11-01-2021, 05:50 PM
Hi Buzz,
A few things I noticed. Behind the tuning knob there should be a cardboard pointer it's missing. This is what it looks like http://www.renovatedradios.com/product.php?product=255
When measuring the resistance of the filament winding all of the tubes and pilot lamps must be removed from that circuit. If not you are measuring the resistance of the tube's filament resistance along with the transformer's.
This is just a preference issue but you may find it easier to measure the opt by measuring the resistance between pins 2 and 3 of the 42. Those are the plate and screen grid. The fc can be measured from the screen grid of the 42 to the + side of the 1st filter cap or one of the filament pin on the 80 tube. This way you won't have to snip any wires and you could do it with out even flipping over the chassis.
To check the pri of the ant coil unplug the set from the wall. Turn the set on and volume full up. Measure the resistance from the ant post to the gnd post. Should see a low resistance. With the volume control in the off position you could measure a low resistance from the control and not the coil as they are in parallel.
To get rid of the squeal loosen the trimmer with the fiber nut abt a 1/4 turn. It's below 77 tube at the back corner. Be careful those fiber nuts are somewhat fragile.
The 80 and 84's are a little different animal from your standard 5 tube superhet.
A few things I noticed. Behind the tuning knob there should be a cardboard pointer it's missing. This is what it looks like http://www.renovatedradios.com/product.php?product=255
When measuring the resistance of the filament winding all of the tubes and pilot lamps must be removed from that circuit. If not you are measuring the resistance of the tube's filament resistance along with the transformer's.
This is just a preference issue but you may find it easier to measure the opt by measuring the resistance between pins 2 and 3 of the 42. Those are the plate and screen grid. The fc can be measured from the screen grid of the 42 to the + side of the 1st filter cap or one of the filament pin on the 80 tube. This way you won't have to snip any wires and you could do it with out even flipping over the chassis.
To check the pri of the ant coil unplug the set from the wall. Turn the set on and volume full up. Measure the resistance from the ant post to the gnd post. Should see a low resistance. With the volume control in the off position you could measure a low resistance from the control and not the coil as they are in parallel.
To get rid of the squeal loosen the trimmer with the fiber nut abt a 1/4 turn. It's below 77 tube at the back corner. Be careful those fiber nuts are somewhat fragile.
The 80 and 84's are a little different animal from your standard 5 tube superhet.
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
