11-07-2011, 11:23 PM
And you need them for what reason? If it is to check the coil windings that can be done easily with an ohm meter. There are two that are typically a problem. One is the ant coil primary and two the cathode winding on the oscillator coil. Only have had one set with bad IF transformer and was able to repair. (broken wire at the winding)
Generally they rot and go open. Symptoms are for the ant coil is poor sensitivity. With the osc coil set will only pick up a station or two in the wrong place on the dial and osc won't run.
To check just use an ohm meter to measure the resistance of the winding. All if good should show a low resistance like less than 10 ohms. The exception for that is the winding in the IF transformer. Some may read higher like 50 ohms. If any are bad you'll get a reading of a few thousands ohms or higher.
I didn't look at the diagram but I'm pretty sure you can measure them in circuit but the ant primary you must have the volume full up or you will be measuring the resistance of the volume control.
Rewinding is pretty easy nothing too scary.
Terry
ps I don't have a rms reading meter either but don't tell anyone!
Generally they rot and go open. Symptoms are for the ant coil is poor sensitivity. With the osc coil set will only pick up a station or two in the wrong place on the dial and osc won't run.
To check just use an ohm meter to measure the resistance of the winding. All if good should show a low resistance like less than 10 ohms. The exception for that is the winding in the IF transformer. Some may read higher like 50 ohms. If any are bad you'll get a reading of a few thousands ohms or higher.
I didn't look at the diagram but I'm pretty sure you can measure them in circuit but the ant primary you must have the volume full up or you will be measuring the resistance of the volume control.
Rewinding is pretty easy nothing too scary.
Terry
ps I don't have a rms reading meter either but don't tell anyone!
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
