12-28-2013, 04:36 PM
As things developed today, I received my order of a new electrolytic and other capacitors to finish the restoration of the electronic circuitry. The electrolytic I used the first time around was intermittently shorting. I could actually hear it popping inside during the warm-up of the tubes. You could also feel the pops coming through the can shield. Instead of a capacitor with the same voltage rating, this time I went for a 450VDC rated 20mFd capacitor. It should last for a long time. The other polypropylene capacitors from tubesandmore allowed me to finish replacing all the capacitors except for the mica capacitors and they are working fine with no signs of leakage or problems of any kind.
I notice that the 16 ohm resistor in the filament circuit going to the power pilot lamp drops the current low enough when an 1847 dial lamp is used that a person can easily hold the lamp in their fingers without getting uncomfortable holding it. This should help extend the life of the lamp and also the life of the plastic jewel that covers it on the front of the cabinet.
I will start on the electrostatic shield rebuild soon. I had already determined that the old paper arrangement is too far gone to repair, so that part will get soaked in water until the paper is ready to fall apart. It probably won't take too long as brittle and crumbling as it is now. I have some nice brown Kraft paper to use in re-creating the assembly. I plan to make a construction jig out of some thin plywood to hold the copper wires straight with the first layer of paper underneath them and the copper tape strip to one side. Once I get things lined up, I can solder the wires to the copper tape, then spray over the wires and paper with spray adhesive. Then another piece of Kraft paper will be laid on top of that and smoothed out until the wires are held securely enough. Adequate drying time should be good to keep the wires in place while the whole is wrapped around the wooden oval supports for each end and then stapled. I will take some pictures as I go and post them on the Phorum.
Sure is nice to have the radio working and see the glow of the tubes! Thanks everyone for your help.
Joe
I notice that the 16 ohm resistor in the filament circuit going to the power pilot lamp drops the current low enough when an 1847 dial lamp is used that a person can easily hold the lamp in their fingers without getting uncomfortable holding it. This should help extend the life of the lamp and also the life of the plastic jewel that covers it on the front of the cabinet.
I will start on the electrostatic shield rebuild soon. I had already determined that the old paper arrangement is too far gone to repair, so that part will get soaked in water until the paper is ready to fall apart. It probably won't take too long as brittle and crumbling as it is now. I have some nice brown Kraft paper to use in re-creating the assembly. I plan to make a construction jig out of some thin plywood to hold the copper wires straight with the first layer of paper underneath them and the copper tape strip to one side. Once I get things lined up, I can solder the wires to the copper tape, then spray over the wires and paper with spray adhesive. Then another piece of Kraft paper will be laid on top of that and smoothed out until the wires are held securely enough. Adequate drying time should be good to keep the wires in place while the whole is wrapped around the wooden oval supports for each end and then stapled. I will take some pictures as I go and post them on the Phorum.
Sure is nice to have the radio working and see the glow of the tubes! Thanks everyone for your help.
Joe
