Two Northern Electric Baby Champ Tube Radios Video #4 - Another AVC Capacitor Investigation

I investigate the AVC capacitor and its effects in the two band Baby Champ radio.

[@michaelmacdonald3408]

Dial tracking might be out replace all wax caps and leave alone mica ones the big square caps it takes special test equipment to test them properly.

[@deanmakin5762]

The mica mold capacitor when tested did not open fully indicating it is leaky

[@silverXnoise]

Only up at 450V, I don’t think it has ever seen 450V until that test.

[@hestheMaster]

The busy but accurate schematic shows B- separate from chassis because it is the neutral side of the AC supply! The three 12 Volt tubes must be metal can RCA type tubes for things to work right as the can is clearly marked to the chassis ground all go to pin 1! B- and chassis ground are separated by (C-31) a 0.2uF cap. You MUST use a polarized line cord to safely use the radio today no biggie if it will be sold to some unsuspecting purchaser one day. So you found the nub of a previously cut connection on the B-? Call it "too many cooks (kooks) spoil the soup". Maybe take notes on what you did to each radio when you work on them IF you don't film everything. PS if you use a polarized line cord the 12SQ7 tube can be a 12SQ7-GT (glass) as it only acts like a diode in the circuit.

[@michaelmacdonald3408]

I would put it back in.

[@michaelmacdonald3408]

RF capacitors are hand picked if you replace it your dial maybe out.