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Yoke Question
Years ago, I obtained an old Emerson projection set from a collector that was about to junk it because the yoke was "burned up". I hauled the thing home, inspected the charred turns on the yoke, and stashed it away in a dark corner of my garage.
Today, I inspected the Norelco "Protelgram" projector again. The outer coil of the yoke for sure has some bare wire and charred looking windings, the focus coil appears to be just fine...Picture 1 But wait a second! ... that is an axial coil, not what one would expect for a deflection yoke. I removed the coil and found some fairly "normal" looking deflection windings... Picture 2 So what is the outer coil? it is connected ONLY with one wire to ground... is it just a shield? Even stranger, BOTH ends of the coil appear to be connected to the ground lug, so it would appear that it is a SHORTED, GROUNDED coil ! ...Picture 3 Anybody know what the purpose of this coil would be... some sort of "magnetic shunt" or what? jr Last edited by jr_tech; 06-09-2017 at 06:26 PM. |
#2
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Ion trap? I've got a GE technical whitepaper describing an Ion Trap Coil - I presume they were later replaced by movable magnets?
The resistance of the coil described is 230 ohms - what does your coil ohm-out at? Connections might suggest an electrostatic shunt (later replaced by the outer aquadag?) Cheers,
__________________
Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! |
#3
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Quote:
I suspect that the 3NP4 crt (which ran at 25kV) had an aluminized screen and did not require an ion trap. Still puzzled jr |
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