Model 91 and found two open primaries in addition to the other problems.
The ant and rf coils are simple to prepare. Peel off old (small winding on the outside) winding, remove celluloid strip, replace w/mylar strip, wind abt 20t of small magnet wire (like 32-38g), replace it back into the set. THe primary is not part of the tuned circuit (that's the large winding) so it's very forgiving. THe feedback winding on the osc coil is a little trickier as it must but phased (wound) is the same direction as the other winding. It's not uncommon to find green dots on the old windings this is where the copper wire has rotted and has created a open circuit.
> I kind of think this radio got too many problems for right now and have put aside.
You know if you keep that up you'll end up like me w/ 50 chassis all a part and remembering what goes to what!
>With respect to the Model 90 which has one 47
That would mid alliteration of the model 90.
<a check of the coils revealed an open primary on the first detector xfmr
I would have a close look at the open coil to see if the wire is broken at the terminal. May just need a little solder.
>I went through all the coils on the Model 91 and found two open primaries in addition to the other problems.
The ant and rf coils are simple to prepare. Peel off old (small winding on the outside) winding, remove celluloid strip, replace w/mylar strip, wind abt 20t of small magnet wire (like 32-38g), replace it back into the set. THe primary is not part of the tuned circuit (that's the large winding) so it's very forgiving. THe feedback winding on the osc coil is a little trickier as it must but phased (wound) is the same direction as the other winding. It's not uncommon to find green dots on the old windings this is where the copper wire has rotted and has created a open circuit.
> I kind of think this radio got too many problems for right now and have put aside.
You know if you keep that up you'll end up like me w/ 50 chassis all a part and remembering what goes to what!
>With respect to the Model 90 which has one 47
That would mid alliteration of the model 90.
<a check of the coils revealed an open primary on the first detector xfmr
I would have a close look at the open coil to see if the wire is broken at the terminal. May just need a little solder.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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