Can this FM detector even work?

[Bobby Dip]

Originally Posted by earlyfilm

Bob, Congratulations on solving the sound issue!

By the way, since your first pictures in another thread did not show a power supply, what are you using for one now?

James.

Hi James, there is one large gauge wire going into the chassis that powers the tube filaments. It must be 12V, and originally came from the car battery. (The 6V tubes are wired as pairs in series.) I'm using a large switching power supply, and the TV is drawing 4.5A.

There is a single "B+" input on the TV chassis. (This must have come from a separate power supply that is missing.) There is a 300V electrolytic directly on the raw B+ line. The 6S4-A tube has only one recommended operating voltage on the data sheet, 250V. So 250V seemed like a good choice. (So far no smoke, fingers crossed.)

I just happened to have a pair of Heathkit HV power supplies model IP-17. These are rated at 100mA, 0 to 400V. It became apparent that 100mA was not enough to power the set, so I modified the pair to act a one 200mA supply. Each unit had 2 6L6s in paralled as series pass regulators. So there are now 4 6L6s in parallel.

So 12V @ 4.5A DC (could probably use AC) for the filaments. And 250V DC @200ma DC for B+. Once the set is totally restored, I plan on building a dedicated power supply for both "A" and "B+".

Bob D.