Thanks, Don.
JFD Type "C" is an universal replacement ballast. It can be programmed to replace many ballast types. Under the tube will be metal straps. They can be cut for different uses.
A ballast will operate very hot and might smoke until dust is burned off. Ballast tubes are used as a series resistor for dropping filament voltage. If tube filaments still light it should be good.
Knowing your radio model number might help identify the original ballast?
You can find information here for replacing a ballast using other components:
http://www.vintage-radio.com/repair-restore-information/valve_dropper-calcs.html
Norm
:Just wondering if anyone has any expertise on ballast tubes? Never did find any info on this chassis, but thanks to some help with all of you, finally got my mystery chassis working (kind of). Recapped the entire thing, put in a new eye tube, and got hold of an old 4 pin ballast tube. Brought up power slowly and it came to life. Played like a champ for about an hour! Then came the heartbreak, the ballast tube started smoking.. let it cool down and opened it up.. the thing was full of corrosion and rust, the filaments were shot. The problem is, this thing is so rusted i cant make out much of what was stamped on the housing except "JFD Adjustable AC-DC Ballast Type C".
:No part number, model number, etc.. Any ideas what I can replace this part with? Any help for this beginner would be appreciated!
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:Thanks, Don.