01-16-2019, 11:32 AM
I now have the chassis out of the coffin. First thing I noticed was a small amount of millet bird seed and mouse droppings but no chew marks on insulation. Measurements show all the coils are good with the exception of PT primary, bad toggle switch to deal with later. Probably the reason the radio was retired. Something I noticed was the phone plug for the headphones was mounted to the front panel without an insulating washer. The schematic shows that the jack is un-grounded, if I'm not mistaken. The jack looks fairly new.
http://www.nostalgiaair.org/pagesbymodel...013735.pdf
The carbon resistors are suspended between clips and are way out of tolerance. They are 3 meg and 155K, s/b 2 meg and 70K. Any ideas how to substitute for these? If they were the glass type I would just remove the ends and insert the correct resistor. The 70K is in the power supply and I'm thinking either 68K or 72K at two watts.
I also noticed one of the hum controls on the PT secondary doesn't have a connection on the wiper. Since the controls are exposed wirewound I pressed on the wiper and it registered on the ohmmeter. Quick fix for that.
I'm digging out the vacuum cleaner next and attempting to make the toggle switch work. If it doesn't then cut the wires. Getting a list of needed caps and tubes together.
I will probably wire in a fuse on the PT primary. Any thoughts to adding safety caps since the chassis is not earth ground?
All for now. Rod
http://www.nostalgiaair.org/pagesbymodel...013735.pdf
The carbon resistors are suspended between clips and are way out of tolerance. They are 3 meg and 155K, s/b 2 meg and 70K. Any ideas how to substitute for these? If they were the glass type I would just remove the ends and insert the correct resistor. The 70K is in the power supply and I'm thinking either 68K or 72K at two watts.
I also noticed one of the hum controls on the PT secondary doesn't have a connection on the wiper. Since the controls are exposed wirewound I pressed on the wiper and it registered on the ohmmeter. Quick fix for that.
I'm digging out the vacuum cleaner next and attempting to make the toggle switch work. If it doesn't then cut the wires. Getting a list of needed caps and tubes together.
I will probably wire in a fuse on the PT primary. Any thoughts to adding safety caps since the chassis is not earth ground?
All for now. Rod