Back to that ).5 mFD capacitor: The concept was explained that the outer foil would tie to the ground, to shield from hum and noise pickup. Paper caps made with the right oil will last a long time if used within their ratings. BUT they could have problems. then plastic film capacitors were developed when reliable plastic film could be produced. And they were cheaper, so they took over. Now we have silver-mica capacitors which are still better but cost quite a bit more.

Yes, that's how I remember it too. I remember ripping those things apart and being amazed at the length of the foils.

 

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

ak

I have that exact radio in storage ... a it for 40 plus years ... dragged it across the country with me. It really needs someone to go through it ... check it over ... set it up correctly.

Not sure who I can find to do this (when I pull it out of storage).

 

I have that exact radio in storage ... a it for 40 plus years ... dragged it across the country with me. It really needs someone to go through it ... check it over ... set it up correctly.

Not sure who I can find to do this (when I pull it out of storage).

It's not an easy procedure having done it a few times from beginning to end. It will be expensive so it's better to sell the radio IMO.
https://www.navy-radio.com/manuals/r390a-maint-ct-school.pdf

NAVAL TECHNICAL TRAINING CENTER
PENSACOLA, FLORIDA
CRYPTOLOGIC TECHNICIAN CLASS "A"
CRYPTOLOGIC MAINTENANCE COURSE

There is even a SSB conversion procedure.

 

Hello,

The internet archive has a collection of the old "radio craft" magazine:
https://archive.org/details/Radio-Craft

On the website : http://www.tubebooks.org/ , you can find a lot of vintage information.
For tube data as PDF's, you can have a look here:
http://www.nj7p.info/Tubes/PDFs/Tube.html
Or this site:
https://frank.pocnet.net/
The manufacturers list from the same site:
https://frank.pocnet.net/other/mfgindex.html
Here is site with a lot more tube based schematics:
http://www.nucow.com/120,000FREE.htm
Here I found a collection of Tube databooks on the internet archive:
https://archive.org/details/Tubes_Datasheets
Here I found a page with a lot of old manuals (including a lot of heathkit):
https://www.vintage-radio.info/
There are also a lot of old books on the Internet Archive:
https://archive.org/details/VacuumTubesBooks?and[]=languageSorter:"English"
DXzone has also a page with some links:
https://www.dxzone.com/catalog/Antique_Radios/Schematics/

Bertus